ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (148)
  • wheat  (60)
  • photosynthesis  (46)
  • Zea mays  (43)
  • Springer  (148)
  • 1990-1994  (148)
  • 1992  (148)
Collection
  • Articles  (148)
Publisher
Years
  • 1990-1994  (148)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 63 (1992), S. 101-102 
    ISSN: 1570-7458
    Keywords: Cnaphalocrosis medinalis ; rice leaffolder ; Oryza sativa ; rice ; photosynthesis ; transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 5 (1992), S. 149-156 
    ISSN: 1572-8773
    Keywords: Hg2+ toxicity ; cyanobacterium ; Nostoc calcicola ; growth ; photopigments ; nucleic acids ; photosynthesis ; membrane integrity ; nutrient uptake ; enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Toxicological responses of the filamentous N2-fixing cyanobacteriumNostoc calcicola Bréb. towards Hg2+ were studied to enumerate the decisive lethal events. In low-dose, long-term experiments (0.05–0.25 μm Hg2+, 10 days), photoautotrophic growth was severely inhibited with concurrent loss of photosynthetic pigments (phycocyanin〉chlorophyll α〉carotenoids) and nucleic acids. The termination of growth after a day 4 exposure to 0.25 μm Hg2+ has been attributed to the complete inhibition ofin vivo photosynthetic activity in the cyanobacterium (O2 evolution〉14CO2 incorporation). The elevated Hg2+ concentrations irreversibly damaged the cell membrance as observed under light microscopy, and as indicated by the leakage of intracellular electrolytes and phycocyanin. In high-dose, short-term experiments (0.5–20.0 μm Hg2+, up to 6 h), thein vivo activities of selected enzymes (glutamine synthetase 〉 nitrate reductase 〉 nitrogenase) were less inhibited by Hg2+ than the uptake of nutrient ions (NH 4 + 〉NO 3 − 〉PO 4 3− ).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Mycopathologia 117 (1992), S. 157-161 
    ISSN: 1573-0832
    Keywords: Phyllachora maydis ; Monographella maydis ; Coniothyrium phyllachorae ; Zea mays ; tarspot complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The tarspot complex is caused by the interaction of Phyllachora maydis and Monographella maydis. Coniothyrium phyllachorae, possibly a mycoparasite, is found in older ascostromata of P. maydis, which always appears first causing tarspot. M. maydis follows and is responsible for the damaging “fisheye” symptom. The fisheye symptom is always associated with a tarspot in the center of the lesion, whereas 12 to 20% of the Phyllachora ascostromata remained free of M. maydis. Inoculations of maize leaves with the Microdochium anamorph of the Monographella (usually produced in lesions) failed to produce infections. Some infections with M. maydis were, however, obtained under unusual conditions in the field. Inoculations onto tarspots in the laboratory were unsuccessful, but in field experiments inoculations with conidia of M. maydis enhanced severity of the tarspot complex. Fisheye symptoms of the complex naturally appear 2 to 7 days after the manifestation of P. maydis. This is followed a week later by the appearance of M. maydis which became predominant in the lesions and is associated with empty perithecia of P. maydis. In the early stages of the tarspots pycnidia of the anamorph of P. maydis, Linochora sp., could occasionally be observed. Ascomata of M. maydis were rare in the field. Of the 36 genetic materials of CIMMYT tested, 30 developed the fisheye symptom, 4 tarspots only and 2 remained free of symptoms
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Mycopathologia 119 (1992), S. 181-190 
    ISSN: 1573-0832
    Keywords: aflatoxin B1 ; electron microscopy ; in vitro ; immature maize embryo ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Immature maize (Zea mays L.) embryos were treated with aflatoxin B1 concentrations, ranging from 0.1 μg ml−1 to 25 μg ml−1. Below 5 μg ml−1 aflatoxin B1, root and shoot elongation was not significantly inhibited. Ultrastructurally, root tip cells showed little deterioration, except a possible diffused clearing in mitochondria and plastids. As the toxin concentration was increased above 5 μgml−1, shoot, and particularly root elongation, was progressively inhibited. Associated with this, there was an apparent decrease in the ribosome population. Furthermore, membranes, particularly the vacuolar membrane, became abnormal and vacuolar distension occurred. At 20 and 25 μg ml−1, these effects were exacerbated, and mitochondria and plastid structure was disrupted. At these concentrations, there was evidence of a disruption in lipid metabolism. The results are discussed in the context of known aflatoxin effects on cellular control mechanisms and ultrastructure in animal systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 31 (1992), S. 319-329 
    ISSN: 1573-0867
    Keywords: Superphosphate ; fertilizer effectiveness ; residual value ; lupins ; oats ; wheat ; grain production ; bicarbonate-extractable soil phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a field experiment on a deep pale-yellow sand in a 600 mm per annum rainfall Mediterranean environment of south-western Australia, six levels of phosphorus (P) as superphosphate (O up to 546 kg P ha−1) were applied once only, to the soil surface, before sowing lupins (Lupinus angustifolius). The lupins were grown in a continuous arable cropping rotation with, in successive years, oats (Avena sativa), wheat (Triticum aestivum), lupins. Five such rotations were started in the experiment from 1985 to 1989. The experiment continued until the end of 1990. The relationship between lupin seed (grain) yields and the level of P applied was measured in the year of P application for five successive years (1985 to 1989). The relationship had the same general form but it varied between years, largely due to different maximum yields (yield plateaux) in each year. The residual value of superphosphate applied three years previously was measured for lupins on two occasions (1988 and 1989) relative to superphosphate applied in the current year. The residual values was different in the two years. The superphosphate applied three years previously was about 30% as effective as freshly applied superphosphate in 1988, and 12% as effective in 1989. At each harvest, the relationship between grain yield and the P concentration in the grain differed for different species. However, for each species at each harvest, the relationship was similar regardless of when the P was applied in the previous years. Thus each species had the same internal efficiency of P use curve, and yields varied only with P concentration in tissue. Bicarbonate-extractable soil P was determined on soil samples taken in mid-July of 1989 and 1990. These soil test values were related to grain yields at harvest. The relationship between yield and soil test values had the same general form but varied for different species within years and for each species between years. It also varied for each species within years depending on the year the P was applied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 31 (1992), S. 331-340 
    ISSN: 1573-0867
    Keywords: Superphosphate ; residual value ; wheat ; lupins ; soil test for phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a field experiment on a sandplain soil in a low rainfall (326 mm per annum) Mediterranean environment of south-western Australia, the effectiveness of superphosphate applied in 1986 was measured in three subsequent years relative to freshly-applied superphosphate each year, using grain (seed) yields of wheat (Triticum aestivum) and lupins (Lupinus angustifolius). The wheat and lupins were grown in rotation and both crops were grown each year starting in 1986. Bicarbonate-soluble phosphorus was determined on soil samples taken in mid June from where the P treatment was applied in 1986 only. These soil test values were related to the grain yields produced that year. For each level of superphosphate applied in 1986, soil test values decreased with increasing time from application. The relationship between grain yield and soil test values had the same general form within each year for both plant species, but varied between years. For both species, the effectiveness of superphosphate decreased by about 70–80% between the year of application and the first and second years after application, and by a further approximate 10% in the third year. The relationship between grain yield and the level of superphosphate applied became sigmoidal by 1989.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1573-0867
    Keywords: nitrogen fertilizer rate ; electroultrafiltration ; wheat ; soil test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The objective of the investigation was to examine whether there exist relationships between the optimum nitrogen fertilizer rate for winter wheat and soil nitrogen fractions extracted by electroultrafiltration (EUF) from autumn samples of the upper soil layer (0–30 cm). Optimum nitrogen fertilizer rates were derived from grain yield curves of field trials carried out with increasing nitrogen fertilizer rates on 19 different sites in 1985/86 and 1986/87. Most soils were luvisols derived from loess, two soils were brown earths and one a pararendzina. Total Nitrogen fertilizer rates were 0, 40, 80, and 120 kg N/ha applied twice before ear emergence. The final nitrogen rate at ear emergence was the same for all treatments, namely 60 kg N/ha. Optimum nitrogen fertilizer rates were derived from the grain yield curve fitted to a modified Mitscherlich equation. The optimum nitrogen fertilizer rates were correlated with the nitrogen fractions extracted by EUF. The regression equation thus obtained showed that NO 3 - , the organic N fraction (EUF Norg), and the EUF Norg-quotient each had a highly significant impact on the optimum nitrogen fertilizer rate. The higher the amounts of EUF-N extracted the lower the optimum nitrogen rate. Substituting the EUF Norg-fraction for total nitrogen concentration in the upper soil layer gave a poorer relationship between the optimum nitrogen fertilizer rate and the soil data. In absolute terms the EUF Norg-fraction had by far the greatest impact on calculating the optimum nitrogen fertilizer rate. The investigation shows that the EUF method is a suitable technique for the determination of available soil nitrogen from which optimum nitrogen fertilizer rates can be derived for winter wheat cultivated under soil and climatic conditions typical for cereal growing areas in central Europe.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 31 (1992), S. 43-49 
    ISSN: 1573-0867
    Keywords: Superphosphate ; nitrogen fertilizer ; take-all ; (Gaeumannomyces graminis) ; wheat ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat was grown continuously in soil amended with 5 levels of superphosphate and with 4 levels of urea at 3 sites. The incidence and severity of take-all, caused byGaeumannomyces graminis var.tritici, declined with increasing rates of application of both superphosphate and urea. In both years, the severity of take-all on plants receiving neither superphosphate nor urea was about 40% while at the highest level of superphosphate and urea supply the take-all severity was approximately halved at 22%. There was an increase in grain yield in response to applied superphosphate and urea to the highest level of each nutrient. There was also an increase in the 1,000-kernal weights with superphosphate and urea fertilizer application.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 27-36 
    ISSN: 1573-0867
    Keywords: Phosphorus requirement ; wheat ; oats ; barley ; lupins ; triticale ; superphosphate ; grain yield ; phosphorus in grain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The phosphorus (P) requirement for grain production of different crop species (oats (Avena sativa), barley (Hordeum vulgare), triticale (xTriticosecale), narrow-leafed lupins (Lupinus angustifolius), and sandplain lupins (L. cosentinii) was compared with wheat (Triticum aestivum) in five field experiments on different lateritic soils in south-western Australia. Seven or eight levels of superphosphate were applied at the start of each experiment. The amount of P required to produce 70% (four experiments) or 90% (one experiment) of the maximum yield was used to compare P requirements. Large differences in the P requirements of the species were obtained. On P deficient soil in 3 experiments, oats required from 50 to 70% less P than wheat, but required 40% more P on a soil with a long history of superphosphate applications. Compared with wheat, in the year of P application, barley required 50% less P in one experiment, had similar P requirements in two experiments, and required 80% more P in another experiment. In the years after P application, barley required 20% less P in two experiments. On an acidic soil triticale required from 50% to 70% less P than wheat, but on less acidic soil it required 100% more P. In the year of P application, narrow-leafed lupins required 800% more P than wheat in one experiment, and 30% more P in the other experiment. In the year of P application, sandplain lupins required 70% less P than wheat in one experiment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 185-194 
    ISSN: 1573-0867
    Keywords: Residual P ; P fixation ; Bray P ; Olsen P ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nineteen soils from the south east of the Province of Buenos Aires (Argentina) that had been fertilized with moderate amounts of P (10–40 kgP/ha) during the last 10 years were used to investigate the effect of time on the decline of P availability as measured by three soil tests (Bray 1, Bray 2, Olsen) and the null-point method. Differences in rates of P decline among soils and chemical methods were characterized by an exponential coefficient for time (b 2) in equations which describe the changes of the added P retained by the soil (Pr =ac b1 t b2). The rate of decline of P for the nineteen soils calculated for the soil test methods was ordered decreasingly as: null-point 〉 Olsen 〉 Bray 1 〉 Bray 2. The ability of the chemical methods for assessing the residual value of P for wheat growth (RV) was tested in a pot experiment on seven of the soils that differed in their individual rates of reaction with P. Differences between soils in the rate of reaction with P as measured in the laboratory by the null-point method and by the Olsen test were reflected in different residual values for P fertilizer for wheat plants. Thus the value ofb 2 for these methods was well correlated with the observed residual values. The soil properties commonly associated with the retention of P were not related to the value ofb 2 suggesting that more than one soil property may be involved in the measure ofb 2. The exponent for timeb 2 may be used as an index of the ability of the soil test to reflect the decline of P availability with time.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Aquatic sciences 54 (1992), S. 321-330 
