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  • Triticum aestivum  (853)
  • Springer  (853)
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  • 1
    ISSN: 1573-8264
    Keywords: carboxylation efficiecy ; carotenoids ; chlorophyll ; growth analysis ; net photosynthetic rate ; photochemical efficiency ; ribulose 1,5-bisphosphate carboxylase/oxygenase ; stomatal conductance ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat plants were grown from sowing to day 18 in 26-dm3 chambers at three different CO2 concentrations: 150 (-CO2), 350 (C, control), 800 (+CO2) μmol mol-1. Afterwards, plants of the three variants were grown at the same natural CO2 concentration. Plant characteristics were measured just before the transfer (0 days after CO2 treatment, DAT), and at 5 – 8 DAT on the 1st leaf, and at 12 – 22 DAT on the 4th leaf. Decreased or increased CO2 concentrations caused acclimations which persisted after transplantation to natural CO2 concentration. At 5 – 8 DAT, stomatal density, stomatal conductance (gs), CO2 saturated net photosynthetic rate (PNsat0), radiation saturated net photosynthetic rate (PNsat1), and carboxylation efficiency (τ) were higher in -CO2 plants and lower in +CO2 plants than in C plants. As compared with C plants, the photochemical efficiency (α) was lower in -CO2 and higher in -CO2 plants, however, chlorophyll (Chl) a, Chl b, Chl a–b and carotenoid contents were lower in both -CO2 and +CO2 plants. On the 4th leaf, which emerged on plant after finishing CO2 treatments, at 12 – 22 DAT, no differences in stomatal density and g, between treatments were observed. In -CO2 plants, pigment content and PNsat0 were higher, α was lower, and PNsat1 and τ were not different from C plants. In contrast, in +CO2 plants, pigment content, PNsat1 and τ were lower, and PNsat0 and α were unchanged. Leaf area, dry mass, and tiller development increased in +CO2 plants and decreased in -CO2 plants. In the interval between 8 and 22 DAT, lower net assimilation rate in +CO2 than in -CO2 plants was observed.
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  • 2
    ISSN: 1573-8264
    Keywords: ascorbic acid ; ascorbate peroxidase ; active oxygen species ; catalase ; hydroger ; peroxide ; oxidative stress ; superoxide dismutase ; temperature stress ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An experiment was conducted with three wheat (Triticum aestivum L.) genotypes C 306, HD 2285 and HD 2329 (differently susceptible to water and temperature stress) to study the extent of oxidative injury and activities of antioxidant enzymes in relation to heat stress induced by manipulating dates of sowing. Increase in temperature by late sowing significantly decreased leaf relative water content (RWC), ascorbic acid content, and increased H2O2 content and lipid peroxidation in all the genotypes at 8 and 23 d after anthesis. Temperature tolerant genotypes C 306, closely followed by HD 2285 were superior to HD 2329 in maintaining high RWC, ascorbic acid content, and lower H2O2 content and lipid peroxidation (malondialdehyde content) under high temperature (late sowing) at the two stages. Activities of superoxide dismutase and catalase were highest in HD 2285 followed by C 306 and minimum in HD 2329 while ascorbate peroxidase activity was highest in C 306.
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  • 3
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    Biologia plantarum 43 (2000), S. 309-311 
    ISSN: 1573-8264
    Keywords: grains ; maturation ; radioisotopes ; transport ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Steam-girdling experiments with detached wheat shoots showed that cesium was eliminated from the xylem sap and loaded into the phloem during acropetal transport. This transfer is important for the accumulation of cesium (especially also of the radiopollutants 134Cs and 137Cs) in maturing wheat grains.
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  • 4
    ISSN: 1573-8264
    Keywords: active oxygen species ; catalase ; chloroplast ; glutathione reductase ; lipid peroxidation ; nitrate reductase ; proline ; superoxide dismutase ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We induced an oxidative stress by means of exogenous hydrogen peroxide in two wheat genotypes, C 306 (tolerant to water stress) and Hira (susceptible to water stress), and investigated oxidative injury and changes in antioxidant enzymes activity. H2O2 treatment caused chlorophyll degradation, lipid peroxidation, decreased membrane stability and activity of nitrate reductase. Hydrogen peroxide increased the activity of antioxidant enzymes, glutathione reductase and catalase. These effects increased with increasing H2O2 concentrations. However, no change was observed in the activity of superoxide dismutase and proline accumulation.
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  • 5
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    Biologia plantarum 43 (2000), S. 559-562 
    ISSN: 1573-8264
    Keywords: phenolics ; susceptibility ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyphenol oxidase activity was higher in resistant wheat cultivar ACC-8226 than in susceptible cultivar MP-845 in control sets and after inoculation of Alternaria triticina. However, similar polyphenol oxidase isozyme pattern was found in control and inoculated sets of both the cultivars, but the band intensity was higher after inoculation. Three and four peroxidase isozymes were found in ACC-8226 and MP-845, respectively. An extra peroxidase isozyme band was observed in both the cultivars after inoculation. The results suggest an active role of peroxidase and polyphenol oxidase in defence mechanism of wheat plants.
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  • 6
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    Biologia plantarum 43 (2000), S. 61-66 
    ISSN: 1573-8264
    Keywords: lipids ; polypeptide pattern ; salt stress ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat seedlings of a salt tolerant cultivar were grown hydroponically in presence and absence of 100 mM NaCl. Roots were harvested, and the plasma membrane (PM) fraction was purified. PM ATPase required a divalent cations for activity (Mg 〉 Mn 〉 Ca 〉 Co 〉 Zn 〉 Ni 〉 Cu), and it was further stimulated by monovalent cations (K 〉 Rb 〉 NH4 〉 Li 〉 choline 〉 Cs). The pH optima were 6.0 and 5.6 in absence and presence of 25 mM KCl, respectively. The enzyme was sensitive to vanadate and DCCD but insensitive to azide, oligomycine and nitrate. The enzyme displayed a high preference for ATP but was also able to hydrolyze other nucleotide tri- and diphosphates. The enzyme activity showed a simple Michaelis-Menten kinetics for the substrate Mg2+-ATP in both control and salt exposed roots. The polypeptide patterns of control and salt stressed PM fractions, detected by SDS-PAGE, were very similar. NaCl substantially reduced the PM ATPase specific activity, whereas it had little effect on the apparent Km for Mg2+-ATP. Since the root PM ATPase of salt sensitive and resistant genotypes responded similarly to salinity stress, it seems unlikely that the mechanism of salt tolerance in wheat is primarily based on differences in PM ATPase characteristics.
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  • 7
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    Biologia plantarum 43 (2000), S. 257-262 
    ISSN: 1573-8264
    Keywords: nitrate assimilation ; Triticum aestivum ; Zn toxicity ; Cu toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of Zn2- on nitrate reductase (NR, EC 1.6.6.1) activity was studied in botá wheat (Triticum aestivum cv. Oasis) leaves and in the NR enzyme partially purified from wheat leaves. Leaf segments were floated on 0 to 5 mM ZnSO4 solutions (pH 6.0) for 24 h under continuous light. Zn2- at 250 μM decreased NR activity and increased membrane permeability. However, parameters of cellular oxidative damage were scarcely affected by Zn2- treatments. Accordingly, the decrease of NR activity induced by Zn2- was not prevented by benzoate (a scavenger of oxygen radicals). The effect of Zn2- was dependent on leaf age: it decreased NR activity in mature but not in young leaves. Zn2 inhibited the partially purified NR. This inhibition was not reversed by either co- or post-incubation with cysteine, and the amount of -SH groups of the purified NR was not affected by Zn2+ indicating that Zn2- inhibition does not involve key -SH groups of the enzyme. However, o-phenantroline both prevented and reversed Zn2+-induced NR inhibition. We concluded that the effect of Zn2+ on NR activity in vivo is not associated with an increase in active oxygen generation and involves a direct and reversible inhibition of the enzyme.
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  • 8
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    Biologia plantarum 43 (2000), S. 523-528 
    ISSN: 1573-8264
    Keywords: accumulation ; grains ; lithium ; mobility ; phloem ; potassium ; rubidium ; sodium ; strontium ; Triticum aestivum ; xylem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The alkali metals cesium, rubidium, lithium and sodium were introduced together with strontium via flaps into leaf laminas or into the stem of maturing, intact winter wheat (Triticum aestivum L. cv. Arina) grown in a field. Long-distance transport of these elements and the influence of the application date and of different application positions were investigated. The phloem-immobile Sr served as a marker for the distribution of the xylem sap in the plants. Dry matter accumulation in the grains and the transpiration per shoot were not markedly affected by the treatments as compared to control plants. The phloem mobility was rather high for Cs and Rb. Li was almost immobile in the phloem (similarly to Sr). An application into the cut stem xylem below the second leaf node contributed more to the contents in the grains than an application into the flag leaf. An earlier feeding date led to a higher accumulation in the grains. The marked losses of the elements applied during maturation (most pronounced for Li) can be explained by leakage in the rain.
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  • 9
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    Sciences of soils 5 (2000), S. 10-21 
    ISSN: 1432-9492
    Keywords: Soil temperature ; Triticum aestivum ; Stubble retention ; Nitrogen ; Early growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Early growth and development are often lower when wheat is sown into standing stubble. A study was conducted to determine whether this difference in early growth could be explained by the effects of stubble on soil temperature in the vicinity of the young plant. The roles of nitrogen nutrition and soil strength were also assessed. Three crops were monitored (1990–1992), with the wheat being sown into either standing wheat stubble after a no-till fallow (NT), or into no-tilled plots from which the stubble had been removed by burning (NB). Measurements were made of wheat growth and development, soil and plant N, soil temperature and penetration resistance. The site was on a black earth near Warialda in the northern wheatbelt of New South Wales, Australia. In 1992 wheat was also grown under simulated stubble to isolate the shading and soil temperature effects of stubble from other factors. A significant (P〈0.05) relationship was found between average soil temperature and above ground dry matter (DM) at 65 days after sowing (DAS) but not at 107 DAS. This relationship accounted for differences in DM production at 65 DAS between NT and NB treatments in 1991 and 1992, but not in 1990. In that year the lower DM production in NT plots was associated with poorer N nutrition, and possibly disease. Laboratory incubations indicate that immobilisation of N as stubble decomposed could have contributed to this. Burning stubble produced no immediate increase in soil N availability, so that it is unlikely that N contained in stubble contributed to the difference. Soil strength differences between treatments and phytotoxic effects are unlikely to have contributed to growth differences in this soil.
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  • 10
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    Russian journal of plant physiology 47 (2000), S. 734-739 
    ISSN: 1608-3407
    Keywords: Triticum aestivum ; bioelectric potentials ; frost resistance ; critical points
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Winter wheat (Triticum aestivum L.) seedlings of three cultivars differing in frost resistance were used to study cooling-induced changes in the bioelectric potential. Measurements were performed with nonfreezing graphite–glycerol electrodes in the regime of monitoring. Upon a gradual change in air temperature from 20 to –15°C at the rates of 20 and 2°C/h, the bioelectric potential underwent abrupt transitions at certain moments, indicating changes in the physiological condition of plants. The time required for the achievement of these critical states, as well as the survival of plants after thawing, depended both on the temperature and the cooling rate. Apparently, these characteristics were related to the dynamics of phase transitions of water. Cultivar-specific features were manifested in the different abilities of plants to maintain free water in a supercooled state. It is supposed that the critical points are related to the cold resistance of colloid systems and to the temperature lethal for plants.
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  • 11
    ISSN: 1432-2242
    Keywords: Key words Wheat ; High-molecular-weight glutenin ; AS-PCR ; Glu-A1 locus ; Null allele ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The present work reports new PCR markers that amplify the complete coding sequence of the specific alleles of the high molecular weight (HMW) glutenin genes. A set of AS-PCR molecular markers was designed which use primers from nucleotide sequences of the Glu-A1 and Glu-D1 genes, making use of the minor diffeences between the sequences of the x1, x2* of Glu-A1, and the x5 and y10 of Glu-D1. These primers were able to distinguish between x2* and the x1 or xNull of Glu-A1. Also x5 was distinguishable from x2, and y10 from y12. The primers amplified the complete coding regions and corresponded to the upstream and downstream flanking positions of Glu-A1 and Glu-D1. Primers designed to amplify the Glu-A1 gene amplified a single product when used with genomic DNA of common wheats and the xNull allele of this gene. This work also describes the cloning and characterisation of the nucleotide sequence of this allele. It possesses the same general structure as x2* and x1 (previously determined) and differs from these alleles in the extension of the coding sequence for a presumptive mature protein with only 384 residues. This is due to the presence of a stop codon (TAA) 1215-bp downstream from the start codon. A further stop codon (TAG), 2280-bp downstream from the starting codon is also found. The open reading frame of xNull and x1 alleles has the same size in bp. Both are larger than x2* which shows two small deletions. The reduced size of the presumptive mature protein encoded by xNull could explain the negative effect of this allele on grain quality.
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  • 12
    ISSN: 1432-2242
    Keywords: Keywords Composite populations ; Triticum aestivum ; Blumeria (Erysiphe) graminis f. sp. tritici ; Residual resistance effects ; Quantitative resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The evolution of adult plant resistance towards powdery mildew (caused by Blumeria graminis f. sp. tritici) was investigated in 11 wheat populations cultivated for 10 years in a French network for dynamic management (DM) of wheat genetic resources. The aims of the study were to compare the evolution of resistance in sites submitted to different powdery mildew pressure and to investigate the implication of specific resistance gene action in adult plant resistance. For this, 7 of the 11 populations were characterized for their composition of specific resistance genes (results presented in a former paper). Even though no population differed significantly from the initial PA0 pool for mean adult plant resistance, divergence appeared among the final populations. The populations with the highest adult plant resistance level originated from sites where powdery mildew pressure is known to be high (Vervins, Le Rheu), whereas populations with the lowest adult plant resistance corresponded to areas with no, or very low, powdery mildew pressure (Toulouse, Montreuil-Bellay). A residual effect of defeated specific resistance genes was hypothesized, as lines accumulating at least two specific resistance genes appeared more resistant. Additional quantitative resistance seemed to be involved in adult plant resistance. DM lines appeared then as an interesting source of variability for resistance towards powdery mildew. Moreover, as these lines had been grown in mixed populations they may be appropriate as components of a composite cultivar.
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  • 13
    ISSN: 1432-2242
    Keywords: Key words Glutenin ; Triticum aestivum ; Wheat storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Low-molecular-weight (LMW) glutenin subunits consist mainly of two domains, one at the N- terminus which contains repeats of short amino-acid motifs, and a non-repetitive one rich in cysteine, at the C- terminal region. In previous reports, polyacrylamide-gel electrophoresis has been used to show that large size variation exists among LMW and HMW glutenin subunits, and it has been suggested that deletions and insertions within the repetitive region are responsible for these variations in length. In this study, PCR-amplification of genomic DNA (Triticum aestivum variety Chinese Spring) was used to isolate three full-length LMW glutenin genes: LMWG-MB1, LMWG-MB2 and LMWG-MB3. The deduced amino-acid sequences show a high similarity between these ORFs, and with those of other LMW glutenin genes. Comparisons indicate that LMWG-MB1 has probably lost a 12-bp fragment through deletion and that LMWG-MB1 and LMWG-MB2 have an insertion of 81 bp within the repetitive domain. The current study has shown direct evidence that insertions and/or deletions provide a mechanistic explanation for the allelic variation, and the resultant evolution, of prolamin genes. Single-base substitutions at identical sites generate stop codons in both LMWG-MB2 and LMWG-MB3 indicating that these clones are pseudogenes.