    ISSN: 1420-9055
    Keywords: Algal pigments ; algal communities ; photosynthesis ; Lake Lugano (Lago di Lugano)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A one-year study of phytoplankton, primary production and related physical and chemical factors was made in a Swiss basin of Lake Lugano (Lago di Lugano). The chlorophylls and 12 carotenoids were analyzed with a TLC technique. The carotenoid monitoring was considered to be particularly interesting, because the role of these pigments in freshwater algae is still very poorly documented by field studies. The dependence of photosynthesis on several factors was statistically evaluated. Evidence was found of light-adaptation phenomena. The variations of photosynthetic activity and efficiency largely depended on the light regime in the few days before the field observations and on the cellular content of chlorophylls and single carotenoids, whose concentrations in their turn were closely linked with light, temperature, average cell size, and with the actual species assemblage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell reports 11 (1992), S. 567-570 
    ISSN: 1432-203X
    Keywords: Microspore ; Electroporation ; Transformation ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ability to deliver and detect reporter gene activity in maize microspores was tested. Tested expression vectors contained the chloramphenicol acetyl transferase (CAT) gene and one of the following promoter-intron combinations: 1) cauliflower mosaic virus (CaMV 35S), 2) CaMV 35S + maize alcohol dehydrogenase 1 intron 6 (Adh1-I6), 3) maize alcohol dehydrogenase 1 + intron 1 (Adh1-I1), or 4) maize ubiquitin 1 + intron 1 (Ubiq 1-I1) promoter + intron. The expression vectors were delivered into maize microspores using electroporation or polyethylene glycol (PEG). Both methods were effective for delivering free DNA into microspores. Although all four promoters were active in maize protoplasts, only two promoters were active in maize microspores. The CaMV 35S and the Adh1 promoters did not promote gene expression in maize microspore. The CaMV 35S + Adh1-I6 and Ubiq1-I1 promoters produced high levels of CAT activity in maize microspores.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 5 (1992), S. 224-226 
    ISSN: 1432-2145
    Keywords: Zea mays ; Maize ; Polyembryony
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two types of cleavage polyembryony are described in the inbred line VIR 17 of maize. Suspensorial embryony was observed to occur spontaneously. Typical cleavage of the zygotic proembryo occurred spontaneously, but could also be induced by treating the developing caryopses with 2,4-Dichlorophenoxyacetic acid (2,4-D) on the second day after pollination. 2,4-D was active as a decorelative factor also evoking the expression of totipotency in individual proembryonal cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 5 (1992), S. 227-231 
    ISSN: 1432-2145
    Keywords: Zea mays ; Maize ; Pollen-tube growth regulation ; In vitro pollination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In vitro pollen-tube growth in maize was studied using an in vitro pollination system. In the ‘cut-silk’ method, ovaries with silks were placed on medium in vitro, whereafter the silk was cut and the upper part of the silk was pollinated. Pollen tubes were not able to bridge the space between the two silk parts. Even when silk parts were tightly connected, pollen tubes still were not able to pass the cut ends and reach the lower silk part. Pollen-tube growth rates and the direction of tube growth were not influenced by the presence or absence of an ovary. Prepollination did not have any influence on pollen-tube growth rate. Measurements of pollen-tube growth rate also showed that there was no ‘population effect’, i.e. growth rate was not stimulated by pollination with an excess of pollen grains. We found that the direction in which maize pollen grew was determined only by the positioning of the silk hairs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell reports 11 (1992), S. 535-539 
    ISSN: 1432-203X
    Keywords: Zea mays ; in vitro culture ; in vitro pollen ; pollen germination ; fertilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Maturation of maize pollen was obtained in male reproductive structures cultured in vitro. Immature tassels containing microspores at the mid-uninucleate to late-binucleate stage of development were excised and spikelets, anthers, and/or isolated microspores were cultured on a medium capable of supporting pollen maturation. Microspore mitosis, culminating in the production of starch-filled, trinucleate pollen capable of germination, was observed after 7–15 days, depending on the genotype and stage at which the cultures were initiated. Up to 100%, 70%, and 20% of the cultured spikelets, anthers, and isolated microspores, respectively, produced mature pollen, which germinated, however, at different frequencies (i.e., spikelets, 50–70%; anthers, 5–10%; microspores, 〈1%). Mature kernels were produced following fertilization with pollen from cultured spikelets and anthers. These procedures provide methods for the in vitro manipulation of a significant phase of the maize life cycle.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 1432-203X
    Keywords: Zea mays ; Matrix-associated ; DNA ; repetitive sequences ; DNA loops
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to elucidate some features of the topological organization of DNA within the plant nucleus, DNA fragments involved in the attachment of the DNA loops to the nuclear matrix in maize were studied. The matrix-associated DNA from dry embryo and meristematic cells after extensive digestion with DNase I and high salt treatment was about 2% of the total DNA, sized within the range of 50 and 250 bp. This DNA was found to be enriched in repetitive DNA sequences, both for nuclei from dry embryo and meristematic cells. The loop size of the DNA in cells of Zea mays appeared to be between 5 and 25 kbp.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 13 (1992), S. 142-146 
    ISSN: 1432-0789
    Keywords: A value ; Common bean ; N remobilization ; Soil N balance ; Atom% 15N excess ; Phaseolus vulgaris ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The common bean (Phaseolus vulgaris L.) is generally regarded as a poor N2 fixer. This study assessed the sources of N (fertilizer, soil, and fixed N), N partitioning and mobilization, and soil N balance under field conditions in an indeterminate-type climbing bean (P. vulgaris L. cv. Cipro) at the vegetative, early pod-filling, and physiological maturity stages, using the A-value approach. This involved the application of 10 and 100 kg N ha-1 of 15N-labelled ammonium sulphate to the climbing bean and a reference crop, maize (Zea mays L.). At the late pod-filling stage (75 days after planting) the climbing bean had accumulated 119 kg N ha-1, 84% being derived from fixation, 16% from soil, and only 0.2% from the 15N fertilizer. N2 fixation was generally high at all stages of plant growth, but the maximum fixation (74% of the total N2 fixed) occurred during the interval between early (55 days after planting) and late podfilling. The N2 fixed between 55 and 75 days after planting bas a major source (88%) of the N demand of the developing pod, and only about 11% was contributed from the soil. There was essentially no mobilization of N from the shoots or roots for pod development. The cultivation of common bean cultivars that maintain a high N2-fixing capacity especially during pod filling, satisfying almost all the N needs of the developing pod and thus requiring little or no mobilization of N from the shoots for pod development, may lead to a net positive soil N balance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    ISSN: 1440-1703
    Keywords: Clethra barbinervis ; interspecific difference ; intraspecific variation ; photosynthesis ; SO2 resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of SO2 on the photosynthesis ofClethra barbinervis collected from a smoke-polluted area near the Ashio copper smelter in Tochigi Prefecture was compared withC. barbinervis collected from a nonpolluted district in Tsukuba, Ibaraki Prefecture andQuercus mongolica var.grosseserrata grown in a nonpolluted field in Nagano Prefecture. The plants were exposed to 0.5–1.5 p.p.m. SO2 for 90 min (short-term) and to 0.3 p.p.m. SO2 for 31–39 days (long-term). TheClethra plants from both sites had a lower intrinsic stomatal conductance and photosynthetic rate thanQuercus plants. Short-and long-term fumigation caused stomatal closure inQuercus plants, but had little effect on the stomatal conductance ofClethra plants. Under short-term fumigation, nonstomatal photosynthetic inhibition per unit of absorbed SO2 was smallest inClethra plants from Ashio. Long-term fumigation caused photosynthetic decline and visible foliar injury toQuercus plants, but had no effect onClethra plants from Ashio. Consequently,Clethra plants from Ashio had a higher photosynthetic rate thanQuercus plants after long-term fumigation. These results suggest thatC. barbinervis populations in the smoke-polluted area of Ashio had evolved high SO2 resistance connected with SO2 detoxification ability in mesophyll cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    ISSN: 1573-1561
    Keywords: Cover crops ; wheat ; Triticum aestivum ; soybean ; Glycine max ; soil extracts ; germination bioassays ; phenolic acids ; hydroxamic acids ; allelopathy ; slope analysis ; ivy-leaved morning glory ; Ipomoea hederacea ; crimson clover ; Trifolium incarnalum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The primary objective of this research was to determine if soil extracts could be used directly in bioassays for the detection of allelopathic activity. Here we describe: (1) a way to estimate levels of allelopathic compounds in soil; (2) how pH, solute potential, and/or ion content of extracts may modify the action of allelopathic compounds on germination and radicle and hypocotyl length of crimson clover (Trifolium incarnatum L.) and ivyleaved morning glory (Ipomoea hederacea L. Jacquin.); and (3) how biological activity of soil extracts may be determined. A water-autoclave extraction procedure was chosen over the immediate-water and 5-hr EDTA extraction procedures, because the autoclave procedure was effective in extracting solution and reversibly bound ferulic acid as well as phenolic acids from wheat debris. The resulting soil extracts were used directly in germination bioassays. A mixture of phenolic acids similar to that obtained from wheat-no-till soils did not affect germination of clover or morning glory and radicle and hypocotyl length of morning glory. The mixture did, however, reduce radicle and hypocotyl length of clover. Individual phenolic acids also did not inhibit germination, but did reduce radicle and hypocotyl length of both species. 6-MBOA (6-methoxy-2,3-benzoxazolinone), a conversion product of 2-o-glucosyl-7-methoxy-1,4-benzoxazin-3-one, a hydroxamic acid in living wheat plants, inhibited germination and radicle and hypocotyl length of clover and morning glory. 6-MBOA, however, was not detected in wheat debris, stubble, or soil extracts. Total phenolic acids (FC) in extracts were determined with Folin and Ciocalteu's phenol reagent. Levels of FC in wheat-conventionaltill soil extracts were not related to germination or radicle and hypocotyl length of either species. Levels of FC in wheat-no-till soil extracts were also not related to germination of clover or morning glory, but were inversely related to radicle and hypocotyl length of clover and morning glory. FC values, solute potential, and acidity of wheat-no-till soil extracts appeared to be independent (additive) in action on clover radicle and hypocotyl length. Radicle and hypocotyl length of clover was inversely related to increasing FC and solute potential and directly related to decreasing acidity. Biological activity of extracts was determined best from slopes of radicle and hypocotyl length obtained from bioassays of extract dilutions. Thus, data derived from the water-autoclave extraction procedure, FC analysis, and slope analysis for extract activity in conjunction with data on extract pH and solute potential can be used to estimate allelopathic activity of wheat-no-till soils
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 18 (1992), S. 1227-1237 
    ISSN: 1573-1561
    Keywords: Western corn rootworm ; Diabrotica virgifera virgifera ; Coleoptera ; Chrysomelidae ; bacteria ; carbon dioxide ; pheromone ; semiochemicals ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract FemaleDiabrotica virgifera virgifera LeConte were allowed to choose between oviposition substrates that were and those that were not associated with potential sources of semiochemicals. Females deposited over five times more eggs on moist towelettes that were treated with homogenates of female abdomens than on towelettes treated with distilled water. Similar results were obtained when screening separated the homogenates from the towelettes, indicating that odors alone could elicit the response. In contrast, females did not choose towelettes that had previously been used for oviposition or towelettes containing eggs over unused towelettes. Further tests with homogenates of abdomens and a bacteriostatic agent (sorbate) indicated that the females were probably responding to bacterial odors rather than an oviposition-enhancing pheromone. Four strains of bacteria were isolated from a homogenate of female abdomens; females deposited 4 to 16 times more eggs on substrates with odors of the bacteria than on substrates with odors of uninoculated nutrient agar. In no-choice tests, bacterial odors did not increase the number of eggs deposited per female beetle; however, in choice tests with dishes that tended to retain any beetles that entered, there were more eggs per female (but not more beetles) after 24 hr in dishes with bacterial odors than in those without the odors. Females also chose dishes with odors of excised maize (Zea mays L.) roots or elevated levels of carbon dioxide over “control” dishes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 18 (1992), S. 423-427 
    ISSN: 1573-5028
    Keywords: Hordeum vulgare L. ; CM protein ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The primary structure of the insect α-amylase inhibitor CMa of barley seeds was deduced from a full-length cDNA clone pc43F6. Analysis of RNA from barley endosperm shows high levels 15 and 20 days after flowering. The cDNA predicts an amino acid sequence of 119 residues preceded by a signal peptide of 25 amino acids. Ala and Leu account for 55% of the signal peptide. CMa is 60–85% identical with α-amylase inhibitors of wheat, but shows less than 50% identity to trypsin inhibitors of barley and wheat. The 10 Cys residues are located in identical positions compared to the cereal inhibitor family with a Pro-X-Cys motif present in all.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    ISSN: 1573-5028
    Keywords: geminivirus ; agroinfection ; Zea mays ; large intergenic region (LIR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maize streak virus as well as other geminiviruses contain a potential hairpin structure with the conserved sequence TAATATTAC in the loop. We assessed the possible involvement of this structure in replication and symptom induction of the virus. A series of insertion and deletion mutants were analyzed by agroinfection. Deletion of the hairpin or insertions in the conserved sequence abolished symptom development. Viral DNA could not be detected in the infected tissue. However, a mutant with a point mutation in the ‘conserved’ sequence, isolated after inoculation of maize plants with an insertion mutant, was able to replicate and to induce symptoms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    ISSN: 1573-5028
    Keywords: gene duplication ; photosynthesis ; RFLP ; Southern blots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A second locus (Lhb1B) encoding Photosystem II Type I chlorophyll a/b-binding (CAB) polypeptides was identified in Arabidopsis thaliana. This locus carries two genes in an inverted orientation. The predicted sequences of the polypeptides encoded by these two genes show substantial divergence in their amino termini relative to each other and to the proteins encoded by the three Lhb1 CAB genes previously characterized [10], but little divergence within the predicted primary structure of the mature protein. DNA probes derived from seven additional types of tomato CAB genes, encoding chlorophyll a/b-binding polypeptides of several antenna systems of the photosynthetic apparatus, were tested against A. thaliana. Each of these hybridized in Southern blots to unique DNA fragment(s), demonstrating the existence of each of these different types of CAB genes in the genome of A. thaliana. The number of genes encoding each CAB type in A. thaliana was estimated to be similar to that of tomato.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 20 (1992), S. 481-491 
    ISSN: 1573-5028
    Keywords: photosynthesis ; cytochrome b 6 ; gene regulation ; genome mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genes encoding the photosynthetic cytochrome b 6 (petB) and subunit 4 (petD) have been cloned and sequenced from the unicellular, photoheterotrophic, transformable cyanobacterium Synechococcus sp. PCC 7002, formerly designated Agmenellum quadruplicatum. The gene arrangement was found to be similar to that reported in the cyanobacterium Nostoc PCC 7906. The DNA and derived protein sequences were compared to chloroplast and the other cyanobacterial sequences. By pulsed-field electrophoresis, the petBD operon and the petCA operon, encoding the Rieske iron-sulfur protein and cytochrome f, were found to be located on separate, unlinked,Not I-digested DNA fragments. ThepetBD operon was found on the third largest Not I fragment (NC-325) while the petCA operon was found on the second largest Not I fragment (NB-370). These results suggest the two operons are not in proximity. The 1.35 kb transcript was shown to be light-regulated. Transcripts from cells grown under constant illumination showed a decrease in petB transcript levels to undetectable levels within 2 h after the cells were placed in the dark. Upon reillumination, transcript levels rose to three-fold over that seen initially under constant illumination.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    ISSN: 1573-5028
    Keywords: cortex ; developmental regulation ; in situ hybridization ; organ-specific gene expression ; roots ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A near full-length cDNA clone (pZRP3) corresponding to an mRNA that accumulates specifically in roots of maize was isolated. The ZRP3 mRNA is ca. 600 nucleotides in length. The amino acid sequence of the predicted polypeptide is rich in leucine (16%), proline (11%), and cysteine (8.5%). The zrp3 gene appears to be expressed exclusively in roots, whereas other ZRP3-related genes are expressed in additional organs of the maize plant. In situ hybridization shows that ZRP3 mRNA accumulation is largely confined to the cells of the cortical ground meristem. Furthermore, accumulation of this mRNA occurs within a distinct subset of cortical cells, the inner three to four cell layers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 20 (1992), S. 849-856 
    ISSN: 1573-5028
    Keywords: GA regulation ; thiol-protease promoter ; wheat ; aleurone ; particle gun
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A wheat gene (A121) encoding a protein with sequence similarity to mammalian cathepsin B is regulated by gibberellic acid (GA) in aleurone layers of germinating grains. To analyse the mechanism of A121 regulation, its promoter was fused to the β-glucuronidase reporter gene (GUS) and introduced by micro-projectile bombardment into aleurone layers of oat. With 2.3 kb of promoter sequence, the GUS expression was enhanced by GA treatment. This effect was reversed by abscisic acid (ABA). This result showed for A121, like the α-amylase genes, that the regulation by GA and ABA was at the level of transcription. The GA responsiveness of the promoter was retained with as little as 276 bp of promoter sequence. Sequence comparison with a GA responsive promoter of an α-amylase gene identified the conserved element GCAACGGCAACGATGG which is required intact for full expression of both promoters. However, there was no identifiable similarity in the cathepsin-like promoter with the GA-responsive element of α-amylase promoters with the consensus sequence TAACAAA, suggesting that GA affects more than one mechanism of transcriptional control.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 20 (1992), S. 991-995 
    ISSN: 1573-5028
    Keywords: retrotransposon-like element ; sequence analysis ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract WIS-2-1A, a 8624 bp insertion in the Glu-1A-2 locus of chromosome 1A of wheat, consists of two 1755 bp long terminal repeats enclosing a 5114 bp internal region. No long open reading frames could be found, but inspection of the predicted amino acid sequence showed regions with homology to retrotransposon structures, including a methionine tRNA initiator binding site, a nucleotide binding domain, a protease, an integrase and a polymerase. DNA replication errors have resulted in frame-shifts in the protein coding region, suggesting that retrotransposition of WIS-2-1A, if it occurs, must be mediated by trans-acting factors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 20 (1992), S. 1159-1168 
    ISSN: 1573-5028
    Keywords: DNA polymerase ; germination ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three different DNA polymerase activities can be resolved by passing a protein extract from 24 h imbibed maize axes through DEAE-cellulose. These activities have been numbered 1, 2 and 3, according to their elution order. One of them, DNA polymerase 2, elutes at 100–120 mM phosphates. This enzyme was further purified by passing it through Heparin-Sepharose, Sephacryl S-300 and DNA cellulose. Purification was nearly 5000-fold. The enzyme needs Mg2+, is stimulated by K+, has an optimum pH of 7.0 and its optimum temperature is 30–37 °C. Specific inhibitors for different types of polymerases, such as aphidicolin, dideoxythymidine triphosphate and N-ethyl maleimide, gave intermediate values of inhibition, making impossible the definition of the type of enzyme purified by its inhibitory pattern. SDS-PAGE indicated the presence of several bands of molecular masses of 28–40, 56 and 15 kDa. Most of these bands could be visualized when proteins from crude extracts were analyzed by western blot, using an antibody against calf thymus DNA polymerase α. A high molecular mass (around 500 kDa) was calculated by western blot of native gels using the same antibody. Finally, specific activity of this enzyme increased 100-fold during maize germination whereas polymerase 3 virtually did not increase. Furthermore, immunoprecipitation experiments with the antipolymerase α-antibody showed a decrease in DNA polymerase activity by 70%. The possibility that polymerase 2 is a replicative enzyme is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 18 (1992), S. 847-849 
    ISSN: 1573-5028
    Keywords: cDNA ; nucleotide sequence ; glycine-rich proteins ; chemical stress ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1573-5028
    Keywords: promoter ; electroporation ; protoplasts ; transient assay ; Agrobacterium ; Ti plasmid ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regulatory elements controlling transcriptional activity of the mannopine synthase 2′ promoter (mas 2′) were defined by analysis of deletion mutants in transient expression assays in maize protoplasts. Deletion of the region between −305 and −290 containing sequence similarity to the octopine synthase (ocs) promoter element reduced activity by 67% compared to wild type activity. Less than 1% of the activity remained in 5′ deletions downstream of −153. Inclusion of various heterologous enhancer-like sequences immediately upstream of position −325 increased activity by up to 7.5-fold. Insertion of the −325 to −275 sequence alone, or in combination with heterologous enhancer-like elements, restored activity of some of the 5′-deletion mutants. Restoration of activity was not obtained with mutants deleted past position −127. Our results suggest that a single class of nuclear proteins from maize interact with high affinity at elements designated mas b (−306 to −275; mas 1′ element), d (−127 to −108), and e (−82 to −39; mas 2′ element) as well as the 20 bp element from the ocs promoter. Although the binding site at mas d only appears to accommodate a single protein, this element has the potential to make a weak, but positive, contribution to the activity of the mas 2′ promoter. The binding of nuclear proteins could not be demonstrated at mas a and c, both of which showed limited homology to the ocs element. Mutational evidence suggested that mas a and c may also contribute to mas 2′ transcription.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1573-5028
    Keywords: ribosomal protein ; rps12 ; rpl20 ; clpP ; chloroplast genome ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    ISSN: 1573-5028
    Keywords: cycloheximide ; leaf ; nitrate induction ; nitrate reductase transcript ; root ; scutellum ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nitrate induction of NADH:nitrate reductase mRNA in maize roots, scutella and leaves was investigated in the presence and absence of inhibitors of protein synthesis. In the absence of inhibitors, nitrate treatment caused a fairly rapid (2 to 3 h) increase in the level of the nitrate reductase transcript in all tissues. When cytoplasmic protein synthesis was inhibited by cycloheximide, nitrate reductase mRNA was induced by nitrate in all tissues to levels equal to or greater than those found with nitrate treatment alone. Treatment of maize tissues with cycloheximide in the absence of nitrate had only a small effect on the accumulation of the nitrate reductase mRNA. Inhibition of organellar protein synthesis with chloramphenicol also had little or no effect on nitrate-induced nitrate reductase mRNA accumuiation in roots and scutella, but did appear to partially inhibit appearance of transcript in leaves. Excision of scutella in the absence of nitrate was sufficient to cause some accumulation of the nitrate reductase transcript. Since cytoplasmic protein synthesis was not required for expression of nitrate reductase transcripts, induction of these transcripts by nitrate is a primary response of maize to this environmental signal. Thus, it appears that the signal transduction system mediating this response is constitutively expressed in roots, scutella and leaves of maize.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; ATPase ; cpn60 ; developmental regulation ; molecular chaperones ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mitochondria contain a nuclear-encoded heat shock protein, HSP60, which functions as a chaperonin in the post-translational assembly of multimeric proteins encoded by both nuclear and mitochondrial genes. We have isolated and sequenced full-length complementary DNAs coding for this mitochondrial chaperonin in Arabidopsis thaliana and Zea mays. Southern-blot analysis indicates the presence of a single hsp60 gene in the genome of A. thaliana. There is a high degree of homology at the predicted amino acid levels (43 to 60%) between plant HSP60s and their homologues in prokaryotes and other eukaryotes which indicates that these proteins must have similar evolutionarily conserved functions in all organisms. Northern- and western-blot analyses indicate that the expression of the hsp60 gene is developmentally regulated during seed germination. It is also heat-inducible. Developmental regulation of the (β-subunit) of F1-ATPase, an enzyme complex that is involved in the cyanide-sensitive mitochondrial electron transport system, indicates that imbibed embryos undergo rapid mitochondrial biogenesis through the early stages of germination. Based on the functional role of HSP60 in macromolecular assembly, these data collectively suggest that the presence of higher levels of HSP60 is necessary during active mitochondrial biogenesis, when the need for this protein is greatest in assisting the rapid assembly of the oligomeric protein structures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    ISSN: 1573-5028