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  • 14
    ISSN: 1432-2242
    Keywords: Keywords AFLPs ; Bulked segregant analysis ; Marker-assisted selection ; Microsatellites ; Powdery mildew resistance ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Molecular markers were identified in common wheat for the Pm24 locus conferring resistance to different isolates of the powdery mildew pathogen, Erysiphe graminis DM f. sp. tritici (Em. Marchal). Bulked segregant analysis was used to identify amplified fragment length polymorphism (AFLP) markers and microsatellite markers linked to the gene Pm24 in an F2 progeny from the cross Chinese Spring (susceptible)× Chiyacao (resistant). Two AFLP markers XACA/CTA-407 and XACA/CCG-420, and three microsatellite markers Xgwm106, Xgwm337 and Xgwm458, were mapped in coupling phase to the Pm24 locus. The AFLP marker locus XACA/CTA-407 co-segregated with the Pm24 gene, and XACA/CCG-420 mapped 4.5 cM from this gene. Another AFLP marker locus XAAT/CCA-346 co- segregated in repulsion phase with the Pm24 locus. Pm24 was mapped close to the centromere on the short arm of chromosome 1D, contrary to the previously reported location on chromosome 6D. Pm24 segregated independently of gene Pm22, also located on chromosome 1D. An allele of microsatellite locus Xgwm337 located 2.4±1.2 cM from Pm24 was shown to be diagnostic and therefore potentially useful for pyramiding two or more genes for powdery mildew resistance in a single genotype.
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  • 15
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    Theoretical and applied genetics 100 (2000), S. 519-527 
    ISSN: 1432-2242
    Keywords: Key words Wheat ; Triticum aestivum ; Physical mapping ; Deletion lines ; RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Extended physical maps of chromosomes 6A, 6B and 6D of common wheat (Triticum aestivum L. em Thell., 2n=6x=42, AABBDD) were constructed with 107 DNA clones and 45 homoeologous group-6 deletion lines. Two-hundred and ten RFLP loci were mapped, including three orthologous loci with each of 34 clones, two orthologous loci with each of 31 clones, one locus with 40 clones, two paralogous loci with one clone, and four loci, including three orthologs and one paralog, with one clone. Fifty five, 74 and 81 loci were mapped in 6A, 6B and 6D, respectively. The linear orders of the mapped orthologous loci in 6A, 6B and 6D appear to be identical and 65 loci were placed on a group-6 consensus physical map. Comparison of the consensus physical map with eight linkage maps of homoeologous group-6 chromosomes from six Triticeaespecies disclosed that the linear orders of the loci on the maps are largely, if not entirely, conserved. The relative distributions of loci on the physical and linkage maps differ markedly, however. On most of the linkage maps, the loci are either distributed relatively evenly or clustered around the centromere. In contrast, approximately 90% of the loci on the three physical maps are located either in the distal one-half or the distal two-thirds of the six chromosome arms and most of the loci are clustered in two or three segments in each chromosome.
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  • 16
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    Theoretical and applied genetics 100 (2000), S. 32-38 
    ISSN: 1432-2242
    Keywords: Key words Waxy (Wx) protein ; Triticum aestivum ; Amylose content ; Starch ; Rapid Visco-Analyzer ; Swelling power ; Noodle quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Waxy (Wx) protein is a granule-bound starch synthase (GBSS) responsible for amylose production in cereal endosperm. Eight isolines of wheat (Triticum aestivum L.) having different combinations of presence and absence of three Wx proteins, Wx-A1, -B1, and -D1, were produced in order to elucidate the effect of Wx protein deficiencies on the apparent amylose content and starch-pasting properties. An improved SDS gel electrophoresis showed that ’Bai Huo’ (a parental wheat) carried a variant Wx-B1 protein from an allele, Wx-B1e. Thus, wheat lines of types 1, 2, 4, and 6 examined in this study contained a variant Wx-B1 allele and not the standard allele, Wx-B1a. The results from 3 years of experiments using 176 lines derived from two cross-combinations showed that apparent amylose content increased the least in type 8 (waxy) having no Wx proteins and, in ascending order, increased in type 5 (only the Wx-A1 protein is present) 〈type 7 (Wx-D1) 〈type 6 (Wx-B1) 〈type 3 (Wx-A1 and -D1) 〈type 4 (Wx-A1 and -B1) 〈type 2 (Wx-B1 and -D1) 〈type 1 (three Wx proteins). However, Tukey’ s studentized range test did not detect significant differences in some cases. Densitometric analysis suggested that the amylose content was related to the amount of the Wx protein in the eight types. Parameters in the Rapid Visco-Analyzer test and swelling power were correlated to amylose content. Consequently, amylose content and pasting properties of starch were determined to be influenced the most by the lack of the Wx-B1 protein, followed by a lack of Wx-D1, and leastly by the Wx-A1 deficiency, which indicated the presence of differential effects of the three null alleles for the Wx protein.
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  • 17
    ISSN: 1432-2242
    Keywords: Key words Composite populations ; Triticum aestivum ; Blumeria (Erysiphe) graminis f. sp. tritici ; Selection ; Drift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Dynamic management has been proposed as a complementary strategy to gene banks for the conservation of genetic resources. The evolution of frequencies of genes for specific resistance towards powdery mildew (caused by Blumeria graminis f. sp. tritici) in populations of a French network for dynamic management of bread wheat genetic resources was investigated after 10 years of multiplication without human selection. The objective was to determine whether specific resistance gene diversity was maintained in the populations and whether any changes could be attributed to selection due to pathogen pressure. Seven populations, originating from four of the network sites, were characterized and compared to the initial population for six specific resistance gene frequencies detected by nine Blumeria graminis f. sp. tritici isolates. Diversity decreased at the population level, but because of a strong differentiation between the populations, this diversity was maintained at the network level. The comparison of Fst parameters estimated on neutral markers (RFLP) and on resistance gene data revealed that in two of the populations specific resistance genes had been selected by pathogen pressure, whereas evolution in two other populations seemed to be the result of genetic drift. For the three last populations, conclusions were less clear, as one had probably experienced a strong bottleneck and the other two presented intermediate Fst values. A dynamic management network with sites contrasted for pathogen pressure, allowing genetic drift in some populations and selection in others, appeared, at least on the short term, to be a good tool for maintaining the diversity of genes for specific resistance to powdery mildew.
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  • 18
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    Nutrient cycling in agroecosystems 56 (2000), S. 59-68 
    ISSN: 1573-0867
    Keywords: bicarbonate-extractable potassium ; muriate of potash ; potassium ; potassium chloride ; relative effectiveness ; silicate rock powder ; Triticum aestivum ; Trifolium subterraneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Granite (silicate) rock dust, a by-product of quarry operations, is being advocated and used as a fertilizer in the wheatbelt of south-western Australia (WA). The dust is insoluble and based on its nutrient element content (1.9% K and 0.3%P and negligible N) it is not expected to be a useful fertilizer. Previous laboratory studies and glasshouse experiments in WA suggest the dust is a slow release K fertilizer. This paper extends the previous studies to consider the dust as an NP or K fertilizer in the year of application in a field experiment on a soil deficient in N, P and K. In addition, the effectiveness of the dust as a K fertilizer was compared with the effectiveness of KCl (muriate of potash), the K fertilizer used in WA at present, in glasshouse experiments using K deficient soils. In the field experiment, compared with NP fertilizer or NPK fertilizer (urea, supplying N; superphosphate, providing P, S, Ca, Cu, Zn and Mo; KCl providing K), the dust had no effect on grain yield of wheat (Triticum aestivum); in fact dust applied at 20 t ha-1, for unknown reasons, reduced yields by about 65% compared to the nil (no fertilizer, no dust) treatment. Relative to the nil treatment, applying NPK fertilizer increased yields about threefold, from 0.54 to 1.79 t ha. The glasshouse experiments showed that, relative to KCl, the dust was from about 0.02 to 14% as effective in K deficient grey sandy soils for producing dried tops of 30-day old wheat plants or 42-day old clover (Trifolium subterraneum) plants. In soils with adequate K (yellow sands, sandy loams or clays, loamy clays, clay loams and clays), neither KCl nor the dust affected yields of 30 to 42-day old wheat or clover plants grown in the glasshouse. In the glasshouse experiments, no yield depressions were measured for the dust applied up to 17 g dust per kg soil (equivalent to 17 t dust ha-1 mixed into the top 10 cm of soil in the field). It is concluded that the dust has no value as a fertilizer.
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  • 19
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    Nutrient cycling in agroecosystems 56 (2000), S. 117-123 
    ISSN: 1573-0867
    Keywords: labelled nitrogen ; Lolium perenne ; nitrogen cycling ; root biomass ; straw ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Large amounts of nitrogen (N) fertiliser (150–200 kg N/ha) are currently being applied to perennial ryegrass (Lolium perenneL.) seed crops in New Zealand. Due to increasing requirements for efficient use of N fertilisers and minimising nitrate contamination of the environment, a field experiment was established using 15N-labelled fertiliser to follow the fate of applied N. Urea-15N was applied to a perennial ryegrass seed crop in April (30 kg N/ha), August (30 kg N/ha), September (60 kg N/ha) and October (60 kg N/ha). The urea-15N was applied in solution and watered in to minimise volatilisation loss. At the time of harvest (December), 9% of the applied 15N was in the seed, 29% in the straw, 19% in the roots and 39% in the soil organic matter. Losses of 15N were minimal as the N was applied in several applications, each one at a relatively low rate, and at times when leaching was unlikely to occur. Ryegrass plants used a greater proportion of the N applied in September and October (61–65%) compared with that applied in April (44%). Consequently more N was recovered from the soil in the autumn application (57%) than from the September and October applications (28–44%). The availability of the residual fertiliser N to a subsequent wheat (Triticum aestivum L.) crop was studied in a glasshouse experiment. The residual fertiliser N was present in the soil and ryegrass roots and stubble. The wheat plants only recovered 7–9% of this residual N. Most of the N taken up by the wheat came from the soil organic N pool. Overall, applying a total of 180 kg N/ha to the ryegrass appeared to have minimal direct impact on the environment. In the short term N not used by the ryegrass plants contributed to the soil organic N pool.
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  • 20
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    Nutrient cycling in agroecosystems 56 (2000), S. 109-116 
    ISSN: 1573-0867
    Keywords: labelled nitrogen ; Lolium perenne ; nitrogen cycling ; root biomass ; straw ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field trial was carried out to compare the transformations and plant uptake of urine N and S in a short-term pasture from within an arable/pasture ley rotation and a long-term pasture. Animal urine labelled with 15N and 35S was applied to microplots at both sites. These microplots were destructively sampled at various time intervals over 12 months and analysed for 15N and 35S. It is known that soil organic matter accumulates under short-term pastures compared with a long-term pasture in which accumulation and degradation are in balance. Consequently, it was hypothesised that immobilization of urine N and S is more intense in the short-term. However, in this study there was considerably less immobilization of 15N and 35S into soil organic forms under short-term pasture than long-term pasture. This was attributable to a greater pasture dry matter response to urine application under the short-term pasture (due to its inherently low N fertility) resulting in a greater plant uptake of 15N and 35S with less 15N and 35S consequently being available for immobilization. At both sites, all of the applied 35S was accounted for through plant uptake and recovery in the soil, but 21–48% of the 15N was unaccounted for and presumed to have been lost through gaseous emissions. It was concluded that accumulation of soil organic N and S under short-term pastures is likely to be attributable to turnover of plant residues (particularly root material) and does not appear to be related to immobilization in urine patches.
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  • 21
    ISSN: 1573-5087
    Keywords: abscisic acid ; drought stress ; Triticum aestivum ; wheat germ agglutinin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Expression of wheat germ agglutinin (WGA) gene inthe developing embryos of wheat (Triticumaestivum L. cv. C-306) was studied in relation toabscisic acid (ABA) accumulation under water stressconditions. Imposition of water stress resulted inelevated ABA levels in the embryos at threedevelopmental stages (18, 24 and 30 DPA). On thecontrary, the effect of drought stress on WGAaccumulation was stage dependent with significantincrease in WGA content being observed at only 24 DPA. Our results suggest that apart from ABA, otherfactors which are temporally expressed, are alsoinvolved in regulation of WGA gene expression.
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  • 22
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    Chromosome research 8 (2000), S. 501-511 
    ISSN: 1573-6849
    Keywords: BFB cycle ; chromosome healing ; gametocidal factor ; rye deficiencies ; Secale cereale ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gametocidal factor on the Aegilops cylindrical chromosome 2Cc was used to induce and analyze the nature of chromosomal rearrangements in rye chromosomes added to wheat. For this purpose we isolated plants disomic for a given rye chromosome and monosomic for 2Cc and analyzed their progenies cytologically. Rearranged rye chromosomes were identified in 7% of the progenies and consisted of rye deficiencies (4.6%), wheat–rye dicentric and rye ring chromosomes (1.8%), and terminal translocations (0.6%). The dicentric and ring chromosomes initiated breakage–fusion–bridge cycles (BFB) that ceased within a few weeks after germination as the result of chromosome healing. Of 56 rye deficiencies identified, after backcrossing and selfing, only 33 were recovered in either homozygous or heterozygous condition covering all rye chromosomes except 7R. The low recovery rate is probably caused by the presence of multiple rearrangements induced in the wheat genome that resulted in poor plant vigor and seed set, low transmission, and an underestimation of the frequency of wheat–rye dicentric chromosomes. Genomic in-situ hybridization (GISH) analysis of the 33 recovered rye deficiencies revealed that 30 resulted from a single break in one chromosome arm followed by the loss of the segment distal to the breakpoint. Only three had a wheat segment attached distal to the breakpoint. Although some of the Gc-induced rye rearrangements were derived from BFB cycles, all of the recovered rye rearrangements were simple in structure. The healing of the broken chromosome ends was achieved either by the de-novo addition of telomeric repeats leading to deficiencies and telocentric chromosomes or by the fusion with other broken ends in the form of stable monocentric terminal translocation chromosomes.
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  • 23
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    Chromosome research 8 (2000), S. 671-676 
    ISSN: 1573-6849
    Keywords: meiotic metaphase I pairing ; recombinant isochromosome ; Triticum aestivum ; Triticum dicoccoides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A recombinant isochromosome i5BLrec of wheat was developed with one arm and the proximal 36% of the other arm of Chinese Spring (CS) origin and the distal 64% of the recombined arm of Triticum turgidum subsp. dicoccoides origin. The i5BLrec} provides an unusual opportunity to analyze the role of the centromere or arm heterozygosity in chromosome prealignment and synapsis during meiosis. In monosomic condition, the i5BLrec formed a ring univalent in 86.8% of the pollen mother cells (PMCs) at meiotic metaphase I. In the disomic condition, the two i5BLrec preferentially paired as a normal bivalent in 74.8% of the PMCs, which differed significantly (p〈0.01) from the normal bivalent pairing of 51% observed in diisosomic 5BL chromosomes of the CS (Di5BLCS) control plants. In plants with one i5BLrec and a normal 5BCS, the long arm of 5BCS paired with the homologous arm of i5BLrec in 54.4% of the PMCs, and 40.4% of the PMCs had a 5BCS univalent and a i5BLrec ring univalent. The implications of the i5BLrec pairing data on the mechanism of Ph1 gene action are discussed.
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  • 24
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    Plant and soil 222 (2000), S. 25-34 
    ISSN: 1573-5036
    Keywords: deficiency ; genotypic differences ; iron ; nutrient efficiency ; phytosiderophore ; tolerance ; Triticum aestivum ; Triticum durum ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tolerance to Zn deficiency in wheat germplasm may be inversely related to uptake and transport of Fe to shoots. The present study examined eight bread (Triticum aestivum) and two durum (T. turgidum L. conv. durum) wheat genotypes for their capacity to take up and transport Fe when grown under either Fe or Zn deficiency. Bread wheat genotypes Aroona, Excalibur and Stilleto showed tolerance to Zn and Fe deficiency, while durum wheat genotypes are clearly less tolerant to either deficiency. Roots of bread wheats tolerant to Zn deficiency exuded more phytosiderophores than sensitive bread and durum genotypes. Greater amounts of phytosideophores were exuded by roots grown under Fe than Zn deficiency. A relatively poor relationship existed between phytosiderophore exudation or the Fe uptake rate and relative shoot growth under Fe deficiency. At advanced stages of Zn deficiency, genotypes tolerant to Zn deficiency (Aroona and Stilleto) had a greater rate of Fe uptake than other genotypes. Zinc deficiency depressed the rate of Fe transport to shoots in all genotypes in early stages, while advanced Zn deficiency had the opposite effect. Compared with Zn-sufficient plants, 17-day-old Zn-deficient plants of genotypes tolerant to Zn deficiency had a lower rate of Fe transport to shoots, while genotypes sensitive to Zn deficiency (Durati, Yallaroi) had the Fe transport rate increased by Zn deficiency. A proportion of total amount of Fe taken up that was transported to shoots increased with duration of either Fe or Zn deficiency. It is concluded that greater tolerance to Zn deficiency among wheat genotypes is associated with the increased exudation of phytosiderophores, an increased Fe uptake rate and decreased transport of Fe to shoots.