    Keywords: pollen-specific gene expression ; promoter analysis ; transient assays ; Tradescantia ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have previously reported the isolation and characterization of a gene (Zm 13) from Zea mays which shows a pollen-specific pattern of expression. Stably transformed tobacco plants containing a reporter gene linked to portions of the Zm 13 5′ flanking region show correct temporal and spatial expression of the gene. Here we present a more detailed analysis of the 5′ regions responsible for expression in pollen by utilizing a transient expression system. Constructs containing the β-glucuronidase (GUS) gene under the control of various sized fragments of the Zm13 5′ flanking region were introduced into Tradescantia and Zea mays pollen via high-velocity microprojectile bombardment, and monitored both visually and with a fluorescence assay. The results suggest that sequences necessary for expression in pollen are present in a region from −100 to −54, while other sequences which amplify that expression reside between −260 and −100. The replacement of the normal terminator with a portion of the Zm13 3′ region containing the putative polyadenylation signal and site also increased GUS expression. While the −260 to −100 region contains sequences similar to other protein-binding domains reported for plants, the −100 to −54 region appears to contain no significant homology to other known promoter fragments which direct pollen-specific expression. The microprojectile bombardment of Tradescantia pollen appears to be a good test system for assaying maize and possibly other monocot promoter constructs for pollen expression.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 19 (1992), S. 217-230 
    ISSN: 1573-5028
    Keywords: chlorophyll a/b-binding protein genes ; Glycine ; LHCP II ; photosynthesis ; soybean ; ribulose-1,5-bisphosphate carboxylase genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The levels of chlorophyll a/b-binding protein (Cab) gene polysomal poly(A)+ mRNA were quantitated throughout the development of Glycine max L. Cab mRNAs were abundant in young expanding leaves, representing 6.1% of the leaf mRNA population. Lower Cab mRNA levels were present in embryos, stems, and cotyledons of developing seedlings; the lowest levels were found in roots where they accounted for 0.04% of the polysomal poly(A)+ mRNA of this organ. To determine the contribution of different members of the Cab gene family to the Cab mRNA populations, a quantitative S1 nuclease reconstruction assay was developed. Cab3, Cab4, and Cab5 mRNAs were detected in all stages examined during soybean development but their levels underwent differential changes. Cab3 encodes the most abundant Cab mRNA in young leaves, developing embryos, and in Stage VII cotyledons from the developing soybean seedling. The levels of Cab mRNAs were compared to the levels of ribulose-1,5-bisphosphate carboxylase small subunit gene mRNA and differences in their patterns of accumulation were noted. Collectively these data indicate that during soybean embryogenesis developmental control mechanisms supersede light-regulatory signals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1573-5028
    Keywords: TATA box ; TFIID ; transcription factor ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We isolated a complementary DNA (cDNA) encoding the TATA-binding factor ‘TFIID’ from a wheat seedling cDNA library. The wheat TFIID transcript of 1.2 kb poly(A)+ RNA was expressed at a low level early in germination, but gradually increased as the seedlings developed. In vitro binding experiments showed that the bacterially expressed wheat TFIID protein could specifically bind to the TATA boxes of the cauliflower mosaic virus (CaMV) 35S, wheat histone H3 and adenovirus major late genes with different affinity. A comparison with Arabidopsis TFIID showed the presence of a plant-specific region consisting of 13 amino acids at the divergent amino terminus and a conserved region (182 amino acids) at the carboxy terminus longer than that observed in yeasts (180 amino acids) and animals (181 amino acids).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    ISSN: 1573-5028
    Keywords: rRNA ; PCR ; ITS ; DNA sequence ; nucleotide ; Triticum speltoides ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    ISSN: 1573-5028
    Keywords: rRNA ; PCR ; ITS ; DNA sequence ; nucleotide ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1573-5028
    Keywords: mitochondrial DNA ; repeated sequences ; ribosomal RNA ; t-elements ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report the sequence of a 7.2 kilobase pair DNA fragment containing a copy of the wheat mitochondrial gene (rrn26) that encodes the mitochondrial large-subunit ribosomal RNA (26S rRNA). The mature 26S rRNA was determined by direct RNA sequencing to be 3467 nucleotides long, and to share a 5′-terminal pentanucleotide (5′-AUCAU), thought to be important in post-transcriptional processing, with the wheat mitochondrial small-subunit (18S) rRNA. Two other prominent features of the sequence were noted. First, upstream of rrn26 are located two tandem copies of a 70 base pair element containing a putative mitochondrial promoter motif (TCGTATAAAAA). Second, downstream of rrn26 is a sequence element that, if transcribed, would produce and RNA with a secondary structure resembling that of tRNAs but differing sufficiently from the latter structure to preclude any transcript from functioning normally in translation. These upstream and downstream sequence elements may play a role in the expression of rrn26 in wheat mitochondria.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    ISSN: 1573-5028
    Keywords: chloroplast ; gene expression ; photosystem 2 ; transcription ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The time course of the accumulation of the transcripts from 13 psb genes encoding a major part of the proteins composing photosystem II during light-induced greening of dark-grown wheat seedlings was examined focusing on early stages of plastid development (0.5 h through 72 h). The 13 genes can be divided into three groups. (1) The psbA gene is transcribed as a single transcript of 1.3 kb in the dark-grown seedlings, but its level increases 5- to 7-fold in response to light due to selective increase in RNA stability as well as in transcription activity. (2) The psbE-F-L-J operon, psbM and psbN genes are transcribed as a single transcript of 1.1 kb, two transcripts of 0.5 and 0.7 kb and a single transcript of 0.3 kb, respectively, in the dark-grown seedlings. The levels of accumulation of every transcript remain unchanged or rather decrease during plastid development under illumination. (3) The psbK-I-D-C gene cluster and psbB-H operon exhibit fairly complicated northern hybridization patterns during the greening process. When a psbC or psbD gene probe was used for northern hybridization, five transcripts differing in length were detected in the etioplasts from 5-day old dark-grown seedlings. After 2 h illumination, two new transcripts of different length appeared. Light induction of new transcripts was also observed in the psbB-H operon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 126 (1992), S. 265-275 
    ISSN: 1432-1424
    Keywords: photosynthesis ; thylakoids ; electrochromism ; gramicidin ; conductance ; dimerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effect of the pore-forming antibiotic gramicidin on pure lipid membranes is well characterized. We studied its action in protein-rich thylakoid membranes that contain less than 25% (wt/wt) acyl lipids. A transmembrane voltage was induced by flashing light, and its decay was measured and interpreted to yield the distribution of gramicidin over thylakoids, its dimerization constant and its single-channel conductance in this membrane. The distribution of gramicidin over the ensemble of thylakoids was immediately homogeneous when the antibiotic was added under stirring, while it became homogeneous only after 20 min in a stirred suspension that was initially heterogeneous. The dimerization constant, 5×1014 cm2/mol, was about 10 times larger than in pure lipid membranes. This was attributed to the upconcentration of gramicidin in the small fractional area of protein free lipid bilayer and further by a preference of gramicidin for stacked portions of the membrane. The latter bears important consequences with regard to bioenergetic studies with this ionophore. As gramicidin was largely dimerized from a concentration of 1 nm (in the suspension) on, the membrane's conductance then increased linearly as a function of added gramicidin. When the negative surface potential at the thylakoid membrane was screened, the conductance of a single gramicidin dimer agreed well with figures reported for bilayers from neutral lipid (about 0.5 pS at 10 mm NaCl). The modulation of the conductance by the surface potential in spinach versus pea thylakoids and between different preparations is discussed in detail.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 84 (1992), S. 798-802 
    ISSN: 1432-2242
    Keywords: Zea mays ; C-banding ; Cell size ; Chloroplast number ; Cold tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary C-band number, guard cell length, and chloroplast number per guard cell were determined for eight maize populations. These populations consisted of maize selected for cold tolerance at the University of Nebraska as well as the original unselected populations. The genome size of these populations had previously been determined. C-band number fluctuated concertedly with the changes in genome size indicating that deletions and additions of constitutive heterochromatin occurred during selection, resulting in altered genome sizes. Guard cell size of all the cold tolerant populations was greater than the cell size of the respective nonselected populations. Chloroplast number per guard cell was also higher in all the cold tolerant populations than in their parental populations, but the increases were not statistically significant. The results indicate that changes in genome size that occurred during selection for cold tolerance are the result of changes in amounts of C-band heterochromatin and that the selection process results in an increase in cell size in the cold tolerant populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 1871-4528
    Keywords: water-stress ; photosynthesis ; yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Relations between measurements of the slow kinetics of chlorophyll fluorescence and growth and yield were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Drought reduced total dry matter production and yields and increased tuber dry matter concentration. Drought increased harvest index in cv. Spunta, but decreased it in cv. Pentland Crown. Total dry matter production was correlated with each of constant fluorescence, variable fluorescence and the half life of the decay in variable fluorescence. These correlations were determined largely by the effect of treatment, and did not discriminate effectively between genotypes within a treatment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 1871-4528
    Keywords: water-stress ; photosynthesis ; leaf water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The slow kinetics of chlorophyll fluorescence were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Constant and variable fluorescence (F o andF v respectively) declined with time in plants from both irrigated and droughted treatments, but the decline was greater in droughted than irrigated plants. However, the yield of variable fluorescence (F v/(F o+F v)) was unaffected by the drought treatment. The main effect of drought was upon the quenching of variable fluorescence. Both the half life of the decay of variable fluorescence (q1/2) and the secondary maximum (M) were significantly greater in the droughted plants than in those from the irrigated treatment. Significant differences between genotypes were found forF v/(F o+F v),M andq 1/2. Genotype-by-treatment interactions were non-significant for all the variables examined. Changes in chlorophyll fluorescence transients were not closely related to changes in leaf water potential.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 169 (1992), S. 49-56 
    ISSN: 1615-6102
    Keywords: Lectin ; Plasma membrane ; Protoplast isolation ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An improved method for the mechanical release of protoplasts from plant tissues is described. The historically-low yield of mechanically-released protoplasts is greatly increased by use of a simple electrically-driven tissue sheer and by optimization of various other steps in the procedure. As counted by light microscopy of a purified preparation, the number of mechanically-released protoplasts obtained is about 6×104 per gram fresh weight of cortical tissue from the primary root of maize (Zea mays L. WF9×Mo 17) seedlings. Nuclear staining of the preparation, however, shows that about half of these protoplasts lack a nucleus and thus are actually subprotoplasts. Comparison of lectin binding to the plasma membranes of mechanically-and enzymatically-released protoplasts shows that both types contain binding sites forRicinus communis agglutinin. Binding sites for peanut (Arachis hypogaea) agglutinin are not naturally present on mechanically-released protoplasts but are generated by exposure to a mixture of Cellulysin and Pectolyase Y-23, the cell wall-degrading enzymes used to prepare enzymatically-released protoplasts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 167 (1992), S. 33-42 
    ISSN: 1615-6102
    Keywords: Daucus carota ; Zea mays ; Vigna radiata ; Helicoidal cell walls ; Polylamellate cell walls ; Rapid-freeze deep-etch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper reports on preliminary investigations into the structure of cell walls of varying complexity as revealed by the rapidfreeze deep-etch technique. Three cell types from different species were examined in order to compare the three-dimensional arrangement of random, polylamellate and helicoidal walls. Each cell type displayed a distinctive level of organisation with respect to the cellulose microfibrils and the matrix material. In polylamellated walls, the microfibrils within each layer were linked to each other by 16–20 nm long side chains regularly spaced along the length of the microfibril. In helicoidal walls, the shifting of the microfibrils could cleary be seen, yet no recognisable structures were observed which could mediate this movement.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 171 (1992), S. 123-133 
    ISSN: 1615-6102
    Keywords: Endosperm ; Floury-2 ; Immunocytochemistry ; Protein bodies ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The seed storage proteins of maize (Zea mays L.) are synthesized during endosperm development on membrane-bound polyribosomes. These proteins, collectively called zeins, are translocated into the lumen of the rough endoplasmic reticulum, where they assemble into protein bodies. Protein body formation in normal genotypes occurs via an ordered deposition of the various types of zeins, and leads to the formation of spherical structures with a diameter of about 1 μm. These structures consist of a central core that contains predominantly α-zein; this central region is surrounded by a peripheral layer of β- and γ-zeins, and the entire structure is bounded by rough endoplasmic reticulum. In the endosperm mutant floury-2 the levels of all classes of zeins are reduced; these kernels exhibit an opaque phenotype instead of the vitreous phenotype observed in normal genotypes. In contrast to the discrete, spherical protein bodies which are formed in normal maize endosperm, the protein bodies within floury-2 endosperm are irregular and the zeins are disorganized; patches of β- and γ-zeins occur within irregularly lobed clusters of α-zein within the lumen of the rough endoplasmic reticulum. The implications of this aberrant distribution are discussed, both with respect to protein body development and kernel characteristics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 1615-6102
    Keywords: Endosperm ; Zea mays ; Immunolocalization ; Rough endoplasmic reticulum ; Binding protein ; Protein bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A maize 75 kDa protein recently has been identified as a plant homolog of the mammalian binding protein (BiP). To better understand the function of BiP in protein body formation in maize endosperm, immunomicroscopy studies were conducted on three maize endosperm mutants, floury-2, Mucronate, and Defective endosperm-B 30, in which the level of BiP is highly elevated. Our results showed that protein body morphology in all three mutants was altered. In addition, BiP was localized in both the ER and peripheral regions of the abnormal protein bodies. The degree to which protein body morphology differed from normal was positively correlated with increased amounts of BiP. In addition, the accumulation of BiP in abnormal protein bodies increased with protein body maturation. In the three endosperm mutants, the arrangement of zeins within protein bodies had been perturbed, yet none of the specific zein subclasses exhibited the staining pattern found for BiP. The association of BiP with abnormal packaging of proteins in protein bodies may reflect a biological function to mediate protein folding and assembly in maize endosperm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1573-5176
    Keywords: adaptation ; β-carotene ; Dunaliella salina ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic characteristics of Dunaliella salina with high (red form) and low β-carotene (green form) concentrations were studied. D. salina growing in brine saltworks exhibited a high level of β-carotene (15 pg cell−1). The rate of oxygen evolution as a function of irradiance was higher in the red than in the green form (on chlorophyll basis). Photosynthetic inhibition of the green form was observed above 500 µmol m−2 s−1. The red form appeared more resistant to high irradiance and no inhibition in O2 evolution was observed up 2000 µmol m−2 s−1. However, when these results are expressed on a cell number basis the rate of oxygen evolution was significantly higher in the green form. Carbonic anhydrase (CA) activity (total, soluble, membrane bound) was found in red and green forms. CA was higher in the red form on a chlorophyll basis, but lower if expressed on a protein basis. The light dependent rate of oxygen evolution and photoinhibition depends on the concentration of β-carotene in D. salina cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied phycology 4 (1992), S. 1-9 
    ISSN: 1573-5176
    Keywords: photobioreactor ; flat plate air-lift reactor ; Chlorella ; Synechococcus ; hydraulic characteristics ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A flat plate, multi-pass air lift reactor (FPALR) for the culture of photosynthetic organisms was constructed from twin wall acrylic sheet and its performance characterised. When operated at an air input of 2.01 min−1 the multi-pass system had a Reynolds number of 5200 indicating fully turbulent flow. Chlorella vulgaris 211/11c was found to have a stationary phase biomass of 1.48 g 1−1 when grown in the flat plate air lift reactor (FPALR) at 100 µmol m−2s−1 compared to 1.11 g 1−1 when cultured in the continually stirred tank reactor (CSTR) at the same PFD (photon flux density). The same organism cultured at 200 µmol m−2s−1 achieved a stationary phase biomass of 1.71 g 1−1 in the FPALR. In contrast, Scenedesmus sp. produced a stationary phase biomass of 2.27 g1−1 and 1.27 g1−1, when cultured at 100 µmol m−2s−1 in the FPALR and the CSTR respectively. The growth rates of both organisms were also higher in the PFALR.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Plant foods for human nutrition 42 (1992), S. 165-173 
    ISSN: 1573-9104
    Keywords: Calcium ; absorption ; wheat ; Bengal gram
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheatchapati, wheat+Bengal gram (80∶20 and 70∶30)chapatis and casein diets, at 10 percent protein level, were fed to rats for 12 weeks to study the effect on calcium utilization. The supplementation of Bengal gram to wheat diets significantly improved the calcium absorption. The urinary calcium excretion in wheat+Bengal gramchapati diets was significantly less than that of wheatchapati diet fed group. The in vivo45Ca absorption (CPM/100 μl serum) was also less in wheatchapati group as compared to wheat+Bengal gramchapati diets fed groups. The supplementation of legumes to cereals improved the calcium utilization and it may be concluded that there will be no risk of occurance of protein induced hypercalciuria.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 234 (1992), S. 353-360 
    ISSN: 1617-4623
    Keywords: Zea mays ; Somatic instability ; Bronze-2 ; Genomic shock ; Pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary After epigenetic loss of Mutator activity, the family of Mu elements in Zea mays becomes immobile and highly methylated; in addition, Mu9, the presumptive autonomous regulatory element, is transcriptionally silent and its copy number decreases in successive crosses to non-Mutator lines. Spontaneous reactivation, scored as restoration of somatic instability of potentially mutable alleles of Bronze-2, of such cryptic Mutator lines is rare, occurring with a frequency of about 10−4. Irradiation of pollen with 254 nm ultraviolet light increases reactivation rate in the progeny kernels by up to 40-fold. Accompanying reactivation, the copy number of Mu9 elements increased, two-fold in one line and 20 to 40-fold in a second line. Reactivation may involve direct DNA damage or immediate physiological stress in the treated pollen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 233 (1992), S. 379-387 
    ISSN: 1617-4623
    Keywords: Bz2 gene ; Transcriptional regulation ; Anthocyanin pathway ; Transient assay ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The putative maize transcription factor genes R and C1 are required for expression of reporter genes with promoters from the Bz1 and A1 genes, which encode enzymes required for anthocyanin biosynthesis in maize. Bz2 is another anthocyanin biosynthetic gene; we show that expression of a reporter gene from the Bz2 promoter also requires R and C1 when the fusion construct is introduced into maize kernels by particle gun bombardment. When electroporated into maize protoplasts from a suspension cell line not synthesizing anthocyanins, reporter genes with Bz2, Bz1, and A1 promoters are expressed only when both R and C1 expression plasmids are co-electroporated. Electroporation of R and C1 expression plasmids also induces the endogenous genes required for anthocyanin synthesis, resulting in pink protoplasts within 24 h. RNase protection analysis demonstrates that accumulation of mRNA from the endogenous Bzl and Bz2 genes absolutely requires introduced R and C1. In time-course experiments there is a delay of 3–6 h before the Bz2 promoter is activated, supporting the proposed role for R- and C1-encoded proteins in transcriptional control. An excess of R relative to C1 suppresses expression of A1, Bz1, and Bz2 promoters, suggesting an interaction between the R and C1 proteins.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 233 (1992), S. 388-394 
    ISSN: 1617-4623
    Keywords: Viral vector ; Transposable element ; Zea mays ; Agroinfection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have previously shown that the maize transposable element Ds1 introduced into maize plants by agroinfection can be excised from the genome of geminivirus maize streak virus (MSV). Excision depended strictly on the presence of an active Ac element in the plants. In this study, the excision products or “footprints” left in the MSV genome after Ds1 excision were extensively characterized and the effects of flanking sequences on Ds1 excision were analysed. Most types of footprints obtained were comparable to those described for Ds1 excision in the maize genome, and could be explained by the models proposed for excision of plant transposable elements. In two revertants, however, some terminal sequences of the Ds1 element were found to have been left behind at the excision site. The finding of this novel type of Ds1 footprint indicated that gene conversion events occurred during and/or after Ds1 excision from the MSV genome. A partial deletion of one copy of the 8 by duplications flanking the Ds1 element had no effect on the frequency or on the types of footprints of Ds1 excision from the MSV genome. Thus, the duplicated 8 by sequences flanking the transposable element are not involved in Ds1 excision. These results, as well as a statistical analysis of the modifications of the bases flanking the Ds1 element after excision, are discussed in terms of excision models.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 231 (1992), S. 369-374 
    ISSN: 1617-4623
    Keywords: Zea mays ; Transcription ; Transformation ; Endosperm ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 43 by fragment containing the — 300 region upstream control element common to the endosperm expressed zein genes of Zea mays L. has been analyzed by in vivo and in vitro techniques. Transient transformation studies with protoplasts from a maize endosperm culture indicate that the element positively affects CaMV 35S promoter-driven gene expression, and that this effect is both orientation- and position-dependent. Band-shift and Southwestern blotting experiments demonstrate that the element is specifically bound by different sets of DNA-binding proteins from seedling and endosperm nuclei. A 2 by substitution within the most conserved region of the element both reduces the stimulatory effect on transcription and alters the binding of nuclear proteins from both tissues.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 233 (1992), S. 269-277 
    ISSN: 1617-4623
    Keywords: Zea mays ; Bz2 locus ; Natural antisense transcripts ; Transposable elements ; Gene family
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of the transcription pattern of theBz2 locus revealed that overlapping transcripts are derived from opposite DNA strands. The most abundant transcript (sense transcript) has an open reading frame coding for a protein of 241 amino acids, whilst in the antisense orientation no open reading frame has been detected; the antisense transcripts are detected only in those tissues that show high levels of sense transcript. Particle gun experiments indicate that the sense transcript is sufficient to provide theBz2 function. The promoter driving the sense transcript contains the elements usually found in front of eukaryotic genes. In addition an element with similarity to theC1 andR binding sites identified in theBz1 promoter is found. Further upstream in the promoter region a transposon-like insertion has been identified. This element has features similar to members of theAc/Ds transposable element family. The putativeBz2 protein shows similarity to various other plant proteins and to anEscherichia coli protein. All related proteins have in common the fact that they are involved in stress responses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 140 (1992), S. 311-314 
    ISSN: 1573-5036
    Keywords: boron toxicity ; diagnosis ; foliar analysis ; mineral nutrition ; nutrient leaching ; rain ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of rain on foliage elemental composition, especially B, was assessed using samples of wheat collected at three harvests from a field trial conducted in soil containing excessive levels of B. Moderate rainfall substantially decreased both the B concentration and content of whole shoots and young leaves. The change in B concentration due to rain suggests that foliar analysis is unreliable for diagnosing B toxicity. For the other elements examined (Ca, Cu, Mg, Mn, Mg, P, S, Zn), rainfall had little effect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 142 (1992), S. 281-285 
    ISSN: 1573-5036
    Keywords: barley ; mixed-cropping ; peas ; root activity ; rooting-depth ; tracers ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Lithium was used as a non-radioactive tracer to investigate the root activity of two cereals (wheat and barley), and of two contrasting cultivars of pea (leafy and semi-leafless), both in pure stands and in mixtures. The mixtures included combinations of each cereal with each pea cultivar in single rows, alternative rows and cross-drilled. Total lithium uptake (mg m-2) was higher for wheat than for barley, and higher for semi-leafless pea than for leafy peas. Growing cereals with peas reduced the total lithium uptake by peas, compared with pure stands, especially in alternate-row mixtures. Growing peas with cereals only reduced the total Li uptake by cereals when they were cross-drilled. The Li uptake by wheat, barley and peas generally decreased with soil depth in a similar manner; however, semi-leafless peas absorbed proportionately more Li from close to the soil surface than did leafy peas. Both pea cultivars absorbed more Li at 10–20 cm depth when grown in intimate mixtures with cereals, compared with less intimate mixtures or pure stands. The potential of lithium as a non-radioactive tracer in mixed-cropping studies is briefly discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 144 (1992), S. 199-205 
    ISSN: 1573-5036
    Keywords: acid phosphatase ; ectoenzymes ; naphthyl phosphate ; Picea abies ; rhizosphere ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract For in vivo demonstration of acid phosphatase activity in the rhizosphere of soil-grown plants filter papers were treated with a mixture of 1-naphthyl phosphate as substrate and the diazonium salt Fast Red TR as an indicator. After enzymatic hydrolysis, 1-naphthol forms a red complex with Fast Red TR. This method was applied to 8-day old maize plants and 3-year old Norway spruce plants growing in rhizoboxes in soil under non-sterile conditions. The treated filter paper is placed at the surface of roots and soil and acid phosphatase activity is visualized as a red-coloured ‘root print’ on the filter paper. The method can be used as a qualitative analysis of acid phosphatase in the rhizosphere. It also allows a rough estimate of phosphatase activity in different root zones.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    ISSN: 1573-5036