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  • 25
    ISSN: 1573-5060
    Keywords: biochemical marker ; gene location ; Lophopyrum elongatum ; Puccinia striiformis ; stripe rust ; substitution line ; Triticum aestivum ; yellow rust
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A set of T. aestivum-L. elongatum chromosome substitution lines was tested for yellow rust resistance at the seedling stage. Inheritance of the resistance and esterase-5 (Est-5) variation were studied. The results demonstrated that L.elongatum carried a new gene(s) conferring yellow rust resistance. This gene was dominant and located on chromosome 3E of L. elongatum. The biochemical locus encoding Est-5was also located on chromosome 3E, and co-segregated with theYr gene(s) in the wheat background. The transmission frequencies of chromosome 3E in 3E(3A) × CS, 3E(3B) × CS and 3E(3D) × CS hybrids were scored.None of the hybrids transmitted the alien chromosome at thetheoretical maximum rate, but the transmission frequencies ofchromosome 3E in F2 populations of 3E(3A) × CS and 3E(3D) × CS were significantly higher than in thatof 3E(3B) × CS.
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  • 26
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    Euphytica 112 (2000), S. 23-31 
    ISSN: 1573-5060
    Keywords: A granules ; B granules ; quantitative analysis ; starch quality ; triploid endosperm ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two lines of hexaploid wheat were crossed and the basic generations of parent, F1, F2 and back-cross were sown in a controlled-environment chamber. FreshF1 and back-cross grains were generated, so the material could be handled either as the standard set of basic generations on a whole-plant basis, or as an extended set on an embryo or endosperm basis. The experiment was repeated. Mature grains were harvested and the starch particle size distribution was analysed in 3284 grains from 111 plants. Means and variances were partitioned into additive, dominance and interaction components. Grains from cross-pollinations had B-granule contents between parental values, rather than of the maternal parent, indicating an involvement of the grain genotype. Quantitative models based on endosperm genotype gave a better fit to the data than those based on embryo genotype. The difference in starch B-granule content between the parents was largely due to additive genes. Dominant genes were also indicated, with the first dose in the triploid endosperm having a large effect while the second dose had little or none. Non-allelic interactions were significant in the second experiment where the use of more types of backcross made them more detectable. There were also small and significant residual effects of the maternal plant in the first experiment, attributed to the vigour of the F1 mother plant and to the cytoplasm of Sunco. Narrow-sense heritability was low, between 0.05and 0.18 depending on the generation. Transgressive segregation was not found, suggesting that all alleles tending to increase the B-granule content were found in the Sunco parent and none in ME71. There was also no detectable heterosis in this character. The results show that breeding and selection for a low B-granule content should be possible but a further reduction will require new and complementary genes.
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  • 27
    ISSN: 1573-5060
    Keywords: complementary genes ; hybrid necrosis ; spring wheat ; Triticum aestivum ; winter wheat ; winter × springwheat hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The distribution and allelic expressivity of hybrid necrosis genes (Ne 1 and Ne 2) were studied in 21 winter (mostly exotic) and 43 spring type elite wheat genotypes, by crossing them with two known testers, C 306 (Ne 1-carrier) and HD 2380 (Ne 2-carrier).Ne 1 gene was present in one north-west Himalayan winter wheat landrace, Shoure Local, but absent in the other winter as well as spring wheats. Ne 2 gene was prevalent to a much lower extent in the exotic winter wheat germplasm (31.57%) as compared to the recently developed Indian and Mexican spring wheat semidwarfs (69.80%). This may suggest that breeders have tried to preclude hybrid necrosis by selecting for non-carrier genotypes in the development of exotic winter wheats in contrast to the situation in spring wheats. Based on the degree of expression of hybrid necrosis genes in the F1 hybrids, the carrier genotypes were characterized with respect to the allelic strength of the hybrid necrosis genes. The 27 non-carrier genotypes of the two ecotypes identified in the present study have a greater potential use in future hybridization programmes so as to overcome the problem of hybrid necrosis.
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  • 28
    ISSN: 1573-5060
    Keywords: Cheyenne ; polymorphism ; RAPD ; recombinant inbred chromosome line(RICL) RFLP ; STS ; SSR ; Triticum aestivum ; Wichita
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Previously chromosome 3A of wheat (Triticum aestivum L.) was reported to carry genes influencing yield, yield components, plant height, and anthesis date. The objective of current study was to survey various molecular marker systems for their ability to detect polymorphism between wheat cultivars Cheyenne(CNN) and Wichita (WI), particularly for chromosome3A. Seventy-seven `sequence tagged site' (STS), 10simple sequence repeat (SSR), 40 randomly amplified polymorphic DNA (RAPD) markers, and 52 restriction fragment length polymorphism (RFLP) probes for wheat homoeologous group 3 chromosomes, were investigated. Three (3.9%) STS-PCR primer sets amplified polymorphic fragments for the two cultivars, of which one was polymorphic for chromosome 3A. Sixty percent of SSR markers detected polymorphism between CNN and WI of which 50% were polymorphic for chromosome 3A. Twenty percent of RAPD markers detected polymorphism between CNN and WI in general, but none of these detected polymorphism for chromosome 3A. Of the fifty-two RFLP probes, 78.8% detected polymorphism between CNN and WI for group 3 chromosomes with one or more of seven restriction enzymes and 42% of the polymorphic fragements were for chromosome 3A. These high levels of RFLP and SSR polymorphisms between two related wheat cultivars could be used to map and tag genes influencing important agronomic traits. It may also be important to reconsider RFLP as the most suitable marker system at least for anchor maps of closely related wheat cultivars.
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  • 29
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    Euphytica 111 (2000), S. 199-203 
    ISSN: 1573-5060
    Keywords: Diuraphis noxia (Mordvilko) ; protein ; Russian wheat aphid ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a perennial, serious pest of wheat (Triticum aestivum L.) in the western United States. Current methodologies used to enhance RWA resistance in wheat germplasm could benefit from an understanding of the biochemical mechanisms underlying resistance to RWA. This study was initiated to identify specific polypeptides induced by RWA feeding that may be associated with RWA resistance. The effects of RWA feeding on PI 140207 (a RWA-resistant spring wheat) and Pavon (a RWA-susceptible spring wheat) were examined by visualizing, silver-stained denatured leaf proteins separated by two-dimensional polyacrylamide gel electrophoresis. Comparisons of protein profiles of noninfested and RWA-infested Pavon and PI 140207 revealed a 24-kilodalton-protein complex selectively inhibited in Pavon that persisted in PI 140207during RWA attack. No other significant qualitative or quantitative differences were detected in RWA-induced alterations of protein profiles. These results suggest that RWA feeding selectively inhibit synthesis and accumulation of proteins necessary for normal metabolic functions in susceptible plants.
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  • 30
    ISSN: 1573-5060
    Keywords: allelic variation ; Chinese wheat ; glutenin subunit ; seed storage protein ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Variation in the electrophoretic banding patterns of high-molecular-weight (HMW) glutenin subunits of 274hexaploid wheat (Triticum aestivum) varieties from China was examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and 27 different major HMW glutenin subunits were identified. Each variety contained three to five subunits and 29different glutenin subunit patterns were observed in274 Chinese hexaploid wheats. Seventeen alleles were identified based on the comparison of subunits mobility with that previously identified in a set of standard hexaploid wheats. The Chinese hexaploid wheats exhibited allelic variation in HMW glutenin subunit composition and the variation differed from that of Japanese and hexaploid wheats of other countries.
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  • 31
    ISSN: 1573-5060
    Keywords: disease resistance ; doubled haploid ; Fusarium headblight ; genetic analysis ; Fusarium graminearum ; recombinant inbred ; Triticum aestivum ; wheat scab
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The genetic constitution of resistance to Fusarium head blight (FHB, scab) caused by Fusarium graminearum in the Chinese wheat cultivar Sumai 3 and the Japanese cultivar Saikai 165 was investigated using doubled haploid lines (DHLs) and recombinant inbred lines (RILs). Frequency distributions of DHLs derived from two F1 crosses, Sumai 3 (very resistant to resistant; VR-R) / Gamenya (very susceptible; VS) and Sumai 3 / Emblem (VS), fitted well to 1: 2: 1 (resistant: moderately resistant: susceptible) ratios for reaction to FHB in the field. It is suggested that the resistance of Sumai 3 is controlled by two major genes with additive effects. One of the resistance genes may be linked in repulsion to the dominant suppressor B1 for awnedness with recombination values 15.1 ± 3.3% in Sumai 3 /Gamenya and 21.4 ± 4.3% in Sumai 3 / Emblem. Saikai 165 is a Japanese resistant line derived from an F1 Sumai 3 / Asakaze-komugi (moderately resistant; MR). The data for RILs derived from the cross Emblem / Saikai 165, indicates that three resistance genes control the resistance of Saikai 165.
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  • 32
    ISSN: 1573-5060
    Keywords: bunt infection ; bunt resistance ; frost resistance ; Tilletia caries ; T. foetida ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In order to determine the effects of bunt inoculation on frost resistance and winter hardiness in lines containing resistance genes, the bunt [Tilletia foetida (Wallroth) Liro, T. caries (DC.) Tulasne] susceptibility of wheat lines containing bunt resistance genesBt1 to Bt10 and the effect of the year on the degree of infection were studied over six years from 1991 to 1997 in an artificial inoculation nursery. Uninoculated and artificially inoculated wheat plants were tested for frost resistance in the phytotron in 1995 and in the field in boxes in three years from 1994/95 to 1996/97. The line withBt10 was very resistant, lines with Bt5, Bt6, Bt8 and Bt9 were resistant, the line with Bt4 was moderately resistant, those with Bt2 and Bt3 were moderately susceptible, the line with Bt1 was susceptible and the line with Bt7 was very susceptible to the local bunt population in Hungary. Bunt incidence also varied over years. The frost resistance of the Bt lines was generally lower after bunt inoculation than that of uninoculated plants. The increased frost kill in inoculated plants was not correlated with the extent of varietal susceptibility to bunt. Some lines with resistance, namely those with Bt5 (1.6% infection), Bt8 (0.6%) and Bt10 (0.0%), suffered significantly greater frost kill in the young plant stage as the result of bunt inoculation. By contrast, the Bt7line had excellent frost resistance and winter hardiness but suffered the greatest extent of bunt infection, whereas the Bt6 line had good frost resistance and good bunt resistance.
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  • 33
    ISSN: 1573-5060
    Keywords: bread wheat ; breeding and environmental effects ; gene frequency ; geographical distribution ; hybrid necrosis ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Using the Information and Analytical System of Wheat Genetic Resources GRIS 3.2, the peculiarities of distribution of hybrid necrosis genes in bread wheat in different regions of the world were analyzed. Considerable variation in frequencies of the Ne1 and Ne2 genes in regions with different moisture and heat supply was revealed. A significant effect of breeding on frequency dynamics of different genotypes Ne1ne2, ne1Ne2 and ne1ne2 was confirmed.
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  • 34
    ISSN: 1573-5060
    Keywords: genetic diversity ; germplasm ; RFLP ; Triticum aestivum ; wheat breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A set of 292 accessions of common wheat (Triticum aestivum L.) representing 21 germplasm pools based on geographical or breeding program origins was assayed for RFLP diversity. Thirty cDNA and genomic DNA probes and the HindIII restriction enzyme were employed for RFLP analysis. About 61% of all 233 scored bands were present in 75% or more of the accessions. All but one of the 30 probes revealed polymorphism, and the average number of distinct patterns per probe over all accessions was 9.5.Polymorphic Information Content (PIC) values within a pool varied from 0 to 0.9 and depended on the identities of both the germplasm pool and the probe. Rare banding patterns with a relative frequency of ≤0.2 within a pool were detected. These rare patterns were more likely to occur in pools exhibiting high levels of heterogeneity. The highest level of polymorphism was observed in the Turkish landraces from Southwest Asia. The Eastern U.S. soft red winter wheat germplasm pool was more genetically diverse than the other advanced germplasm pools, and nearly as diverse as the Turkish landrace pool. RFLP-based genetic relationships between germplasm pools generally tracked expectations based on common geographical origin, breeding history and/or shared parentages. The Chinese wheat landraces from Sichuan, Tibet, and Yunnan provinces were distinct from other pools. Similarity matrices for among-pool genetic distance estimates based on either band frequencies or banding pattern frequencies showed good correlation with matrices derived from Nei and Li's mean genetic similarity estimates (r=−0.82** and r=−0.73**, respectively.
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  • 35
    ISSN: 1573-5079
    Keywords: canopy architecture ; canopy photosynthesis ; CO2 enrichment ; global change ; leaf area index ; leaf tip angle ; nitrogen stress ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The response of whole-canopy net CO2 exchange rate (CER) and canopy architecture to CO2 enrichment and N stress during 1996 and 1997 for open-field-grown wheat ecosystem (Triticum aestivum L. cv. Yecora Rojo) are described. Every Control (C) and FACE (F) CO2 treatment (defined as ambient and ambient +200 μmol mol−1, respectively) contained a Low- and High-N treatment. Low-N treatments constituted initial soil content amended with supplemental nitrogen applied at a rate of 70 kg N ha−1 (1996) and 15 kg N ha−1 (1997), whereas High-N treatments were supplemented with 350 kg N ha−1 (1996 and 1997). Elevated CO2 enhanced season-long carbon accumulation by 8% and 16% under Low-N and High-N, respectively. N-stress reduced season-long carbon accumulation 14% under ambient CO2, but by as much as 22% under CO2 enrichment. Averaging both years, green plant area index (GPAI) peaked approximately 76 days after planting at 7.13 for FH, 6.00 for CH, 3.89 for FL, and 3.89 for CL treatments. Leaf tip angle distribution (LTA) indicated that Low-N canopies were more erectophile than those of High-N canopies: 48° for FH, 52° for CH, and 58° for both FL and CL treatments. Temporal trends in canopy greenness indicated a decrease in leaf chlorophyll content from the flag to flag-2 leaves of 25% for FH, 28% for CH, 17% for CL, and 33% for FL during 1997. These results indicate that significant modifications of canopy architecture occurs in response to both CO2 and N-stress. Optimization of canopy architecture may serve as a mechanism to diminish CO2 and N-stress effects on CER.
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  • 36
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    Plant and soil 226 (2000), S. 11-19 
    ISSN: 1573-5036
    Keywords: Chlorpropham (CIPC) ; microtubules ; nuclei ; recovery ; roots ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The present ultrastructural investigation on the effects of 50 μM chlorpropham (previously called CIPC) on growing roots of wheat (Triticum aestivum (L.) Thell cv. Vergina) was undertaken to clarify the mechanism of a carbamate herbicide action in plant cells, since the wide range of responses of plant cells to carbamate herbicides is based mainly on immunofluorescence studies. Cells of control roots contained abundant microtubules both in interphase and mitotic arrays. In chlorpropham-treated roots, however, no microtubules could be detected at all, neither in dividing nor in differentiating cells. Cycling cells became binucleate, polyploid or contained incomplete cell walls, the result of inhibition of cytokinesis. In long-term drug treatments (24 h or more) the affected cells entered a new cycle, which, however, did not progress beyond mid-metaphase. The nuclei of binucleate cells initiated prophase synchronously. Small vacuoles and Golgi vesicles were trapped within the nucleoplasm of the multilobed nuclei. In roots recovering from 8 h chlorpropham treatment, cells continued to exhibit polyploid nuclei, intranuclear vacuoles and incomplete walls. Microtubules reappeared but they were sparse and lacked a definite orientation. Preprophase cells did not form normal preprophase bands of microtubules, while mitotic cells occasionally contained microtubules bound to chromosomes and converged to minipoles. It is concluded that chlorpropham disorganized directly microtubules in addition to irreversibly affecting microtubule organizing centres, which failed to further support microtubule arrays.