    Keywords: aluminium ; aluminium tolerance ; calcium ; magnesium ; Triticum aestivum L. ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The activities of inorganic, monomeric aluminium (Al) species in the root environment are important in the toxicity of Al to plant roots, which may be ameliorated by increased activities of basic cations. Additionally, it has been suggested that electro-chemical processes in walls of root cells play a role in Al tolerance. Empirical models were proposed to accomodate genetic and calcium (Ca) and magnesium (Mg) ameliorative effects on Al toxicity. The models were tested using data from a solution culture study (with ionic strength 1.6 to 8.6 mM) in which wheat (Triticum aestivum L.) cvv. Warigal (Al-sensitive) and Waalt (Al-tolerant) were grown for 28 d at 0, 10 and 20 μM Al, in factorial combination with 200, 400, 800 and 1600 μM Ca and 100, 200, 400 and 800 μM Mg. There was a poor relationship between relative total dry mass (TDM) (calculated as a percentage of the average TDM of each cultivar in the absence of added Al) and the activity of Al3+ or the sum of the activities of the monomeric Al species in solution. A model based on the ratios of activities of cations in solution, taking valency into consideration, was more successful, accounting for ca 85% of the observed variation in relative TDM. There were no systematic variations between observed values and those estimated by the model.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    ISSN: 1573-5036
    Keywords: ammonium ; cyanides ; Gaeumannomyces graminis var tritici ; nitrate ; nitrogen fertilizer ; pseudomonads ; soil conduciveness ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a field cropped with wheat, a high and low level of soil conduciveness to take-all were induced by applying a nitrogen fertilizer with either calcium nitrate or ammonium sulphate. From these two soils, two representative populations of fluorescent pseudomonads were tested for their in situ behaviour. Take-all index and root dry weight were assessed on plants cropped in soils infested with Gaeumannomyces graminis var tritici (Ggt) and each bacterized with one of the isolates of fluorescent pseudomonads. The bacteria tested can be split into three groups: antagonists which reduce take-all, deleterious isolates which aggravate the disease and neutral without evident effect on the disease. The predominance of antagonistic fluorescent pseudomonads in the NH4-treated soil and the predominance of deleterious ones in the NO3-treated soil was confirmed after statistical analysis. The microbial impact on take-all must be more considered as the resulting effect of divergent activities of both rhizobacteria types than the only consequences of the presence of antagonistic pseudomonads. All the high cyanogenic pseudomonads were antagonists in situ and were more numerous in the NH4-treated soil than in the NO3-treated soil.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    ISSN: 1573-5036
    Keywords: ammonium ; Gaeumannomyces graminis var tritici ; nitrate ; nitrogen fertilizers ; fluorescent pseudomonads ; root system ; soil conduciveness ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Take-all of wheat, caused by Gaeumannomyces graminis var tritici (Ggt), is reduced by ammoniacal fertilizers as compared to nitrate sources. This influence of nitrogen on the disease is only observed on nodal roots at flowering. But soil conduciveness to take-all, as measured in a soil bioassay, is modified earlier. Forty days after nitrogen application at early tillering, the NH4-treated soil became less conducive than the NO3-treated one. When nitrogen applications are done at sowing and at tillering, differences in disease propagation between the two soils are enhanced. Results from four years of experimentation show that when the level of natural soil inoculum is high, disease severity is reduced by ammonium, showing an effect on the parasitic phase of Ggt. At a low level of natural inoculum the effect of the source of nitrogen is mainly observed on the percent of infected plants, indicating that the saprophytic and preparasitic phases are affected. Rhizospheric bacterial populations increase from sowing to tillering, but differences on take-all conduciveness after tillering are not correlated with differences in the amounts of aerobic bacteria or fluorescent pseudomonads isolated from soils treated with different sources of nitrogen. Qualitative changes in fluorescent Pseudomonas spp. populations, like in vitro antagonism, are more likely to explain differences in soil conduciveness to take-all than are quantitative changes in this group. Nevertheless, the introduction of Ggt in a cropped soil leads to a greater increase in fluorescent pseudomonads populations than in total aerobic bacteria. The delay between reducing soil conduciveness and reducing disease in the field with ammonium nitrogen fertilization, the qualitative change of fluorescent pseudomonads populations and the role of necroses in rhizobacteria multiplication, provide information leading to our representation of a dynamic model based on the differentiation of the wheat root system into seminal and nodal roots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 146 (1992), S. 163-168 
    ISSN: 1573-5036
    Keywords: genetic variability ; NIR ; ploidy ; phosphorus ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract More efficient utilization of phosphorus by wheat plants is needed to extend the useful life of the phosphate reserves in the world, to reduce the cost of producing crops, and to improve the value of the grain and the straw produced. In this paper definitions of efficient use of phosphorus by wheat are reviewed, genotypic variation in phosphorus efficiency is reported, some consequences of breeding for greater efficiency are discussed, and ways to select more efficient genotypes are suggested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 60 (1992), S. 89-95 
    ISSN: 1573-5060
    Keywords: cuckoo effect ; gametocidal chromosome/gene ; preferential transmission ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A translocated chromosome segment, derived from Thinopyrum distichum, carries the leaf rust resistance allele Lr19d and a segregation distorter allele, Sd-1d. In translocation heterozygotes, male and female gametophytes lacking the translocation are aborted, the severity of the effect depending on the genotype of the hybrid. The selective abortion of the gametophytes with a normal chromosome 7D appears to be based on the absence of the translocated chromosome rather than the presence of the normal chromosome. The magnitude of the gametocidal response, elicited by Sd-1d, is under multigenic control. A number of chromosomes, the individual effects of which are generally small, may act to suppress or promote the response. Chromosome arms 2AL, 2BL, 5BL and 5DL of ‘Chinese Spring’ were found to reduce sensitivity to the presence of the gametocidal chromosome. Chromosome 3B of ‘Inia 66-1’ also reduce the gametocidal response while chromosome arm 6DS of ‘Chinese Spring’ may promote the effect
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; stress tolerance ; genetic variance ; genetic correlation ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Wheat (Triticum aestivum L.) cultivars grown in the southern Great Plains of the U.S.A. are exposed to a wide range of moisture conditions due to large fluctuations in the amount and frequency of rainfall. Yield stability under those conditions is therefore a desirable trait for wheat breeders. Our primary objective was to quantify various genetic parameters for grain production in drought-stressed and irrigated environments. We also attempted to predict and measure yield responses when selection is practiced in either drought-stressed or irrigated environments, or both. Seventy F2-derived lines from the cross, TAM W-101/Sturdy, were evaluated at Goodwell, OK, under irrigated and naturally drought-stressed conditions in 1987 and 1988. Genetic variance and heritability estimates were higher in the irrigated environment than in the drought-stressed environment. The genetic correlation coefficient for yields in the two environments was 0.20±0.16, indicating that selection of widely adapted genotypes requires testing in both environments. Based on the genetic variance/covariance structure of this particular population, the linear index which maximized the combined expected gain in both environments was 0.66Y1 + 0.34Y2, in which Y1 and Y2 are yields in the irrigated and drought-stressed environments. This index is not expected to apply across all populations; rather, it further supports the hypothesis that testing in either environment alone (drought stressed or irrigated) may not be most effective for increasing either mean productivity or yield under drought stress.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 62 (1992), S. 111-117 
    ISSN: 1573-5060
    Keywords: aluminium ; root growth ; screening ; tolerance ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Aluminium tolerance of 83 genotypes from Croatian and Yugoslav Triticum aestivum germplasm was evaluated in nutrient solutions having Al3+ activities of 0, 12.5 and 25 μM. Relative root length (25 μM Al3+/0 Al) of various genotypes ranged from 2 to 97% (from very sensitive to tolerant to Al). No genotype with Al tolerance close to that of very tolerant cultivar Atlas-66 was found. Soil, climatic, fertilization, and liming effects that wheat plants giving seeds for the nutrient solution Al-tolerance screening had been subjected to during their growth cycle did not influence the Al-tolerance ranking. Significant correlation was found between screening wheat for Al tolerance in nutrient solutions and in acid Pseudogley soil amended with five rates of limestone in a greenhouse experiment. Seed protein concentration was significantly related to the Al-tolerance ranking (r2 = 0.962). Such a significant correlation was not obtained in a case of rheological and other quality characteristics of seeds. Al-tolerant wheat genotypes identified in this study will be used in breeding for improved Al tolerance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1573-5060
    Keywords: heading time ; narrow-sense earliness ; photoperiodic response ; Triticum aestivum ; vernalization requirement ; winter hardiness ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary For breeding early heading wheat cultivars with resistance to frost damage which are well adapted to dry areas of West Asia and North Africa, the relationships between winter hardiness, ear primordia development and heading traits, i.e. veernalization requirement, photoperiodic response and narrow-sense earliness, were assessed using a total of 30 genotypes of wheat (Triticum aestivum L.) grown in an experiment in Syria. The results of artificial freezing tests indicated that cultivars with good winter hardiness were to be found only in the winter wheat cultivars which required 50 or more days of vernalization treatment. These winter wheat cultivars did not initiate internode elongation without vernalization even at 95 days after planting. Thus their ear primordia were still underground and were protected from frost injury at this stage. Photoperiodic response and narrow-sense earliness were not associated with winter hardiness and earliness of internode elongation, but were related to the number of days to heading after planting. This indicated the possibility for breeding early heading cultivars with winter hardiness and tiller frost avoidance by combining high vernalization requirement, short narrow-sense earliness and neutral response to photoperiod.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 63 (1992), S. 3-22 
    ISSN: 1573-5060
    Keywords: wheat ; Triticum aestivum ; yellow (stripe) rust ; Puccinia striiformis ; septoria ; Septoria tritici ; S. nodorum ; eyespot ; Pseudocercosporella herpotrichoides ; resistance genetics ; pathogen variation ; durable resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This introductory chapter contains some general comments about plant breeding and breeding for disease resistance. The use of disease resistant crop plants is an environmentally favourable method of controlling disease but the process of breeding for disease resistance is subject to several constraints. Among them is the variability of pathogens in relation to host resistance. Some parts of this variation can be resolved into gene-for-gene interactions, but the boundaries within which such interactions can be detected are not sharp. The discussion of this variation is illustrated by reference to some important diseases of wheat, especially yellow rust, septoria and eyespot. The objective of obtaining durable resistance is discussed and some contributions of new genetical and molecular techniques to breeding for resistance are considered. It is suggested that new technology will enhance breeding for disease resistance but that established techniques of plant breeding will remain relevant and important.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    ISSN: 1573-5060
    Keywords: cold tolerance ; correlated responses ; germination ; kernel type ; kernel weight ; recurrent selection ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Four cycles of divergent full-sib recurrent selection for the ability to germinate at low temperature were conducted in a maize (Zea mays L.) F2 population. The selection criterion was the high (H) or the low (L) value in algebraic terms of the difference (DG) between germination percentage at 9.5°C (G9.5) detected 19 days after sowing and germination percentage at 25°C (G 25) seven days after sowing; both traits were evaluated in a controlled environment (germinator). Direct and correlated responses estimated during the course of selection were in accordance with those evaluated at the end. Selection for H led to populations with higher DG values, while the reverse was noted for L; differences between H and L populations increased in successive selection cycles, though divergence tended to level off. Selection for H also resulted in higher G 9.5 (day 19), shorter germination time and more flinty kernels, while selection for L led to responses in the opposite direction as well as to a lower G 9.5 detected 37 days after sowing (i.e. at the end of germination). In contrast, responses were negligible for G 25 and varied erratically from one cycle to another for kernel weight.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1573-5079
    Keywords: carotenoid ; chlorophyll fluorescence ; non-photochemical quenching ; pH ; photosynthesis ; zeaxanthin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pH dependence of maximum chlorophyll fluorescence yield (Fm) was examined in spinach thylakoids in the presence of nigericin to dissipate the transthylakoid pH gradient. 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea (DCMU) was present to eliminate photochemical quenching. Thylakoids were prepared from dark adapted leaves (‘dark’ thylakoids) or preilluminated leaves (‘light’ thylakoids). In the latter there had been approximately 50% conversion of the xanthophyll violaxanthin to zeaxanthin, while no conversion had occurred in the former. In the presence of a reductant such as ascorbate, antimycin A sensitive quenching was observed (half maximal quenching at 5 μM), whose pH dependence differed between the two types of thylakoid. Preillumination of leaves resulted in more quenching at pH values where very little quenching was observed in ‘dark’ thylakoids (pH 5–7.6). This was similar to activation of high-energy-state quenching (qE) observed previously (Rees D, Young A, Noctor G, Britton G and Horton P (1989) FEBS Lett 256: 85–90). Thylakoids isolated from preilluminated DTT treated leaves, that contained no zeaxanthin, behaved like dark thylakoids. A second form of quenching was observed in the presence of ferricyanide, that could be reversed by the addition of ascorbate. This was not antimycin A sensitive and showed the same pH dependence in both types of thylakoid. The former type of quenching, but not the latter, showed similar low temperature fluorescence emission spectra to qE, and was considered to occur by the same mechanism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 33 (1992), S. 163-170 
    ISSN: 1573-5079
    Keywords: biosynthetic pathway ; evolution ; free energy ; photochemistry ; photosynthesis ; porphyrin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Living matter is an organized system which requires a continual flux of energy for its survival. As a working assumption, the flux of energy required for the origin of a self-duplicating cell is taken as the power required for the maintenance of a modern cell: 10 mW per g of carbon or some 105 times the output per gram of the sun. Solar photochemistry supplies the energy for the continuing evolution of life and, by continuity, for its origin. The iron oxide-sulfide photosynthetic unit proposed by S. Granick 35 years ago was meant to supply this energy. The evolution of complex organic photosensitizers is rationalized by the Granick hypothesis that biosynthetic pathways recapitulate their evolution. These concepts are discussed in the context of the evolution of photosynthetic systems and the known properties of these pigments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 32 (1992), S. 139-146 
    ISSN: 1573-5079
    Keywords: leaf senescence ; mesophyll conductance ; Oryza sativa L. ; photosynthesis ; specific leaf weight ; stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The grain yield of rice (Oryza sativa L.), as well as of other cereal crops, is limited to a large extent, by the supply of photosynthates produced during grain filling period. In this study, flag leaf photosynthesis (LPS) after heading was compared among 32 cultivars bred during the past century in Japan, to determine if the improvement of LPS has occurred with the breeding advance of high yielding cultivars. Measurement of LPS was made for 5 consecutive years in the paddy field, on the flag leaf of the main stem, at heading (LPS-0), and 2 weeks (LPS-2) and 4 weeks (LPS-4) after heading. LPS decreased with advance of leaf senescence from LPS-0 to LPS-2, and then to LPS-4. However, if nitrogen was top-dressed at the heading time, high LPS-2 was maintained, particularly in the newer cultivars. A significant positive correlation between LPS and the released year of cultivar was found at LPS-2, especially in the nitrogen top-dressed plot, but not at LPS-0 or LPS-4. Cultivar difference in LPS of the senescing leaves were not stable through the different years, whereas LPS-0 was stable over years, suggesting that the LPS in the senescent leaf is susceptible to the environmental variation due to the effects on leaf senescence. Cultivar difference in LPS at any stage was closely associated with mesophyll conductance to CO2, and stomatal conductance was also associated with cultivar difference in such a high LPS as LPS-0 and nitrogen top-dressed LPS-2. Significant correlation between LPS and specific leaf weight was not observed at any stage of the flag leaf.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; Dunaliella ; photosynthesis ; quantum efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The yield of photosynthetic O2 evolution was measured in cultures of Dunaliella C9AA over a range of light intensities, and a range of low temperatures at constant light intensity. Changes in the rate of charge separation at Photosystem I (PS I) and Photosystem II (PS II) were estimated by the parameters ΦPS I and ΦPS II . ΦPS I is calculated on the basis of the proportion of centres in the correct redox state for charge separation to occur, as measured spectrophotometrically. ΦPS II is calculated using chlorophyll fluorescence to estimate the proportion of centres in the correct redox state, and also to estimate limitations in excitation delivery to reaction centres. With both increasing light intensity and decreasing temperature it was found that O2 evolution decreased more than predicted by either ΦPS I or ΦPS II. The results are interpreted as evidence of non-assimilatory electron flow; either linear whole chain, or cyclic around each photosystem.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    ISSN: 1573-5036
    Keywords: Alternaria alternata ; black point ; fertilization ; irrigation ; nitrogen ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Agronomic studies were conducted to examine the effect of fertilizer N on black point incidence in Fielder soft white spring wheat (Triticum aestivum L. em Thell.). Black point incidence rose with increases in the amount of N supplied either as fertilizer applied during the growing season in irrigation water or as soil N, specifically nitrate, from fertilizer N application in previous years. A comparison of four different irrigation regimes demonstrated that black point incidence was highest under frequent irrigation (irrigate to field capacity at 75% available moisture) and lowest under conventional irrigation (irrigate to field capacity at 50% available soil moisture). In each irrigation regime, disease incidence increased as N rates were raised from 0 to 120 kg ha-1. A residual fertilizer-N study demonstrated in 1985 and 1986 that black point incidence generally rose with increasing levels of nitrogen from either preplant applications in the spring or soil nitrate from the previous year. However, additions of fertilizer N were shown to slightly reduce black point incidence at soil nitrate levels above 150 kg ha-1. A two-year fertilizer N study demonstrated that in treatments receiving the same amount (90 kg ha-1) of fertilizer N, the amount broadcast as a preplant treatment versus the amount applied in irrigation water in a fertigation treatment had no effect on black point incidence, but all fertilized treatments had significantly higher levels of disease than the unfertilized check.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 146 (1992), S. 55-59 
    ISSN: 1573-5036
    Keywords: acid soils ; low pH ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Shoot length (cm), shoot fresh weight (g/pot), root length (cm), and root fresh weight (g/pot) were measured on six cultivars of wheat (Triticum aestivum L. cv Saluda, C9733, Gore, Stacy, FL301, and FL302) grown at pH 6.0, 5.5, 5.0, 4.5, or 4.0 for 14 days in ‘white quartz flintshot’ sand. Plants were watered on alternate days with pH-adjusted buffer solutions. All measured plant parameters decreased as H+ concentration increased from pH 6.0 to 4.0. Decreased lengths of shoots and roots were similar among the cultivars as the pH decreased. This indicated a uniform response of wheat cultivars to excess H+ concentration in the soil solution; however, the decrease in shoot and root length was only about 50% as large as was previously reported for sorghum [Sorghum bicolor (L.) Moench.].
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1573-5036
    Keywords: aluminium ; genetics ; inheritance ; toxicity ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of Al on the growth of plants derived from the F3 generation of a cross between Al tolerant (Waalt) and Al sensitive (Warigal) wheat cultivars, grown in low ionic strength nutrient solutions, were assessed by a number of methods viz; root length and haematoxylin stain after 3 days exposure to Al and plant top and root yields, and root length and visual assessment for Al damage after 4 weeks growth. Of these methods haematoxylin stain (3 days) and visual assessment at 4 weeks identified the same plants as being sensitive or tolerant to Al and clearly segregated the 2 populations. Consequently these 2 methods were used as ‘standard’ techniques to determine the ability of the other methods to distinguish between tolerant and sensitive plants. The ratio of plant top: root yields clearly segregated the 2 populations. The 2 populations could not be clearly distinguished based on plant top or root yields, or on root length either after 3 days or 4 weeks exposure to Al. Within the population of tolerant plants, root length was significantly correlated with root weight (r2=0.86) and top weight (r2=0.71). None of these relationships were significant for the population of sensitive plants. These techniques were applied in a number of separate experiments on the F2 and F3 populations from a Waalt × Warigal cross. The results indicate that Al tolerance in wheat is inherited by a single gene and that this gene has incomplete dominance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    ISSN: 1573-5036
    Keywords: aluminium ; electron microscope ; light microscope ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Root tips from aluminium (Al) tolerant (Waalt) and Al sensitive (Warigal) wheat (Triticum aestivum (L). Thell.) cultivars exposed to low concentrations of Al (10 μM) for 10, 24 and 72 hours were examined under the light and electron microscope. After fixing and embedding, longitudinal and transverse thin and ultrathin sections were cut. There was no evidence of Al damage to the root tips of the Al tolerant cultivar under both the light and electron microscope. For the Al sensitive cultivar, Al had no observable effect on the root tips 10 hours after Al addition when examined under the light microscope. When examined under an electron microscope, electron dense globular deposits were observed between the cell wall and cell membrane of the epidermal cells. There was not obvious damage to the cell cytoplasm. Two or 3 days after Al addition, light microscopy showed that the cells in the root tips had become swollen and extensively vacuolated. The tissues appeared disorganised and degenerate, particularly in the epidermis and outer cortical cells. The electron microscope also revealed a thickening of the cell wall. The cell wall was broken down, particularly in the epidermis in the region 4–6 mm from the root tip. The tissue in the meristematic area was largely intact.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 146 (1992), S. 89-98 
    ISSN: 1573-5036
    Keywords: barley ; drought ; halophytes ; productivity ; salinity ; salt tolerance ; sunflower ; water-use efficiency ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The productivity of wheat and barley was compared in soils of different salt concentrations with a limited water supply. Productivity was assessed as total dry weight or dry weight per unit of water used (water use efficiency, WUE). Barley achieved the highest productivity because it used more of the available water and it had a greater WUE for above-ground dry weight. However, when WUE for total organic weight of roots and shoots was determined, or WUE was corrected for grain production, wheat and barley had the same productivity. In two experiments in drying soils with different salt concentrations but the same amount of soil water, wheat and barley had a higher dry weight than salt-tolerant grasses and they were more productive than C4 halophytes and non-halophytes when adjusted for water use. In one experiment, sown at a low plant density, barley and wheat used less water than some halophytes and they completed their life cycle leaving some water behind in the soil. Their higher WUE did not compensate for their lower water use. However, when all species were sown at a high density, wheat and barley were either as productive or more productive than the most salt-tolerant species, including a C4 halophyte, as they used all the available water and had the highest WUE. A sunflower cultivar was similary more productive than a salt-tolerant relative. The contribution that salt-tolerant relatives of wheat, barley and sunflower can make to genetically improving the productivity of these species in dry saline soils is questioned.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 1573-5036
    Keywords: boron ; genetic variation ; major genes ; uptake ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Physiological and genetic studies have been undertaken to further the understanding of genetic variation in response to high concentrations of B in the soil and so facilitate the breeding of tolerant varieties for cultivation in high B regions. Genetic variation in response to high concentrations of B has been identified for a number of crop and pasture species of southern Australia, including wheat, barley, oats, field peas and annual pasture medics. The wheat variety Halberd, which was the most widely grown variety in Australia during the 1970s and early 1980s, is the most tolerant of the current Australian wheat varieties. The mechanism of tolerance for all species studied is reduced accumulation of B by tolerant genotypes in both roots and shoots. Results from experiments of uptake kinetics indicate that control of B uptake is a non-metabolic process. The response of wheat to high B supply is under the control of several major additive genes, one of which has been located to chromosome 4A.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell, tissue and organ culture 28 (1992), S. 129-137 
    ISSN: 1573-5044