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  • 37
    ISSN: 1573-5036
    Keywords: plant uptake ; potassium ; potassium starvation ; radiocaesium ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Short term experiments were carried out to investigate the effect of internal tissue potassium concentration on the uptake of radiocaesium by spring wheat (Triticum aestivum cv. Tonic). The results showed that potassium starvation increased Cs influx rates by a factor of 10 compared with non-starved plants. Solution to plant tissue transfer factor (TF) values also increased by around an order of magnitude after potassium starvation treatment. The enhancement of Cs influx rates by potassium starvation could be offset by an increase in external potassium concentration: this effect is minimal at external potassium concentrations greater than approximately 200 μM (8 mg L-1). This reveals that Cs influx into plant roots is subject to control by both internal and external potassium status. The kinetics of Cs uptake by potassium in starved and non-starved plants can be described adequately by the Michaelis-Menten equation. It was shown that potassium starvation substantially reduces the Km value from approximately 28 to 6 μM, which suggests that starvation treatment increases significantly the affinity of plant roots for Cs+. Mechanisms involved in K-Cs interactions during plant uptake are discussed in this paper. Finally, the relevance of such mechanisms as determinants of radiocaesium uptake by plants growing under different ecological conditions is emphasised.
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  • 38
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    Plant cell, tissue and organ culture 60 (2000), S. 69-73 
    ISSN: 1573-5044
    Keywords: cereals ; tissue culture ; Triticum durum ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fertile, green plants were regenerated from immature inflorescence explants from each of four Canadian wheat cultivars. The cultivars were representative of four classes of Canadian wheat. Explants from immature inflorescences of three size ranges were cultured on two types of media: MSI/MSR, which contains 1650 mg l-1 NH4NO3and sucrose as a carbon source, and BII/BIR, which contains 250 mg l-1 NH4NO3and maltose as a carbon source. Regeneration from all cultivars was significantly better on BII/BIR media than on MSI/MSR media. On BII/BIR media, `AC Karma', `Plenty', and `Fielder' gave the highest number of shoots per 10 explants, where the explants were derived from immature inflorescences 5.1 to 10.0 mm in length. 'Columbus' did not regenerate on MSI/MSR medium, and regenerated poorly on BII/BIR medium. Differences were found between cultivars with regard to the number of regenerant plants produced with the best treatments: `Plenty' produced 16.1 shoots per 10 explants, `AC Karma' 12.4, `Fielder' 6.4, and `Columbus' 2.2.
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  • 39
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    Plant and soil 226 (2000), S. 275-285 
    ISSN: 1573-5036
    Keywords: arbuscular mycorrhiza ; Daucus carota ; Glomus mosseae ; Glomus intraradices ; monoxenic culture ; N uptake ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract New information on N uptake and transport of inorganic and organic N in arbuscular mycorrhizal fungi is reviewed here. Hyphae of the arbuscular mycorrhizal fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe (BEG 107) were shown to transport N supplied as 15N-Gly to wheat plants after a 48 h labelling period in semi-hydroponic (Perlite), non-sterile, compartmentalised pot cultures. Of the 15N supplied to hyphae in pot cultures over 48 h, 0.2 and 6% was transported to plants supplied with insufficient N or sufficient N, respectively. The increased 15N uptake at the higher N supply was related to the higher hyphal length density at the higher N supply. These findings were supported by results from in vitro and monoxenic studies. Excised hyphae from four Glomus isolates (BEG 84, 107, 108 and 110) acquired N from both inorganic (15NH4 15NO3, 15NO3 − or 15NH4 +) and organic (15N-Gly and 15N-Glu, except in BEG 84 where amino acid uptake was not tested) sources in vitro during short-term experiments. Confirming these studies under sterile conditions where no bacterial mineralisation of organic N occurred, monoxenic cultures of Glomus intraradices Schenk and Smith were shown to transport N from organic sources (15N-Gly and 15N-Glu) to Ri T-DNA transformed, AM-colonised carrot roots in a long-term experiment. The higher N uptake (also from organic N) by isolates from nutrient poor sites (BEG 108 and 110) compared to that from a conventional agricultural field implied that ecotypic differences occur. Although the arbuscular mycorrhizal isolates used contributed to the acquisition of N from both inorganic and organic sources by the host plants/roots used, this was not enough to increase the N nutritional status of the mycorrhizal compared to non-mycorrhizal hosts.
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  • 40
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    Genetic resources and crop evolution 47 (2000), S. 281-284 
    ISSN: 1573-5109
    Keywords: agronomic traits ; isozymes ; landrace ; Triticum aestivum ; variation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A sample of an Argentinean landrace of wheat showed considerable variation in most of the evaluated morphological and agronomic characters. However, analyses with high molecular glutenins and two isozyme systems, known to be highly polymorphic among current cultivars, revealed very little or no variation, respectively. The large difference in the observed variation between morphoagronomic and biochemical characters is discussed.
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  • 41
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    Journal of chemical ecology 26 (2000), S. 2141-2154 
    ISSN: 1573-1561
    Keywords: Allelopathy ; phenolic acids ; 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ; DIMBOA ; GC-MS-MS ; wheat ; Triticum aestivum ; weed suppression ; annual ryegrass ; Lolium rigidum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Wheat allelopathy has potential for weed suppression. Allelochemicals were identified in wheat seedlings, and they were exuded from seedlings into agar growth medium. p-Hydroxybenzoic, trans-p-coumaric, cis-p-coumaric, syringic, vanillic, trans-ferulic, and cis-ferulic acids and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) were identified in both the shoots and roots of 17-day-old wheat seedlings and their associated agar growth medium. Wheat accessions with previously identified allelopathic activity tended to contain higher levels of allelochemicals than poorly allelopathic ones. The allelopathic compounds present in the shoots generally also were identified in the roots and in the agar medium. Allelochemicals were distributed differentially in wheat, with roots normally containing higher levels of allelochemicals than the shoots. When the eight allelochemicals were grouped into benzoic acid and cinnamic acid derivatives, DIMBOA, total coumaric, and total ferulic acids, the amount of each group of allelochemicals was correlated between the roots and the shoots. Most of the allelochemicals identified in the shoots and roots could be exuded by the living roots of wheat seedling into the agar growth medium. However, the amounts of allelochemicals in the agar growth medium were not proportional to those in the roots. Results suggest that wheat plants may retain allelochemicals once synthesized. The presence of allelochemicals in the agar growth medium demonstrated that wheat seedlings were able to synthesize and to exude phytotoxic compounds through their root system that could inhibit the root growth of annual ryegrass.
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  • 42
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    Plant cell, tissue and organ culture 63 (2000), S. 35-40 
    ISSN: 1573-5044
    Keywords: anther culture ; EDTA ; ferrous ions ; ferric ions ; Hordeum vulgare ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A suitable form of iron supplement in the induction medium was found to be important for further development of induced pollen embryos in barley and wheat cultivars (genotypes), especially those providing few green plants viain vitro androgenesis. Genotypes able to regenerate many green plants were less susceptible to the lack of iron in induction medium. Although Fe-EDTA was found to be a suitable form of iron in the induction medium, androgenesis was also induced on media containing non-chelated iron (Fe2+ and Fe3+ ions). EDTA alone without iron inhibited the androgenic response even in the wheat cv. Florida, a model cultivar for androgenesis in wheat. In all barley cultivars under study including cv. Igri, a model cultivar for androgenesis in barley, EDTA alone caused an almost total suppression of androgenesis.
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  • 43
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    Euphytica 113 (2000), S. 219-225 
    ISSN: 1573-5060
    Keywords: deficiency ; genotypic variation ; iron ; nutrient efficiency ; phytosiderophore ; Triticum aestivum ; Triticum durum ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tolerance to Fe deficiency of wheat genotypes exhibiting differential tolerance to Zn deficiency is not known, even though the relationship between Fe nutrition and differential tolerance of wheat genotypes to Zn deficiency has been hypothesised frequently. In the present experiment, eight Triticum aestivum and two T. turigidum L. conv. durum cultivars were grown in nutrient solution deficient in either Znor Fe. Three indices of tolerance to nutrient deficiency were compared: relative [(-nutrient/+nutrient) × 100] shoot growth, shoot dry weight under nutrient deficiency and relative shoot/root dry weight ratio. Genotypes Aroona, Excalibur, Stilleto and Trident were classified as tolerant to both Zn and Fe deficiency, while durum wheats Durati and Yallaroi were sensitive to Zn deficiency and moderate to sensitive to Fe deficiency. Genotypes Excalibur, Stilleto and Trident come from the same breeding programme and have the common parent (line MEC3 =Sonora64//TZPP/YAQUI54) that could have been the donor of the genes for tolerance to Zn deficiency. When Fe-deficient, all wheat genotypes were severely chlorotic but kept producing shoot and root dry matter at a relatively high rate, making the relationship between the relative shoot growth and the relative leaf chlorophyll content poor. This is the first report of wheat genotypes exhibiting multiple tolerance to Zn and Fe deficiencies.
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  • 44
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    European journal of plant pathology 106 (2000), S. 837-842 
    ISSN: 1573-8469
    Keywords: Triticum aestivum ; Septoria nodorum ; Phaeosphaeria nodorum ; epidemiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The transmission of Stagonospora nodorum from four naturally infected winter wheat seedlots was quantified in controlled environment germination chambers at 9, 13, 17, 21, and 25 °C. Seedlings were harvested when the second leaf began to emerge. Coleoptiles and first seedling leaves were examined for the presence of lesions caused by S. nodorum. First leaves were incubated on Bannon's medium for 2 weeks, after which they were examined for pycnidia of S. nodorum. Transmission to the coleoptile occurred at all temperatures, but decreased from 100% to 72% as temperature increased from 9 to 25 °C. Transmission to the first leaf was less, dropping from 37% to 2% as temperature increased from 9 to 25 °C. At least 44% of infected first leaves were symptomless at all temperatures, with 96% of infected leaves showing no symptoms at 25 °C. Transmission to seedling leaves occurred over a broad temperature range. Under the high densities at which wheat is sown, a significant number of infected seedlings per unit area may originate from relatively low initial seed infection levels and transmission efficiencies.
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  • 45
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    Photosynthetica 37 (2000), S. 519-527 
    ISSN: 1573-9058
    Keywords: alanine ; aspartate ; glycine ; glycollate ; malate ; nitrate ; serine ; sugars ; Triticum aestivum ; urea ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 14CO2 uptake in leaves of wheat plants (Triticum aestivum L.) fertilized by urea or Ca(NO3)2 (25 mol m-3) was investigated. The Warburg effect (inhibition of 14CO2 uptake by oxygen) under 0.03 vol. % CO2 concentration was observed only in non-fertilized plants. Under 0.03 vol. % CO2, the Warburg antieffect (stimulation of 14CO2 uptake by oxygen) was detected only in plants fertilized by Ca(NO3)2. Under saturating CO2 concentration (0.30 vol. %), the Warburg antieffect was observed in all variants. Under limitation of ribulose-1,5-bisphosphate carboxylase/oxygenase activity (0.30 vol. % CO2 + 1 vol. % O2), the rate of synthesis of glycollate metabolism products decreased in control and urea-fertilized plants but was enhanced in nitrate-fed plants. Hence, there was an activation of glycollate formation via transketolase reaction in fertilized plants, and the products of nitrate reduction function were oxidants in nitrate-fertilized plants whereas the superoxide radical played this role in urea-fertilized plants.
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  • 46
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    Photosynthetica 37 (2000), S. 615-619 
    ISSN: 1573-9058
    Keywords: carbon based secondary compounds (CBSC) ; isoorientin ; leaf age ; litter ; phenolics ; tricin ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We compared flavonoids in green, mature, and senescing flag leaves of wheat grown under ambient (AC - 370 μmol mol-1) and elevated (EC - 550 μmol mol-1) concentrations of CO2 in a FACE (Free Air CO2 Enrichment) system. The concentrations of flag leaf flavonoids (e.g., isoorientin and tricin) decreased to one third in mature leaves, and the majoritary isoorientin almost disappeared in senescing leaves. Flavonoid concentrations increased in green well-developed flag leaves under EC (46 % isoorientin and 55 % tricin), whereas the differences disappeared in mature and senescing flag leaves. Predictions of changes in litter phenolic concentrations and their effects on decomposition rates under EC based on changes in green leaves need to be revised.
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  • 47
    ISSN: 1573-9058
    Keywords: chlorophyll fluorescence ; diphenyl carbazide ; donor side ; electron transport ; MnCl2 ; NH2OH ; photosystem ; senescence ; thylakoid protein ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in various components of photosynthetic apparatus during the 6-d dark incubation at 25 °C of detached control and DCMU-treated Triticum aestivum L. leaves were examined. The rate of photosystem 2 (PS2) activity was decreased with increase of the time of dark incubation in control leaves. In contrast to this, DCMU-treated leaves demonstrated high stability by slowing down the inactivation processes. Diphenyl carbazide and NH2OH restored the PS2 activity more in control leaves than in DCMU-treated leaves. Mn2+ failed to restore the PS2 activity in both control and DCMU-treated samples. Similar results were obtained when Fv/Fm was evaluated by chlorophyll fluorescence measurements. The marked loss of PS2 activity in dark incubated control leaves was primarily due to the loss of D1, 33, and 23 kDa extrinsic polypeptides and 28-25 kDa LHCP2 polypeptides.
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  • 48
    ISSN: 1573-9058
    Keywords: net photosynthetic rate ; soil and atmospheric drought ; stomatal conductance ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Yields of wheat in semiarid and arid zones are limited by drought, and water condition is very important at each stage of development. Studies carried out at Loess Plateau in the northwestern part of China indicated that yield of spring wheat (Triticum aestivum L.) cv. Dingxi 81-392 was reduced by 41% when subjected to water stress. The effects of two water regimens on net photosynthetic rate (P N), stomatal conductance (g s), and intercellular CO2 concentration (C i) were investigated at the jointing, booting, anthesis, and grain filling stages. Low soil moisture in comparison to adequate one had invariably reduced P N during the diurnal variations at the four growth stages. P N and g s in both soil moisture regimes was maximally reduced at midday. C i and the stomatal limitation fluctuated remarkably during photosynthesis midday depression processes, especially at the grain filling stage. Hence atmospheric drought at midday was one of the direct causes inducing stomata closure and the g s depression, but it was beneficial for maintaining stable intrinsic water use efficiency. Fluctuation in C i implicated that non-stomatal limitation also plays an important role during the period of photosynthesis midday depression. Consequently stomatal and/or non-stomatal limitation are the possible cause of the midday photosynthesis decline.
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  • 49
    ISSN: 1432-1890
    Keywords: Key words Glomus mosseae ; Hydroponics ; Nitrate uptake ; Root respiration ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Oxygen and CO2 fluxes were measured in hydroponically grown mycorrhizal and non-mycorrhizal Triticum aestivum L. cv. Hano roots. The NO3 – uptake of the plants was used to estimate the amount of root respiration attributable to ion uptake. Plants were grown at 4 mM N and 10 μM P, where a total and viable mycorrhizal root colonisation of 48% and 18%, respectively, by Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe (BEG 107) was observed. The O2 consumption and NO3 – uptake rates were similar and the CO2 release was higher in mycorrhizal than in non-mycorrhizal wheat. This resulted in a significantly higher respiratory quotient (RQ, mol CO2 mol–1 O2) in mycorrhizal (1.27±0.13) than in non-mycorrhizal (0.79±0.05) wheat. As the biomass and N and P concentrations in mycorrhizal and non-mycorrhizal wheat were the same, the higher RQ resulted from the mycorrhizal colonisation and not differences in nutrition per se.
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  • 50
    ISSN: 1432-1890
    Keywords: Key words Arbuscular mycorrhiza ; Hordeum vulgare ; Triticum aestivum ; Glomus intraradices ; Mycorrhiza-helper bacteria ; Secondary compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Colonization of Hordeum vulgare L. cv. Salome (barley)and Triticum aestivum L. cv. Caprimus (wheat) roots by the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith leads to de novo synthesis of isoprenoid cyclohexenone derivatives with blumenin [9-O-(2′-O-β-glucuronosyl)-β-glucopyranoside of 6-(3-hydroxybutyl)-1,1,5-trimethyl-4-cyclohexen-3-one] as the major constituent and to transient accumulation of hydroxycinnamate amides (4-coumaroylagmatine and -putrescine). Accumulation of these compounds in mycorrhizal wheat roots started 2 weeks after sowing together with the onset of arbuscule formation and proceeded with mycorrhizal progression. Highest levels were reached in 3- to 4-week-old secondary roots (root branches of first and higher order) characterized by the formation of vesicles. In the final developmental stages, the fungus produced massive amounts of spores, enclosing the stele of older root parts (older than 5 weeks) characterized by cortical death. In these root parts, the secondary compounds were detected in trace amounts only, indicating that they were located in the cortical tissues. Some rhizosphere bacteria tested, i.e. Agrobacterium rhizogenes, Pseudomonas fluorescens, and Rhizobium leguminosarum, markedly stimulated both fungal root colonization and blumenin accumulation, thus, acting as mycorrhiza-helper bacteria (MHB). Application of blumenin itself strongly inhibited fungal colonization and arbuscule formation at early stages of mycorrhiza development. This was associated with a markedly reduced accumulation of the hydroxycinnamate amides 4-coumaroylputrescine and -agmatine. The results suggest that both the isoprenoid and the phenylpropanoid metabolism are closely linked to the developmental stage and the extent of fungal colonization. Their possible involvement in the regulation of mycorrhiza development is discussed.
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    World journal of microbiology and biotechnology 15 (1999), S. 417-423 
    ISSN: 1573-0972
    Keywords: 15N ; nitrogen mineralization ; Pseudomonas fluorescens ; rhizosphere ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effects of an antibiotic-producing Pseudomonas fluorescens strain (F113) carrying the marker gene cassette lacZY and a marked, non-producing strain (F113G22) on the uptake of nitrogen from 15N-enriched organic residues incorporated into a sandy soil were investigated in microcosm studies. Strain F113 produces the antibiotic 2,4-diacetylphloroglucinol (DAPG), whilst its modified derivative strain F113G22 has DAPG production deleted by Tn5 mutagenesis. Uptake of nitrogen by wheat (Triticum aestivum) from 15N-enriched organic residues was estimated using stable isotope-ratio mass spectrometry of shoot and root material of 17-day-old plants. In addition, plant growth and active microbial biomass in soil were monitored. In contrast to results obtained in our previous study on pea (Pisum sativum), it was found that in wheat, inoculation with either strain F113 or F113G22 decreased the proportion of nitrogen derived from 15N-labelled organic residues incorporated into soil as compared to non-inoculated controls. It is therefore suggested that these strains decreased mineralization of organic residues in the rhizosphere of wheat, making less inorganic N (15N) available for plant uptake. The results of this study indicate that the effects of introduced Pseudomonas fluorescens strains on nitrogen mineralization in the rhizosphere are plant-species dependent, and highlight the importance of testing microbial inocula on a range of plant species.
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  • 52
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    Biologia plantarum 42 (1999), S. 119-123 
    ISSN: 1573-8264
    Keywords: anatomy ; epidermis ; heavy metals ; mesophyll ; Triticum aestivum ; vascular bundles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of 1 mM cadmium, lead and nickel on dry mass, Cd, Pb, and Ni contents, and changes in leaf structure in young wheat plants were studied. In leaves, Cd content was highest, followed by Pb and Ni, in roots Cd content was also highest, but followed by Ni and Pb. Roots accumulated considerably larger amounts of the three heavy metals than leaves. Largest reductions of leaf and root mass were obtained with Cd. Pb and Ni effects were almost equal. Ni excess had a strong negative effect on mesophyll thickness, while Cd mostly reduced the number and size of vascular bundles and vessel diameter. High Pb reduced the diameter of vessels causing their different deformations.
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  • 53
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    Biologia plantarum 42 (1999), S. 217-222 
    ISSN: 1573-8264
    Keywords: chlorophyll ; photochemical activity ; photosystem 2 ; ribulose-1,5-bisphosphate carboxylase/oxygenase ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlorophyll (Chl) a and b content, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) content and activity, and electron transport rate were measured in flag leaves of wheat genotypes Uniculm and Kalyansona, grown at suboptimal and optimal supply of nitrogen. The Chl content, RuBPCO activity, and electron transport rate were decreased due to suboptimal nitrogen supply only in Kalyansona. There was no change in the ratio of RuBPCO and photosystem 2 (PS2) activity at various stages which suggests that there was no alteration in distribution of N due to additional N supply.
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  • 54
    ISSN: 1432-0789
    Keywords: Key words Phosphate-solubilizing microorganisms ; Mussoorie rock phosphate ; Vesicular-arbuscular mycorrhizae ; Triticum aestivum ; Nutrient-deficient soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The effect of inoculating wheat (Triticum aestivum L.) with the PO4 3–-solubilizing microorganisms (PSM) Bacillus circulans and Cladosporium herbarum and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus sp. 88 with or without Mussoorie rock phosphate (MRP) amendment in a nutrient-deficient natural sandy soil was studied. In the sandy soil of low fertility root colonization by VAM fungi was low. Inoculation with Glomus sp. 88 improved root colonization. At maturity, grain and straw yields as well as N and P uptake improved significantly following inoculation with PSM or the VAM fungus. These increases were higher on combined inoculation of PSM and the VAM fungus with MRP amendment. In general, a larger population of PSM was maintained in the rhizosphere of wheat in treatments with VAM fungal inoculation and MRP amendment. The results suggest that combined inoculation with PSM and a VAM fungus along with MRP amendment can improve crop yields in nutrient-deficient soils.
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  • 55
    ISSN: 1432-2242
    Keywords: Key words Erysiphe graminis ; Powdery mildew resistance ; QTL ; Triticum aestivum ; Triticum spelta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Powdery mildew is one of the major diseases of wheat in regions with a maritime or semi-continental climate and can strongly affect grain yield. The attempt to control powdery mildew with major resistance genes (Pm genes) has not provided a durable resistance. Breeding for quantitative resistance to powdery mildew is more promising, but is difficult to select on a phenotypic basis. In this study, we mapped and characterised quantitative trait loci (QTLs) for adult-plant powdery mildew resistance in a segregating population of 226 recombinant inbred lines derived from the cross of the Swiss wheat variety Forno with the Swiss spelt variety Oberkulmer. Forno possibly contains the Pm5 gene and showed good adult-plant resistance in the field. Oberkulmer does not have any known Pm gene and showed a moderate susceptible reaction. Powdery mildew resistance was assessed in field trials at two locations in 1995 and at three locations in 1996. The high heritability (h2=0.97) for powdery mildew resistance suggests that the environmental influence did not affect the resistance phenotype to a great extent. QTL analysis was based on a genetic map containing 182 loci with 23 linkage groups (2469 cM). With the method of composite interval mapping 18 QTLs for powdery mildew resistance were detected, explaining 77% of the phenotypic variance in a simultaneous fit. Two QTLs with major effects were consistent over all five environments. One of them corresponds to the Pm5 locus derived from Forno on chromosome 7B. The other QTL on 5A, was derived from the spelt variety Oberkulmer and did not correspond to any known Pm gene. In addition, five QTLs were consistent over three environments, and six QTLs over two environments. The QTL at the Pm5 locus showed a large effect, although virulent races for Pm5 were present in the mixture of isolates. Molecular markers linked with QTLs for adult-plant resistance offer the possibility of simultaneous marker-assisted selection for major and minor genes.
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  • 56
    ISSN: 1432-2242
    Keywords: Key words Lodging ; Morphological traits ; QTL ; Triticum aestivum ; Triticum spelta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Lodging can strongly affect both the grain yield and the quality of wheat. Lodging represents a quantitative trait and is difficult to assess on a phenotypic basis. Marker-assisted selection (MAS) could therefore become an important tool in breeding for lodging resistance. In this study, we mapped and characterised quantitative trait loci (QTLs) for lodging resistance, as well as morphological traits correlated with lodging, in a segregating population of 226 recombinant inbred lines derived from the cross of the lodging-resistant wheat variety Forno with the susceptible spelt variety Oberkulmer. Lodging, plant height, leaf width, leaf-growth habit, culm stiffness, culm swinging, culm thickness, days to ear emergence and days to flowering were assessed in field trials at two locations in 1996 and at one location in 1997. Additionally, at one location weight and length parameters were also assessed. Plant height and culm stiffness explained 77% of the phenotypic variance of lodging in a multiple regression model over all three environments. QTL analysis of lodging and morphological parameters was based on a genetic map containing 230 loci with 23 linkage groups (2469 cM). With the method of composite interval mapping nine QTLs for lodging resistance were detected, explaining 63% of the phenotypic variance in a simultaneous fit. Seven of these QTLs coincided with QTLs for morphological traits, reflecting the correlations between these traits and lodging. In our population the most efficient way to improve lodging resistance would be by a combination of indirect selection on plant height and culm stiffness together with MAS on the two QTLs for lodging resistance which did not coincide with QTLs for morphological traits.
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  • 57
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    Theoretical and applied genetics 98 (1999), S. 1248-1252 
    ISSN: 1432-2242
    Keywords: Key words Wheat ; Chromosome sorting ; Chromosome isolation ; Aneuploids ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We are reporting the successful isolation of wheat chromosome arm 1DS by flow cytometry. A chromosome suspension was prepared for the 1DS ditelosomic line and the normal ‘Chinese Spring’ (CS) by chopping 2-day-old root tip meristems, synchronized by hydroxyurea, in HEPES-magnesium sulfate buffer containing propidium iodide. Chromosomes were analyzed and sorted with a FACS Vantage flow cytometer and cell sorter. An extra peak was observed in the flow karyotype of the ditelosomic line that was absent in ‘CS’. The estimated size of chromosomes from the extra peak matched with the expected size of chromosome 1DS. Chromosomes from the putative 1DS peak were analyzed by both fluorescent microscopy and N-banding analysis. A total of 571 chromosomes from two separate experiments were analyzed, and all were observed to be telosomics except for 2 which were broken. About 82% of these telosomics showed the diagnostic N-band of 1DS, the remaining were unbanded and are probably also 1DS. This strategy can also be used to sort other wheat arms.
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  • 58
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    Theoretical and applied genetics 98 (1999), S. 472-477 
    ISSN: 1432-2242
    Keywords: Key words QTL ; Ear emergence time ; Plant height ; Recombinant substitution line ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Chromosome 5A of wheat carries major gene loci for agronomic traits including the vernalization requirement (Vrn-A1) and ear morphology (Q). To determine whether the genetic variation for ear emergence time and plant height is attributable to either of these major genes as pleiotropic effects or independent QTL, we combined a RFLP map constructed from 120 recombinant substitution lines derived from a cross between ‘Chinese Spring’ (Cappelle-Desprez 5A) and CS(Triticum spelta 5A) with data collected from field trials over 3 years. For ear emergence time the main effects on flowering time were by Vrn-A1 and QEet.ocs-5A.1, the latter a QTL in the 28.6-cM Xcdo584/Q interval linked to Q by less than 10 cM. The CS(T. spelta 5A) allele at QEet.ocs-5A.1 contributed to an earlier ear emergence time by 2.7–6.0 days, which was approximately equal to the effects of Vrn-A1. For plant height, three QTLs were identified on the long arm and linked in repulsion. The CS(T. spelta 5A) allele at Vrn-A1 or closely linked to Xfba068 contributed to a height reduction of 3.5–6.1 cm, whereas both the Q allele and Qt.ocs-5A.1 allele within the Xcdo1088/Xbcd9 interval from CS(Cappelle-Desprez 5A) produced a shorter plant. When plant height was partitioned into culm length and ear length, the Vrn-A1 allele and CS(Cappelle-Desprez 5A) allele at QCl.ocs-5A.1 within the Xcd1088/Xbcd9 interval were found to contribute to a shorter culm. CS(T. spelta 5A) allele at q was a major determinant of a long ear, together with minor effects at QEl.ocs-5A.1 within the Xcdo1088/Xbcd9 interval.
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  • 59
    ISSN: 1432-2242
    Keywords: Key words Aegilops tauschii ; Triticum aestivum ; Genetic mapping ; Molecular markers ; Agronomically important genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Aegilops tauschii is the diploid D-genome progenitor of bread wheat (Triticum aestivum L. em Thell, 2n=6x=42, AABBDD). A genetic linkage map of the Ae. tauschii genome was constructed, composed of 546 loci. One hundred and thirty two loci (24%) gave distorted segregation ratios. Sixty nine probes (13%) detected multiple copies in the genome. One hundred and twenty three of the 157 markers shared between the Ae. tauschii genetic and T. aestivum physical maps were colinear. The discrepancy in the order of five markers on the Ae. tauschii 3DS genetic map versus the T. aestivum 3D physical map indicated a possible inversion. Further work is needed to verify the discrepancies in the order of markers on the 4D, 5D and 7D Ae. tauschii genetic maps versus the physical and genetic maps of T. aestivum. Using common markers, 164 agronomically important genes were assigned to specific regions on Ae. tauschii linkage, and T. aestivum physical, maps. This information may be useful for map-based cloning and marker-assisted plant breeding.
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  • 60
    ISSN: 1432-2242
    Keywords: Key words Transgenic wheat ; Triticum aestivum ; Tritordeum ; Transgene inheritance ; Marker gene stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The stability and heritability of three marker genes was investigated in a population of twelve independent transgenic cereal lines (six wheat and six tritordeum). Integration patterns, inheritance of structural transgenes and inheritance of expression were analysed in the T0 and T1 generations for all 12 lines. Transmission and expression were analysed in the T2 generation for 9 lines and in the T3 generation for the six wheat lines. Inheritance of integration patterns was highly stable, and transmission of the transgenes and inheritance of their expression followed Mendelian ratios in the majority of lines. A gradual reduction in uidA expression was observed over three generations, which was not accompanied by a similar reduction in bar expression. Some unexpected phenomena associated with transgene inheritance were also observed and are discussed.
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  • 61
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    Nutrient cycling in agroecosystems 53 (1999), S. 157-175 
    ISSN: 1573-0867
    Keywords: Brassica napus ; Cicer arietinum ; current P ; Lens culinaris ; Lupinus albus ; Lupinus angustifolius ; P concentration response ; P content response ; Pisum sativum ; previous P ; sigmoid response ; single superphosphate ; Triticum aestivum ; Vicia faba ; yield response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phosphorus (P) is a major deficiency of soils of south-western Australia (WA). The fertilizer P requirements are not known for grain legumes being evaluated for neutral to alkaline, fine textured soils in WA. To rectify this, glasshouse and field experiments were undertaken to compare the responses of several grain legume species, wheat and canola to applications of single superphosphate and the results are reported in this paper. The glasshouse experiments measured responses of dried tops, harvested at 26 to 42 days after sowing, to P that was freshly-applied (current P) and previously-applied (previous P). Responses in the glasshouse were measured using yield, P concentration and P content (P concentration multiplied by yield) of oven dried tops of the following: wheat (Triticum aestivum), canola (Brassica napus), faba bean (Vicia faba), chickpea (Cicer arietinum), lentil (Lens culinaris), field pea (Pisum sativum), albus lupin (Lupinus albus) and narrow leaf lupin (Lupinus angustifolius). Field experiments in 1994 and 1995 compared seed (grain) yield responses of faba bean, chickpea, lentil, albus lupin and wheat to applications of current P. The P was banded (drilled) with the seed while sowing at 5 cm depth. Canola and wheat produced very large yield responses to increasing applications of current P. Responses were much smaller for albus lupin, faba bean and chickpea. Responses for lentil, narrow leaf lupin and field pea, fell in between responses of the small and large seeded species. Similar trends for responses were obtained as measured using yield, P concentration, or P content. For soils treated with previous P, similar trends were observed as for current P, but differences in yield responses between species were much less marked and the response curves tended to become more sigmoid. In the field experiments, grain yield responses to current P of albus lupin and chickpea were less than that for wheat. Relative to wheat, faba bean was the most responsive grain legume to applications of current P, with lentil producing similar responses to wheat in one experiment at a newly cleared, P deficient site.
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  • 62
    ISSN: 1573-0867
    Keywords: bicarbonate-extractable soil phosphorus ; Lupinus angustifolius ; residual value ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Decreases in Colwell bicarbonate soil test P in the years after applying single (ordinary) superphosphate, and the residual value of superphosphate, was measured in a long-term field experiment on a duplex (texture contrast) soil (sand over lateritic ironstone gravel clay sand at 10–15 cm), at Wongan Hills, Western Australia, typical of many soils used to grow crops in Western Australia. Ten levels of P (0–91 kg P ha-1) were applied once only in late May to different plots in different years from 1988 to 1993. Wheat (Triticum aestivum), or lupin ( Lupinus angustifolius)) were sown in late May of each year, when the P treatments applied that year were banded (drilled) with the seed. Soil samples were collected each June to measure soil test P. Seed (grain) yields of the crops were measured each December. The residual value (RV) of P applied in previous years was calculated relative to P applied in the current year, using grain yields (RVyield) and soil test P (RVsoil). Soil test P measured on soil samples collected in June was related to yields measured in December that year to provide soil P test calibrations. Relative to P applied in the current year, soil test P decreased by between 15 to 30% for P applied one year previously, by 25 to 30% for P applied three years previously, and by 60 to 70% for P applied six years previously. Soil test P was affected by spatial variation, and it also varied in the different years, for P applied in the current year, one year previously, two years previously, etc. Compared with P applied in the current year, mean RVyield determined in the different years decreased by about 40% one year after P application, followed by a further 20% decrease for P applied two years previously, followed by a further 20% decrease for P applied three to five years previously. Relative to current P, RVsoil decreased by about 25% one year after P application, followed by a further 20% for P applied two years previously, followed by a further 10% for P applied three years ago, and followed by a further 6% for P applied four and five years ago. As measured in the different years, the soil P test calibration varied between years for P applied one, two etc. years previously. This was so even when the same cultivar of wheat was grown at the same site in different years.
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  • 63
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    Entomologia experimentalis et applicata 91 (1999), S. 403-412 
    ISSN: 1570-7458
    Keywords: aphid ; Diuraphis noxia ; Triticum aestivum ; endosymbiont ; insect-plant interactions ; phloem ; amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The feeding behavior of Diuraphis noxia Mordvilko (Homoptera: Aphididae) on susceptible hosts causes both ultrastructural and tissue level damage which may affect phloem composition. Genetic evidence suggests that endosymbiotic bacteria in most aphids overproduce limiting amino acids to benefit hosts but that D. noxia depends less on endosymbionts for these nutrients, possibly due to an enriched diet. To determine whether D. noxia feeding damage results in higher concentrations of essential amino acids, stylet exudates were analyzed from wheat (Triticum aestivum) damaged to different degrees. Comparison of samples from undamaged and damaged susceptible wheat revealed changes in amino acid composition and an increase in levels of essential amino acids, indicating a nutritionally enhanced ingesta. The changes in stylet exudates paralleled changes in leaf exudates, indicating that the effects are systemic. Feeding damage is not observed on a resistant wheat host, var. Halt, and leaf exudates from infested Halt did not show changes in amino acid composition. Mean relative growth of nymphs was significantly lower on Halt than on susceptible Arapahoe, indicating that Halt is a less suitable host. Both varieties show similar amino acid levels in non-infested samples, suggesting that D. noxia infestation does not enhance the phloem environment in Halt. This study provides evidence that aphid feeding can generate a nutritionally enhanced phloem diet.
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  • 64
    ISSN: 1570-7458
    Keywords: sieve element ; salivation ; aphid ; plant resistance ; wheat ; Sitobion fragariae ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Extended sieve element salivation (E1 waveform in the electrical penetration graph) is a characteristic activity during early sieve element punctures, particularly in resistant plants. In order to explore a chemically-mediated mechanism of resistance associated with sieve element salivation, we compared the pattern of feeding behaviour of the aphid, Sitobion fragariae (Walker), on two cultivars of the wheat Triticum aestivum L., with different concentrations of hydroxamic acids (Hx). During 24 h of electronic monitoring, aphids dedicated over 50% of the total time to phloem ingestion from the sieve elements. Total time allocated to E1 in the experiment, time to first E1 within the experiment, time allocated to E1 before a sustained phloem ingestion (E2) and the contribution of sieve element salivation to the phloem phase (E1/[E1+E2]) were significantly higher in the high-Hx cultivar. The increased salivation in plants with higher contents of Hx suggests the existence, at least in this system, of a chemically-mediated sieve element constraint.
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  • 65
    ISSN: 1573-5060
    Keywords: disease assessment ; maturity ; resistance ; Septoria tritici ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nineteen cultivars, with large differences in heading date, were evaluated for their response to septoria tritici blotch in two experimental setups in Njoro, Kenya. Due to the more or less constant temperatures during the growing season and the overhead irrigation applied the epidemic conditions were similar over the whole observation period for the early and late cultivars. In experiment 1 the cultivars were assessed for disease severity at the same moment irrespective of the developmental stage, while in experiment 2 the cultivars were assessed at the same developmental stage. Measured at the same time, the disease severity was highest in the early maturing cultivars and lowest in the late maturing cultivars (r = –0.78). When assessed at the same development stage the disease build up was independent of heading date (r = –0.10) but strongly dependent on resistance level. There were no indications that early heading cultivars were more susceptible than late heading cultivars.
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  • 66
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    Photosynthesis research 59 (1999), S. 1-7 
    ISSN: 1573-5079
    Keywords: leaf gas exchange ; ozone ; Pisum sativum ; Rubisco ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have shown that short exposure of plants to high doses of ozone decreases subsequent photosynthesis; initially by reducing carboxylation capacity. This study tests the hypothesis that this is also the primary cause of loss of photosynthetic capacity in leaves affected by development under a low level of ozone. Triticum aestivum and Pisum sativum plants were exposed from germination to ozone in air (80 nmol mol-1 for 7 hours per day, for 18 days. Leaves that had completed lamina expansion at this time were free of visible injury and light absorptance was unaffected. However, some significant changes in photosynthetic gas exchange were evident. Photosynthetic CO2 uptake at light saturation was decreased significantly by 35% in T. aestivum but was unchanged in P. sativum. The reduction in photosynthesis of T. aestivum was accompanied by a 31% decline in the maximum velocity of carboxylation measured in vivo. Decreased stomatal conductance did not contribute to this reduction of photosynthesis because there was no significant change in the stomatal limitation to CO2. Processes directly dependent upon photochemical reactions; that is, the quantum yield of CO2 uptake and capacity for regeneration of ribulose 1,5-bisphosphate were not affected by O3 fumigation in either species. This suggests that for wheat, the quantitative cause of decreased photosynthetic rate in vivo is a decrease in the quantity of active ribulose-1,5- bisphosphate carboxylase-oxygenase.
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  • 67
    ISSN: 1573-5087
    Keywords: flooding ; kinetin ; leaf relative water content ; membrane stability ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat plants, 22d. old, were exposed to wide range of soil water osmotic potential (Ψs = 0 to −1.2 MPa) induced by NaCl and CaCl2 treatments in combination with roots maintained under aerobic (drained at field capacity) or nonaerobic (flooded) conditions in the soil, and sprayed with 10 mg L−1 kinetin solution. In drained plants, not receiving kinetin, increased soil salinity resulted in appreciable inhibition of shoot growth and reduction in chlorophyll (Ch1.), soluble sugars (SS) contents and grain yield. Shoot growth, Ch1. content, soluble sugars and grain yield were significantly lower for flooded plants than unflooded analogues over the entire Ψs range. Both salinity and waterlogging synergize to increase Na+, Ca+ and Cl− accumulation in shoot tissues and to decrease the stability of leaf membranes to either dehydration (40% polyethylene glycol 6000) or heat (51 °C) stress. The ratio of K+/Na+ transported to shoots under aerobic and anaerobic conditions decreased progressively on salinization. The association between the internal mineral element concentrations was largely affected by kinetin treatment. Kinetin application ameliorated the deleterious effects of salinity and oxygen deficiency. It reduced Na+, Ca2+ and Cl− accumulation and improved K+ uptake under salinity and waterlogging stresses. Increased K+/Na+ ratio helped the plants to avoid Na+ toxicity and enhanced shoot growth and grain yield. Kinetin also reduced membrane injury by dehydration and heat stresses and improved the water status of plants under both aerobic and anaerobic conditions. The effects of single factors (Soil salinity ‘Ψs’, soil waterlogging ‘WL’ and Kinetin ‘Kin’) and their interactions (Ψs × WL, Ψs × Kin, WL × Kin and Ψs × WL × Kin) were shown by analysis of variance to be statistically significant for most parameters tested. Calculation of the coefficient of determination (η+) led to three important findings. (1) Salinity (Ψs) was dominant in affecting leaf relative water content (RWC), shoot dry mass, grain yield, stability of leaf membranes to dehydration stress and the contents of Na+, Ca2+, Mg2+ and Cl−. (2) Kinetin (Kin) had a dominant effect on the stability of leaf membranes to heat stress as well as on chlorophyll and soluble sugars contents. (3) The share of waterlogging (WL) was dominant for K+ content. It can be concluded that kinetin application helped wheat plants to grow successfully in the areas subjected to combined effects of salinity and oxygen deficiency, such as in salt marshes.
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  • 68
    ISSN: 1573-5036
    Keywords: genotypic variation ; Secale cereale ; Triticum aestivum ; Triticum durum ; zinc efficiency ; zinc deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effect of zinc (Zn) nutritional status on uptake of inorganic 65Zn was studied in rye (Secale cereale, cv. Aslim), three bread wheat (Triticum aestivum, cvs. Dagdas, Bezostaja, BDME-10) and durum wheat (Triticum durum, cv. Kunduru-1149) cultivars grown for 13 days in nutrient solution under controlled environmental conditions. The cultivars were selected based on their response to Zn deficiency and to Zn fertilization in calcareous soils under field conditions. When grown in Zn-deficient calcareous soil in the field, the rye cultivar had the highest, and the durum wheat the lowest Zn efficiency. Among the bread wheats, BDME-10 showed higher susceptibility to Zn deficiency and Bezostaja and Dagdas were less affected by Zn deficiency. Similarly to field conditions, in nutrient solution visual Zn deficiency symptoms (i.e. necrotic lesions on leaf blade) appeared to be more severe in Kunduru-1149 and BDME-10 and less severe in rye cultivar Aslim. Under Zn deficiency, shoot concentrations of Zn were similar between all cultivars. Cultivars with adequate Zn supply did not differ in uptake and root-to-shoot translocation rate of 65Zn, but under Zn deficiency there were distinct differences; rye showed the highest rate of Zn uptake and the durum wheat the lowest. In the case of bread wheat cultivars, 65Zn uptake rate was about the same and not related to their differential Zn efficiency. Under Zn deficiency, rye had the highest rate of root-to-shoot translocation of 65Zn, while all bread and durum wheat cultivars were similar in their capacity to translocate 65Zn from roots to shoots. When Zn2+ activity in uptake solution ranged between 117 p M and 34550 pM, Zn-efficient and Zn-inefficient bread wheat genotypes were again similar in uptake and root-to-shoot translocation rate of 65Zn. The results indicate that high Zn efficiency of rye can be attributed to its greater Zn uptake capacity from soils. The inability of the durum wheat cultivar Kunduru-1149 to have a high Zn uptake capacity seems to be an important reason for its Zn inefficiency. Differential Zn efficiency between the bread wheat cultivars used in this study is not related to their capacity to take up inorganic Zn.
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  • 69
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    Plant and soil 215 (1999), S. 65-72 
    ISSN: 1573-5036
    Keywords: barley ; boron deficiency ; Hordeum vulgare ; Triticum aestivum ; variation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Responses of a range of barley (Hordeum vulgare L.) genotypes to boron (B) deficiency were studied in two experiments carried out in sand culture and in the field at Chiang Mai, Thailand. In experiment 1, two barley genotypes, Stirling (two-row) and BRB 2 (six-row) and one wheat (Triticum aestivum L.) genotype, SW 41, were evaluated in sand culture with three levels of applied B (0, 0.1 and 1.0 μM B) to the nutrient solution. It was found that B deficiency depressed flag leaf B concentration at booting, grain number and grain yield of all genotypes. In barley Stirling, B deficiency also depressed number of spikes plant-1, spikelets spike-1 and straw yield. However, no significant difference between genotypes in flag leaf B concentration was found under low B treatments. Flag leaf B concentration below 4 mg kg-1 was associated with grain set reduction and could, therefore, be used as a general indicator for B status in barley. In experiment 2, nine barley and two wheat genotypes were evaluated in the field on a low B soil with three levels of B. Boron levels were varied by applying either 2 t of lime ha-1 (BL), no B (B0) or 10 kg Borax ha-1 (B+) to the soil prior to sowing. Genotypes differed in their B response for grain spike-1, grain spikelet-1 and grain set index (GSI). The GSI of the B efficient wheat, Fang 60, exceeded 90% in all B treatments. The B inefficient wheat SW 41 and most of the barley genotypes set grain normally (GSI 〉80%) only at the B+. In B0 GSI of the barley genotypes ranged from 23% to 84%, and in BL from 19% to 65%. Three of the barley with severely depressed GSI in B0 and BL also had a decreased number of spikelets spike-1. In experiment 3, 21 advanced barley lines from the Barley Thailand Yield Nursery 1997/98 (BTYN 1997/98) were screened for B response in sand culture with no added B. Grain Set Index of the Fang 60 and SW 41 checks were 98 and 65%, respectively, and GSI of barley lines ranged between 5 and 90%. One advanced line was identified as B efficient and two as moderately B efficient. The remaining lines ranked between moderately inefficient to inefficient. These experiments have established that there is a range of responses to B in barley genotypes. This variation in the B response was observed in vegetative as well as reproductive growth. Boron efficiency should be considered in breeding and selection of barley in low B soils.
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  • 70
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    Euphytica 108 (1999), S. 91-95 
    ISSN: 1573-5060
    Keywords: amylose content ; granule-bound starch synthase ; null alleles ; Triticum aestivum ; Wx loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Wx locus controls amylose synthesis in the cereal endosperm. Hexaploid wheat (Triticum aestivum L.) has the three Wx loci on chromosomes 7A ( Wx-A1), 4A (Wx-B1) and 7D (Wx-D1). To verify the effects of null alleles on reducing amylose content and determine the amylose synthesis capacity of each Wx gene independently and accurately, we produced eight possible types of recombinant lines carrying different null alleles at the Wx loci under the ‘Chinese Spring’ genetic background. Amylose content varied from 0% of the waxy ‘Chinese Spring’ to 25% of the ‘Chinese Spring’ normal type. The reducing effect of the single null alleles was the largest in Wx-B1b, and there was no significant difference between Wx-A1b and Wx-D1b. More than 3% reductions in amylose content were detected in the double null types. The results of the double null lines further demonstrated that for the capacity of amylose synthesis, Wx-B1a predominates and produces 21–22% amylose, followed by Wx-D1a (20–21%) and Wx-A1a (15–18%). These significant differences were partly correlated with variation in the amounts of the Wx proteins produced by different Wx genes. However, comparisons of the double null lines with the single null or normal lines indicated that amylose content was not linearly proportional to the number of the Wx genes, suggesting that the Wx genes act in an epistatic manner.
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  • 71
    ISSN: 1573-5060
    Keywords: Blumeria graminis ; powdery mildew ; QTL ; RFLPs ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A segregating population of doubled-haploid lines issued from the cross between the wheat (Triticum aestivum L. em. Thell) cultivars Courtot, resistant to several isolates of powdery mildew (Blumeria graminis DC. f. sp. tritici Em. Marchal), and Chinese Spring (susceptible) was used to map Mlar, a gene carried by Courtot and conferring resistance to this pathogen. The assignation of Mlar using monosomic lines of Courtot was confirmed by the mapping analysis. Mlar was located on the short arm of the chromosome 1A, in the vicinity of the locus XGli-A5 coding for storage proteins. This result was in accordance with those demonstrating that Mlar was an allele of the Pm3 locus (Pm3g), a gene also involved in the resistance to powdery mildew.
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  • 72
    ISSN: 1573-5087
    Keywords: cortical fibre cell ; gibberellic acid ; spring wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The role of gibberellic acid (GA) in differentiation and secondary cell-wall deposition of fibre cells of spring wheat (Triticum aestivum) culms was studied using applications of GA and chlormequat (a GA biosynthesis inhibitor). In certain genotypes, higher GA levels may increase the number of cortical fibre cell files by changing cell fate from parenchyma to fibre, and induce thicker secondary cell-walls.
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  • 73
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    Plant growth regulation 28 (1999), S. 129-132 
    ISSN: 1573-5087
    Keywords: dormancy ; Lactuca sativa ; lettuce seeds ; Brassica napus ; rapeseed ; combustion products ; Salix viminalis ; Themeda triandra ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In darkness, dormancy was imposed on seeds of lettuce (Lactuca sativa L. cv. Grand rapids) by high temperature and on seeds of oilseed rape (Brassica napus L. cv. Apex) by osmotic stress using polyethylene glycol (PEG 8000). In both cases, dormancy was broken by incubating the seeds in aqueous extracts of combustion products from Salix viminalis wood chips or Themeda triandra leaves. Dormancy of rapeseed, but not lettuce, was also broken by a solution of smoke from burnt straw of Triticum aestivum. The greatest stimulation from burnt vegetation was achieved with an aqueous extract of pyrolysed willow wood chips, which had been subjected to temperatures of up to 800 °C during combustion in a down-draught gasifier. This suggests that some biologically active substances obtained from combustion of plant tissues are highly heat-stable.
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  • 74
    ISSN: 1573-5060
    Keywords: allelic variation ; glutenin subunit ; Japanese Norin variety ; seed storage protein ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seed storage proteins of 131 Japanese Norin wheat (Triticum aestivum) varieties were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis to determine allelic make-up in varieties at each of three loci that control high-molecular-weight (HMW) glutenin subunits. Three alleles were identified at the Glu-A1 locus, six at the Glu-B1 locus and five at the Glu-D1 locus. Twenty-four different, major glutenin HMW subunits were identified and each contained three to five subunits and seventeen different glutenin subunit patterns were observed for 19 subunits in the 131 Japanese Norin varieties. Fourteen alleles were identified by comparison of subunit mobility with that previously found in hexaploid wheat. Japanese Norin varieties showed a specific pattern of allelic variation in glutenin HMW subunits, different from that of Chinese and other country common wheats in allelic frequency at Glu-1 loci.
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  • 75
    ISSN: 1573-5036
    Keywords: boron ; genotypic difference ; sterility ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two pot experiments at the Plant Environment Laboratory (PEL), Reading, UK investigated sterility, boron (B) accumulation and B partitioning of wheat cultivars grown with limited B in the growing medium. The first experiment evaluated nine cultivars of spring wheat with diverse field responses to low available soil B, supplied with or without 20 μM B. A second experiment examined the response of a susceptible (SW-41) and a tolerant (Fang-60) cultivar to B-deficiency. These cultivars were supplied with either 20 μM B from sowing to flag leaf emergence and no added B thereafter, or 20 μM B from sowing to maturity. When B was not supplied in the nutrient solution, the number of grains ranged from 4 per ear (cv. BL-1135) to 32 per ear (cv. BL-1249) and sterility of competent florets ranged from 39% to 93%. Boron concentration in the flag leaf at anthesis did not differ greatly when the growing medium contained limited B, but differences between cultivars were evident when B was unlimited. Tolerance of B-deficiency was not related to the B concentration in the flag leaf. Some cultivars produced viable pollen and set grains while others failed to do so at similar B concentrations in the flag leaf. The two contrasting cultivars did not differ much in their pattern of B partitioning when B supply was restricted from flag leaf emergence onwards. Similarly, little evidence was found that the tolerant cultivars translocated B from their leaves, roots or stems when the supply in the growing medium was restricted. The proportion of total B partitioned in different organs was the same irrespective of B supply and cultivar. On average, leaves contained 68% of the total B content in the whole plant compared to 16% in the roots, 10% in the ears and only 6% in the stems. Tolerant or susceptible cultivars of wheat could not be distinguished based on the B concentration and B content of the flag leaf.
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    Plant cell, tissue and organ culture 59 (1999), S. 151-154 
    ISSN: 1573-5044
    Keywords: Ne1 ; Ne2 ; necrotic hybrid ; Triticum aestivum ; viable seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hybrid necrosis in wheat is a problem for gene transfer in wheat breeding. Hybrid necrosis occurs due to dominant complementary interaction of two genes, Ne1 and Ne2. A cross between wheat (Triticum aestivum L.) varieties C306 (drought tolerant, Ne1 carrier) and WL711(high yielding, Ne2 carrier) produced necrotic F1 hybrids, which died before ear emergence and produced no seeds. To overcome the problem of hybrid necrosis, ears enclosed in the leaf sheath were taken and cultured to maturity in liquid medium containing 5% sucrose and 0.04% glutamine. The necrotic hybrids produced only a few seeds per ear compared to parents, but individual grain weight was similar in the hybrid and the parents. The F1 ear culture study has been repeated for three years and F2 seeds obtained. In 1996–97, the cultured ears of F1 hybrids produced 62 seeds, of which only 52 showed germination and were grown under normal field conditions. Out of the 52 seeds, 50% were non-necrotic and showed segregation for various physiological traits. The results reveal that hybrids ears had the potential to form viable seeds. Culturing of wheat ears before ear emergence and production of viable F2 seeds from necrotic hybrids is a simple and efficient method for overcoming the problem of hybrid necrosis.
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    Plant cell, tissue and organ culture 57 (1999), S. 207-210 
    ISSN: 1573-5044
    Keywords: biolistics ; gene expression ; haploid ; transformation ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using the PDS-1000/He Biolistic® Particle Delivery System, the microprojectile travel distance, rupture disk pressure and DNA/gold particle concentrations were assessed in order to optimise short and longer-term β-glucuronidase reporter gene expression in microspore-derived embryos of wheat. The effects were also evaluated of using sterile filter paper to support explants and treatment with a high osmoticum medium (0.2 M mannitol/0.2 M sorbitol or 0.4 M maltose). In the optimised procedure, wheat microspore-derived embryos (MDEs), were placed on filter paper and incubated on medium containing 0.4 M maltose, for 4 h pre- and 45 h post-bombardment. Five μl pAHC25 (0.75 mg ml-1 in TE buffer) was precipitated onto 25 μl gold particles (60 mg ml-1 in sterile water), using 20 μl spermidine (0.1 M) and 50 μl CaCl2 (2.5 M). The particles were centrifuged and resuspended in 75 μl absolute ethanol prior to the preparation of 6 macrocarriers. A microprojectile travel distance of 70 mm, a rupture pressure of 1300 p.s.i., and a vacuum of 29′′ Hg were employed. Maltose at 0.4 M in the support medium was the most important factor influencing GUS activity in bombarded tissues. GUS activity, 1 day post-bombardment, reached 52 ± 17 GUS-positive foci/MDE (mean ± s.e.m, n=3), with 17 ± 4 foci/MDE at 15 days, giving a 3.0-fold increase (p〈0.05) compared to expression in MDEs bombarded on medium without a high osmoticum treatment.
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  • 78
    ISSN: 1573-5109
    Keywords: Aegilops tauschii ; hairy auricles ; hairy leaf sheath ; inheritance ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inheritance of genes for hairy auricles and hairy leaf sheath of Ae. tauschii in hexaploid wheat backgrounds (synthetic hexaploid wheat and common wheat varieties) was analyzed. The results indicated that hairy auricles and hairy leaf sheath of Ae. tauschii can be transferred and are expressed in hexaploid wheat. In a synthetic hexaploid wheat ('Ae. tauschii' 188) hairy auricles was proved to be controlled by a single dominant gene derived from Ae. tauschii, which was different from the Pa gene located on chromosome 4BS of common wheat. The hairy leaf sheath phenotype of 'Altar 84/Ae. tauschii 188' was also controlled by a single dominant gene derived from Ae. tauschii, which is obviously different from the Hls gene in T. dicoccoides. We suggest to designate the Ae. tauschii genes for hairy auricles and hairy leaf sheath as Pa2 and Hls2, respectively; such genes could be used as useful genetic markers in common wheat.
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  • 79
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    Genetic resources and crop evolution 46 (1999), S. 469-475 
    ISSN: 1573-5109
    Keywords: foliar blight ; germplasm ; resistance ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract One thousand three hundred and eighty-seven spring wheat germplasm (Triticum aestivum L.) lines belonging to the Indian and CIMMYT wheat programmes were evaluated for their tolerance to foliar blight disease for three consecutive years i.e., from 1994 to 1997. Disease severity at six different growth stages, beginning from tillering to late milk stage, was recorded. None of the genotypes showed immunity to the disease. Of 43 lines showing resistant reaction, a major proportion (25) was represented by CIMMYT material. Comparatively, Indian germplasm lines tended to be more susceptible at more advanced growth stages. Area Under Disease Progress Curve (AUDPC) and Apparent Infection Rate (r) values of resistant lines were much lower than those of susceptible ones, but lower AUDPC in some of the resistant lines did not correspond to a lower 'r' value. Most of the resistant lines were derived from Seri, Myna, Bau, kauz, Hork 's' and Aegilops tauschii Coss.
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  • 80
    ISSN: 1573-1561
    Keywords: Aphid ; experience ; probing behavior ; sieve elements ; salivation ; cell punctures ; hydroxamic acids ; EPG ; Sitobion fragariae ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We hypothesized that aphids after previous exposure to hydroxamic acids (Hx), a family of secondary plant compounds deleterious to aphids, are able to reduce their subsequent exposure to them. This hypothesis was tested by evaluating the time to produce salivation into a sieve element (SSE) by the aphid Sitobion fragariae on seedlings of two wheat cultivars of Triticum aestivum differing in their concentration of Hx. The total time to produce a first SSE was significantly longer in the high-Hx cultivar; however, the subsequent, second SSE (first SSE after interruption of probing) in this cultivar was significantly reduced, reaching the level observed in the low-Hx plants. Therefore, a strategy to reduce the exposure to secondary compounds was observed only in the second SSE in high-Hx plants. When the experimental plant was replaced by a new unattacked plant after the first SSE, aphids did not change the behavior described, thus excluding an aphid-induced plant susceptibility. The number of cell punctures and accumulated duration was not affected by previous exposure to Hx, either in low or high Hx cultivars. Total time and pathway time but not cell punctures, seem to be the variables affected by previous exposure to Hx.
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  • 81
    ISSN: 1618-2545
    Keywords: BLB light ; conidiogenesis ; Fusarium globosum ; subtropical Japan ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The second report ofFusarium globosum is based on strains isolated from wheat in Ishigaki Island, Okinawa, in subtropical Japan. Morphological features of the Japanese isolates are described. These strains show different reactions in conidiogenesis to light conditions. Under continuous BLB light, falcate sporodochial conidia are typically induced, but production of aerial globose conidia is suppressed. In two of the strains, clavate conidia became longer under BLB light. Application of both, complete darkness and continuous BLB light, is recommended as standard light conditions to cultureFusarium isolates.
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  • 82
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    Euphytica 105 (1999), S. 125-131 
    ISSN: 1573-5060
    Keywords: disease resistance ; inheritance ; Karnal bunt ; Neovossia ; Tilletia indica ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inheritance of resistance to Neovossia indica was studied in a Triticum aestivum line HD 29. To overcome the influence of environment on disease expression, the study was conducted by extensive evaluation of advanced generation (F8) recombinant inbred lines (RILs) developed by single seed descent from the cross WL 711 (susceptible) × HD 29 (resistant. The results suggested that HD 29 possesses three major genes for resistance to isolated Ni7 and two genes for resistance to isolate Ni8. One of the two genes controlling resistance to Ni8 is common with one of the genes conferring resistance to Ni7. These observations have important implications in breeding for Karnal bunt resistance.
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  • 83
    ISSN: 1573-5060
    Keywords: C-banding ; chromosome additions ; chromosome substitution ; Elymus tsukushiense ; homoeology ; in situ hybridization ; RFLP ; Roegneria kamoji ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Elymus tsukushiense Honda (syn. Roegneria kamoji C. Koch) (2n = 6x = 42, StsStsHtsHtsYtsYts) is a hexaploid species, distantly related to bread wheat Triticum aestivum L. em Thell (2n = 6x = 42, AABBDD). Apart from the delineation of evolutionary relationships, this species is a potential source of resistance to scab, a devastating disease of wheat caused by Fusarium graminearum Schw. A standard C-banded karyotype was established identifying all 21 chromosome pairs of E. tsukushiense. By using C-banding and genomic in situ hybridization analyses, three wheat-E. tsukushiense chromosome addition lines, one ditelosomic addition line, and one disomic substitution line were identified in BC2 progenies from wheat × E. tsukushiense hybrids. Twenty DNA markers specific for the seven homoeologous groups of the Triticeae were used to determine the homoeology of the added E. tsukushiense chromosomes. The E. tsukushiense chromosomes in the addition lines NAU702, NAU703, and NAU701 were identified as belonging to homoeologous groups 1, 3, and 5, and thus, were designated as 1Ets#1, 3Ets#1, and 5Ets#1, respectively. NAU751 was identified as a disomic substitution line with chromosome 3A of wheat replaced by chromosome 3Ets#1. Line NAU702 has a high level of resistance to scab and will be used in chromosomal engineering and development of improved wheat germplasm for scab resistance breeding.
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  • 84
    ISSN: 1573-5060
    Keywords: 1BL/1RS ; bread-making quality ; prolamins ; wheat-rye translocations ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The allelic variation of prolamin loci was studied in three F2 progenies from three crosses between the 1BL/1RS cultivar Triana and Yécora Rojo, Pavón and Florence Aurora, cultivars without the translocation. According to the 1:2:1 theoretical proportions observed in the allelic variants of the Glu-B3/Gli-B1 loci of the parent without the translocation, the inheritance as a block of the rye chromosome arm was confirmed. A group of F3-F4 recombinant lines, developed from these crosses was evaluated using the SDS-sedimentation test and the mixograph and alveograph tests. The presence of the 1BL/1RS translocation was not associated with significantly lower grain protein content values or with the optimum mixing time in the mixograph of the genotypes. The effect of the 1BL/1RS translocation on most of the quality parameters was highly dependent on the genetic pool. Significant increases in gluten strength and better mixing properties associated with the presence of some alleles of the Glu-A1, Glu-A3/ Gli-A1 and Gli-D2 loci were detected. The additivity and the interaction of prolamin gene effects with the rye translocation in the 1BL/1RS lines and its possible use in plant breeding are discussed.
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  • 85
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    European journal of plant pathology 105 (1999), S. 917-925 
    ISSN: 1573-8469
    Keywords: ergosterol ; detached glumes ; interaction ; Mycosphaerella graminicola ; Phaeosphaeria nodorum ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Interactions between Stagonospora nodorum and Septoria tritici were studied. Results from a detached glume experiment indicated that the interaction may be isolate-dependent, as it was shown that the interaction between the two pathogens may be beneficial or antagonistic depending on the isolate of each pathogen present. The number of spores produced by both pathogens was significantly greater when an aggressive isolate of S. tritici was mixed with a non-aggressive isolate of S. nodorum, whereas the number of spores produced by both pathogens was significantly less when two non-aggressive isolates were mixed. There was a significant reduction in disease level when S. tritici was applied prior to S. nodorum, compared to vice versa in the growth chamber. Results from growth chamber and field studies showed that S. nodorum produced significantly more spores when both pathogens were present together. It is concluded that S. tritici has a stimulatory effect on spore production by S. nodorum. However, there was a reduction of S. tritici spores observed in the dual inoculation treatments, suggesting that S. nodorum inhibits S. tritici.
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  • 86
    ISSN: 1573-9058
    Keywords: D1 protein ; diphenylcarbazide ; oxygen evolving complex ; scavengers ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Irradiation of thylakoid membranes at 40 °C resulted in complete inhibition of photosystem (PS) 2 activity measured as 2,6-dichlorophenol indophenol (DCIP) photoreduction either in the absence or presence of 1,5-diphenylcarbazide (DPC). Concomitant with the inactivation of PS2 activity, several thylakoid proteins were lost and high molecular mass cross-linking products appeared that cross-reacted with antibodies against proteins of PS2 but not with antibodies against proteins of other three complexes PS1, ATP synthase, and cytochrome b6f. Irradiation of thylakoid membranes suspended in buffer of basic pH or high concentration of Tris at 25 °C resulted in the formation of cross-linking products similar to those in thylakoid membranes irradiated at 40 °C. Presence of radical scavengers and DPC during the high temperature treatment prevented the formation of cross-linking products. These results suggest the involvement of oxygen evolving co mplex (OEC) in the formation of cross-linking between PS2 proteins in thylakoid membrane irradiated at high temperature.
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  • 87
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    Photosynthetica 36 (1999), S. 433-440 
    ISSN: 1573-9058
    Keywords: antibody ; polyacrylamide gel electrophoresis ; protease ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Exposure of thylakoid membranes to high temperature in dark leads to the degradation of D1 protein. Maximum degradation of D1 protein occurred at 45 °C. Using N-terminal specific D1 antibody, a 23 kDa fragment of D1 protein was detected. The degradation of D1 protein could be prevented both by radical scavengers and inhibitors of serine protease and metallo-protease. These results suggest that degradation of D1 protein during exposure of thylakoid membranes to high temperature in dark is catalyzed by protease.
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  • 88
    ISSN: 1573-9058
    Keywords: diurnal variation ; photoinhibition ; photosystem 2 reaction centres ; state transition ; trans-thylakoid membrane proton gradient ; Triticum aestivum ; xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Non-photochemical quenching of chlorophyll fluorescence (qN) and its three components (qNf, qNm, and qNs) in the flag leaves of wheat grown in the field were studied by a fluorometer PAM-2000 on clear days. The diurnal variation patterns of qN in just fully extended (JFEL) and aging leaves (AL) were similar, but qNm declined markedly in JFEL while it remained at a relatively high level in AL under strong sunlight at noon. Furthermore, at midday qNf was higher than qNs in JFEL, but much lower in AL. The results show the relative contributions of different mechanisms in preventing the photosynthetic apparatus from photodamage change during leaf development.
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  • 89
    ISSN: 1573-9368
    Keywords: low molecular weight glutenin promoter ; particle bombardment ; transgene expression ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic wheat plants from specific cultivars can now be routinely engineered in many laboratories. However, our understanding of the factors controlling transgene expression and stability in wheat compared to other cereals is rather limited. Only a few promoters have been tested in transgenic wheat, and relatively little is known of their relative activities and expression parameters. In the present study, the spatial and temporal properties of one heterologous constitutive promoter and one seed‐specific wheat promoter were investigated. We generated constructs with the reporter gene gusA (β‐glucuronidase) driven by: (a) the constitutive maize ubiquitin‐1 (ubi‐1) promoter, and (b) two different‐sized fragments of the seed‐specific low molecular weight glutenin (LMWG1D1) promoter from wheat. The activities of all three promoter constructs were comparable in endosperm tissue. A detailed analysis of spatial and temporal properties of the promoters is described. Heat shock treatment of transgenic plants carrying the ubi‐1: gusA construct resulted in a significant elevation in the levels of GUS activity. The inheritance of transgene expression levels and stability was evaluated over four generations, as a function of transgene integration patterns and copy number.
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  • 90
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    Biologia plantarum 41 (1998), S. 65-73 
    ISSN: 1573-8264
    Keywords: ascorbate peroxidase ; catalase ; flavonoids ; superoxide dismutase ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In wheat seedlings (Triticum aestivum L. cv. 2329) oxidative stress caused by UV-B radiation led to lipid peroxidation of thylakoid membrane; it was expressed in term of malondialdehyde (MDA) formation. The peroxidation of lipids of thylakoid membrane in isolated chloroplasts was prevented when flavonoids quercetin and rutin were supplied into the incubation medium. The activities of superoxide dismutase, ascorbate peroxidase, and catalase increased during the first hours of UV-B exposure. A comparative study of UV-B and temperature effects showed different profiles of the antioxidant enzymes and MDA, suggesting that these two stresses have distinct sites of action. In addition to quantitative increase in flavonoids, qualitative change in flavonoid composition was also marked during UV-B stress, and a new peak at 330 nm was found as compared to control.
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  • 91
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    Biologia plantarum 41 (1998), S. 387-394 
    ISSN: 1573-8264
    Keywords: active oxygen species ; ascorbate peroxidase ; ascorbic acid ; catalase ; hydrogen peroxide ; oxidative injury ; oxidative stress ; superoxide dismutase ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of plant antioxidant systems in stress tolerance was studied in leaves of three contrasting wheat genotypes. Drought imposed at two different stages after anthesis resulted in an increase in H2O2 accumulation and lipid peroxidation and decrease in ascorbic acid content. Antioxidant enzymes like superoxide dismutase, ascorbate peroxidase and catalase significantly increased under water stress. Drought tolerant genotype C 306 which had highest ascorbate peroxidase and catalase activity and ascorbic acid content also showed lowest H2O2 accumulation and lipid peroxidation (malondialdehyde content) under water stress in comparison to susceptible genotype HD 2329 which showed lowest antioxidant enzyme activity and ascorbic acid content and highest H2O2 content and lipid peroxidation. HD 2285 which is tolerant to high temperature during grain filling period showed intermediate behaviour. Superoxide dismutase activity, however, did not show significant differences among the genotypes under irrigated as well as water stress condition. It seems that H2O2 scavenging systems as represented by ascorbate peroxidase and catalase are more important in imparting tolerance against drought induced oxidative stress than superoxide dismutase alone.
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  • 92
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    Biologia plantarum 41 (1998), S. 427-434 
    ISSN: 1573-8264
    Keywords: phloem ; rubidium ; strontium ; Triticum aestivum ; xylem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Detached wheat shoots (ear with peduncle and flag leaf) were incubated for 4 d in a solution containing 1 mM RbCl and 1 mM SrCl2 as well as 10, 40 or 160 µM NiCl2 and CoCl2. The phloem of some plants was interrupted by steam-girdling the stem below the ear to distinguish between xylem and phloem transport. The phloem-immobile Sr flowed mainly to the leaf lamina and to the glumes via the xylem. The Sr transport was not sensitive to steam-girdling. In contrast, the phloem-mobile Rb accumulated during the incubation time mainly in the stem and the leaf sheath. The Rb transport to the grains was impaired by steam-girdling as well as by elevated Ni and Co concentrations in the incubation solution indicating that Rb was transported via the phloem to the maturing grains and that this transport was affected by the heavy metals. Ni was removed more efficiently from the xylem in the peduncle than Co (but far less efficiently than Rb). It became evident that the two heavy metals can also be transferred from the xylem to the phloem in the stem of wheat and reach the maturing grains via the phloem.
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  • 93
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    Biologia plantarum 41 (1998), S. 287-292 
    ISSN: 1573-8264
    Keywords: enzyme activities ; liquid culturing ; protein ; starch ; sugars ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effect of fluoride (10 and 50 mM) on the activities of sucrose metabolizing enzymes, alkaline inorganic pyrophosphatase, and transaminases in relation to the accumulation of free sugars, starch, and soluble protein was studied in detached ears of wheat cultured in a liquid medium. Culturing for 5 d in the presence of fluoride reduced the amount of grain starch whereas contents of total free sugars, particularly sucrose, and soluble protein increased. Fluoride inhibited the activities of soluble acid and neutral invertases, as well as sucrose synthase acting in the cleavage direction. Uptake of uniformly labelled 14C-sucrose or fructose was also drastically reduced by fluoride. Glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) activities also increased with fluoride addition in correspondence with an increase in soluble protein. Apparently, the wheat grain responds to fluoride-mediated disruption of carbon metabolism by a compensatory effect on nitrogen metabolism.
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  • 94
    ISSN: 1573-8264
    Keywords: Brassica napus ; ex vitro acclimation ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract The greatest growth of wheat and rape plants in vitro was reached on media with 5 or 9 % sucrose, respectively. The highest efficiency for transfer of these plants to ex vitro conditions was found at the same sucrose concentrations. The content of endogenous non-structural saccharides (glucose, fructose, sucrose, starch and fructans) increased with increasing sucrose concentration in the medium up to 10 %.
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  • 95
    ISSN: 1432-203X
    Keywords: Key words Bread wheat ; Triticum aestivum ; Tritordeum ; Tissue electroporation ; Transient gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat scutella and tritordeum inflorescences were transformed by tissue electroporation with plasmid DNA containing a β-glucuronidase (GUS) gene (gus A) under the control of the rice actin1 promoter. Factors affecting electroporation efficiency were analysed. Important factors were electroporation voltage and pulse length, the volume of electroporation buffer, the osmoticum of electroporation buffer and medium, the osmoticum of pre-electroporation culture medium, and pre-electroporation incubation time and temperature. Maximum transient gene expression was obtained with a single pulse of 550 V/cm from a 960-μF capacitor, using 200 μl of electroporation buffer, after 2–3 h culture on media with 357 mOsm for wheat scutella or 1 day on media with 222 mOsm for tritordeum inflorescences, and 0.5–1 h pre-electroporation incubation with DNA at 24 °C. Under these conditions, up to 90% of the explants showed GUS expression, and up to 149 expression signals were recorded per replicate. Electroporated explants showed high rates of survival and retained the ability to regenerate plants via somatic embryogenesis.
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  • 96
    ISSN: 1432-2242
    Keywords: Key words Aegilops triuncialis ; Triticum aestivum ; Heterodera avenae ; Cereal cyst nematode ; Resistance gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The cereal cyst nematode (Heterodera avenae) is an important root parasite of common wheat. A high level of resistance was transferred to wheat from Aegilops triuncialis (TR lines) using the cross [(T. turgidum×Ae. triuncialis)×T. aestivum]. Low fertility (3–5 viable kernels per plant) was observed during the process but the surviving hybrid plants were highly vigorous. To obtain stable resistant lines further crosses to T. aestivum were performed. The resistance in TR lines seems to be transferred from the C genome of Ae. triuncialis (genomes CCUU). Ae. triuncialis was highly resistant to the two Spanish populations of H. avenae tested, as well as to four French races and two Swedish populations. The histological analysis showed a hypersensitive reaction in the roots of a resistant TR line inoculated with the Ha71 pathotype of H. avenae, whereas well-formed syncytia were observed in the roots of the susceptible control. Resistance to the H. avenae Ha71 pathotype seemed to be inherited as determined by a single dominant factor in the crosses between resistant TR lines and susceptible cultivars.
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  • 97
    ISSN: 1432-2242
    Keywords: Key words Aegilops markgrafii ; Triticum aestivum ; Addition lines ; Chromosome markers ; Homoeology ; Wheat ; Wheat microsatellites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We describe the use of wheat microsatellites for the discrimination of Aegilops markgrafii chromosomes. Twenty out of eighty eight wheat microsatellites (WMS) tested were able to distinguish Triticum aestivum-Ae. markgrafii addition lines. Six, three, three, one and six of 18 WMS can be used as markers for single Ae. markgrafii chromosomes B, C, D, F and G, respectively. Addition line A is not available but additional bands, appearing only in Ae. markgrafii and the T. aestivum-Ae. markgrafii amphiploid and not in any of the available addition lines, indicate that three WMS detect markers for Ae. markgrafii chromosomes A. Addition line E could not be detected by any of the WMS markers applied, although the 20 WMS represented all the homologous groups of wheat. All three WMS located on the short arm of group-2 chromosomes were located on Ae. markgrafii chromosome B; three of four WMS, located on the long arm of wheat group-2 chromosomes, were specific to Ae. markgrafii chromosome G and three of four WMS, specific to group-5 chromosomes, were markers for Ae. markgrafii chromosome C, indicating the homoeology of these wheat chromosome arms with the respective Ae. markgrafii chromosomes.
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  • 98
    ISSN: 1432-2242
    Keywords: Key words RFLP analysis ; Triticum aestivum ; Genetic diversity ; Genetic similarity estimates ; Cluster analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Restriction fragment length polymorphisms (RFLPs) have been used to characterise the genetic diversity of wheat (Triticum aestivum) germplasm. One hundred and twenty-four accessions comprising all major Australian wheat varieties and lines important for breeding purposes were assayed for RFLPs with clones of known genetic location and selected to give uniform genome coverage. The objectives of this study were to determine RFLP-based genetic similarity between accessions and to derive associations between agronomically significant traits and RFLP phenotypes. Ninety-eight probes screened against genomic DNA digested with five restriction endonucleases detected a total of 1968 polymorphic fragments. Genetic similarity (GS) calculated from the RFLP data ranged from 0.004 to 0.409 between accessions, with a mean of 0.18. Cluster analysis based on GS estimates produced four groupings that were generally consistent with available pedigree information. Comparisons of the RFLP phenotypes of accessions containing disease resistance genes present on introgressed alien segments enabled the identification of specific alleles characteristic of these regions. Associations were derived for a range of stem-rust, leaf-rust and yellow-rust resistance genes. These results suggest that RFLP analysis can be used for the characterisation and grouping of elite breeding material of wheat and RFLP profiling can identify chromosome segments associated with agronomic traits.
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  • 99
    ISSN: 1432-2242
    Keywords: Key words Triticum spelta ; Triticum aestivum ; SDS-PAGE ; Acid-PAGE ; Seed storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Seed storage proteins of a few selected spelt forms and crosses have already been electrophoretically analysed by SDS-PAGE and acid-PAGE and compared with a few winter wheat cultivars. In the analyses presented here further important Central European spelt varieties were included, as well as modern winter wheat cultivars which were chosen as standards. In this study gliadin and glutenin band patterns of modern Central European winter wheat cultivars were analysed, in particular for a comparison with spelt varieties. An improved differentiation within and between the two species was obtained.
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  • 100
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    Theoretical and applied genetics 96 (1998), S. 69-75 
    ISSN: 1432-2242
    Keywords: Key words Aegilops umbellulata ; Co-linearity ; Comparative mapping ; Translocations ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A comparative genetic map of Aegilops umbellulata with wheat was constructed using RFLP probes that detect homoeoloci previously mapped in hexaploid bread wheat. All seven Ae. umbellulata chromosomes display one or more rearrangements relative to wheat. These structural changes are consistent with the sub-terminal morphology of chromosomes 2 U, 3 U, 6 U and 7 U. Comparison of the chromosomal locations assigned by mapping and those obtained by hybridization to wheat/Ae. umbellulata single chromosome addition lines verified the composition of the added Ae. umbellulata chromosomes and indicated that no further cytological rearrangements had taken place during the production of the alien-wheat aneuploid lines. Relationships between Ae. umbellulata and wheat chromosomes were confirmed, based on homoeology of the centromeric regions, for 1 U, 2 U, 3 U, 5 U and 7 U. However, homoeology of the centromeric regions of 4 U with wheat group-6 chromosomes and of 6 U with wheat group-4 chromosomes was also confirmed, suggesting that a re-naming of these chromosomes may be pertinent. The consequences of the rearrangements of the Ae. umbellulata genome relative to wheat for gene introgression are discussed.
    Type of Medium: Electronic Resource
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