    Keywords: cms-T ; in vitro selection ; methomyl resistance ; mitochondrial mutation ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several factors affecting the success of selection in plant populations were examined for their relevance to in vitro selection. Three in vitro selection schemes and two growth assessment procedures were evaluated for effectiveness in selecting for a mitochondrial trait in maize: resistance to the insecticidal compound methomyl. Regenerable maize callus was derived from immature embryos of the three-way hybrid P39/IL766A2 x W182BN containing Texas male sterile cytoplasm (cms-T). Either low, gradually increasing, or high selection pressures were used to grow callus over a period of 3–5 months. There was no significant difference in recovery of resistant plants using these 3 methods. Growth of callus on medium containing methomyl was assessed by increase in fresh weight during the final month of selection or by increase in number of callus pieces over the course of selection. These quantitative measures of growth were unreliable indicators for gain in resistance within the callus population. A procedure for recovery of methomyl resistant and male-fertile cms-T plants is suggested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 33 (1992), S. 171-176 
    ISSN: 1573-5079
    Keywords: photosynthesis ; origin of life ; clays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The origin of photosynthesis is speculated to have involved carbon dioxide and self-replicating iron-rich clays. The later evolution of photosynthesis is considered to have undergone four distinct phases: (1) The photoreduction of carbon dioxide by ferrous ion to form oxalate and formate. (2) The entry of sulfur into the evolving clay system which led to the formation of acetyl thioesters. The polymerization of the acetyl thioeters led to the formation of quinones. The formation of Fe2S2 and Fe4S4 cores appeared in this phase. (3) The ability to fix nitrogen characterized the third phase. This led to the formation of pyrrole, flavin, nicotinamide, phycobilins, porphyrins and chlorophyll. (4) Finally, phosphate entered the evolving system. The chromophores evolved from ferrous ion through the quinones, carotenoids, phycobilins to chlorophyll. This evolution of chromophores implies that photosynthesis began in the UV and evolved through the blue, yellow, orange into the red. The electron transport chain evolved from ferrous ion through the Fe2S2 and Fe4S4 cores to the hemes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    ISSN: 1573-5079
    Keywords: Chlamydomonas ; convexity ; chlorophyll a fluorescence ; Photosystem II heterogeneity ; photoinhibition ; photosynthesis ; PS II repair cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of a 60 min exposure to photosynthetic photon flux densities ranging from 300 to 2200 μmol m−2s−1 on the photosynthetic light response curve and on PS II heterogeneity as reflected in chlorophyll a fluorescence were investigated using the unicellular green alga Chlamydomonas reinhardtii. It was established that exposure to high light acts at three different regulatory or inhibitory levels; 1) regulation occurs from 300 to 780 μmol m−2s−1 where total amount of PS II centers and the shape of the light response curve is not significantly changed, 2) a first photoinhibitory range above 780 up to 1600 μmol m−2s−1 where a progressive inhibition of the quantum yield and the rate of bending (convexity) of the light response curve can be related to the loss of QB-reducing centers and 3) a second photoinhibitory range above 1600 μmol m−2s−1 where the rate of light saturated photosynthesis also decreases and convexity reaches zero. This was related to a particularly large decrease in PS IIα centers and a large increase in spill-over in energy to PS I.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 34 (1992), S. 249-262 
    ISSN: 1573-5079
    Keywords: photosynthesis ; light-harvesting chlorophyll-protein complex ; spinach ; maize
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The monomeric chlorophyll-protein complexes, CP 29 and CP 26 seen in the Camm and Green (1980) and Dunahay and Staehelin (1986) green gels do not always migrate in the order of the apparent molecular weight of their apoproteins as determined by denaturing gel electrophoresis. In barley and corn they do, but in spinach they do not. In addition, in some higher plant species these chlorophyll-protein complexes comigrate on green gels causing confusion in the literature. To remedy this situation and circumvent future confusion, we propose that the CP 29 and CP 26 complexes be named according to the relative molecular weight of their apoproteins on denaturing gels. Our proposal is supported by the results obtained from four antibodies used on Western blot samples of whole thylakoids, grana membranes, and PS II preparations from different plants. The higher molecular weight proteins (proposed CP 29's) react strongly to one set of antibodies, and the lower molecular weight proteins (proposed CP 26's) react strongly to a different set. In spinach, CP 26 antibodies react also with CP 29, but the extent of the cross-reactivity depends critically on the gel electrophoresis system used. Accordingly, a lack of antibody reactivity under certain conditions may not indicate two proteins are unrelated, just simply that a particular epitope is no longer accessible following gel electrophoresis with a particular buffer system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 34 (1992), S. 387-395 
    ISSN: 1573-5079
    Keywords: oscillations ; photosynthesis ; regulation ; phosphate ; down-stream
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; cyclic electron transport ; photorespiration ; photosynthesis ; Photosystem II ; proton gradient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlorophyll fluorescence, light scattering, the electrochromic shift P515 and levels of some photosynthetic intermediates were measured in illuminated leaves. Oxygen and CO2 concentrations in the gas phase were varied in order to obtain information on control of Photosystem II activity under conditions such as produced by water stress, when stomatal closure restricts access of CO2 to the photosynthetic apparatus. Light scattering and energy-dependent fluorescence quenching indicated a high level of chloroplast energization under high intensity illumination even when linear electron transport was curtailed in CO2-free air or in 1% oxygen with 35 μll-1 CO2. Calculations of the phosphorylation potential based on measurements of phosphoglycerate, dihydroxyacetone phosphate and NADP revealed ratios of intrathylakoid to extrathylakoid proton concentrations, which were only somewhat higher in air containing 35 μl l-1 CO2 than in CO2-free air or 1% oxygen/35 μl l-1 CO2. Anaerobic conditions prevented appreciable chloroplast energization. Acceptor-limitation of electron flow resulted in a high reduction level of the electron transport chain, which is characterized by decreased oxidation of P700, not only under anaerobic conditions, but also in air, when CO2 was absent, and in 1% oxygen, when the CO2 concentration was reduced to 35 μll-1. Efficient control of electron transport was indicated by the photoaccumulation of P700 + at or close to the CO2 compensation point in air. It is proposed to require the interplay between photorespiratory and photosynthetic electron flows, electron flow to oxygen and cyclic electron flow. The field-indicating electrochromic shift (P515) measured as a rapid absorption decrease on switching the light off followed closely the extent of photoaccumulation of P700 + in the light.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 238 (1992), S. 189-196 
    ISSN: 1573-5117
    Keywords: photosynthesis ; phytoplankton ; time scales ; environmental variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Static P(I) curves relating photosynthesis to the instantaneous light might not be adequate to describe the activity of algal cells in lakes or oceans where mixing can cause a complex pattern of light variation. In recent years experimental results have provided evidence that, subsequent to changes in light, the rate of photosynthesis may be delayed or exhibit complex temporal dynamics. The model DYPHORA (DYnamic model for the PHOtosynthetic Rate of Algae) takes these dynamics into account by introducing two characteristic response times for the biological processes: (1) the effect of light inhibition having a time scale of minutes to a few hours and (2) the time lag of the rate of photosynthesis for increasing light intensities having a time scale of seconds to minutes. The importance of the dynamic relative to the static description of photosynthesis depends on the time scales of the changes in the environment and the biological response, becoming significant when the time scales are comparable.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 248 (1992), S. 215-234 
    ISSN: 1573-5117
    Keywords: suspended solids ; turbidity ; algae ; photosynthesis ; light ; mining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Placer gold-mining on the West Coast of the South Island of New Zealand provided a field test-bed for investigating the impacts of fine inorganic suspensoids (clays) on streams not subjected to other abuses. The suspensions of clays (40% between 0.55 and 1 µm in diameter) seeping into the streams from gold mines were colloidally stable. The clay particles attenuated light in the streamwater with near maximum efficiency leading to severe degradation of stream optical quality. Turbidity increased from a median of 2.4 NTU upstream often to 〉 100 NTU (median 15 NTU) downstream. The stream waters, which were strongly-coloured by humic substances, were changed from a dark organge colour to a bright ‘muddy’ appearance downstream of mining, and visual clarity was reduced from a few metres to as low as 0.03 m (median 0.33 m). The clay discharges decreased light penetration into the stream water such that irradiance averaged over a 12 hr photoperiod at the bed (typically about 0.3 m depth in runs at baseflow) fell from about 340 µE m−2 s−1 upstream to as low as 80 µE m−2 s−1 (median 190 µE m−2 s−1) at matched downstream sites. This reduction in light proportionally reduced benthic primary productivity downstream of the mining activity. In turn this reduced benthic algal biomass and lowered the phototrophic content of the epilithon. In spite of their extremely low settling velocities (〈 1 µm s−1) some clay particles were deposited on the stream bed owing to entrapment in the epilithon matrix. This decreased the organic content of the epilithon (from an average of 19% upstream to 8.5% downstream) so reducing its quality as food for invertebrate animals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 231 (1992), S. 93-98 
    ISSN: 1573-5117
    Keywords: photosynthesis ; macroalgae ; deep-water ; Bermuda ; Dictyotales
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic performance and dark respiration rates were determined in situ for abundant macroalgae occurring between 27–49 m depths off Bermuda. Brown algae, particularly members of the order Dictyotales, predominated at all deep-water sites, and Stypopodium zonale was the most abundant species. Species showed net photosynthesis at very low ambient irradiances (〈0.01 maximum Io). Lobophora variegata, a species with a highly decumbent growth form, had low productivity across all irradiances. In contrast, Dictyota spp. (D. bartayresii, D. dichotoma, D. divaricata) and S. zonale had high photosynthetic capacity (ca. 400 µmol O2 gdw−1 h−1), and light saturation was not evidenced at the highest ambient irradiance level (300 µE m−1 s−1) for species with thin, flat thalli. Light-harvesting pigment concentrations reflected tissue-nitrogen levels. C:N atom ratios, except for L. variegata and D. divaricata, were within the ratio for balanced growth. The repeated occurrence and photosynthetic efficiency of these Dictyotalean species in subtropical and tropical deep-water habitats emphasize their successful adaptation to low-light, nutrient-poor environments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 238 (1992), S. 1-35 
    ISSN: 1573-5117
    Keywords: periodicity ; diel ; circadian ; clocks ; photosynthesis ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Daily variation in phytoplankton productivity influences the dynamics and linkages between several large scale processes in aquatic ecosystems. As part of an opening address to the 5th International workshop for the Group for Aquatic Productivity (GAP), the daily patterns of variability in photosynthesis for different algal classes was introduced and accompanied by a discussion of the sources of environmental and endogenous regulation of repeating biological oscillations that occur in phytoplankton on timescales of one day. It is suggested that one way to develop a database that serves to sort and predict phytoplankton variability over the day may be to encourage the creation of a ‘temporal library’. Such a library would be comprised of temporally fixed maps of circadian clock-controlled rhythms for individual species, as well as temporally variable maps of diel periodicities that only can be defined for a selected set of environmental conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1573-5117
    Keywords: picoplankton ; photosynthesis ; primary production ; cyprinids ; fish farm pond
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phytoplankton dynamics of a Chinese integrated fish culture pond in the suburbs of Shanghai were studied in September and October 1989. The chlorophyll a concentration was high with a range of 62.5–127.3 µg l−1; however, daily net production of phytoplankton was relatively low, with a range of 0.53–1.94 gC m −2 d−1. Of the total phytoplankton biomass, 70–87% was composed of nanoplankton (〈10 µm) and picoplankton, probably because of the selective feeding by phytoplanktivorous carp. In particular, the chlorophyll a concentration of picoplankton was 2.1 – 14.1 mg m −3, and its contribution to total phytoplankton production rate was high (18–68%).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    ISSN: 1573-5117
    Keywords: photosynthesis ; alpine lake ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic activity by phytoplankton was measured during the ice-free seasons of 1984, 1985 and 1987 using the 14C radioassay in high altitude Emerald Lake (California). Relative quantum yield (αB) and light-saturated chlorophyll-specific carbon uptake (Pm B) were calculated from the relationship of light and photosynthesis fitted to a hyperbolic tangent function. Temporal changes in Pm B showed no regular pattern. Seasonal patterns of αB generally had peaks in the summer and autumn. Phytoplankton biomass (as measured by chlorophyll a) and light-saturated carbon uptake (Pm) had peaks in the summer and autumn which were associated with vertical mixing. Estimates of mean daily carbon production were similar among the three years: 57 mg C m−2 2 d−1 in 1984, 70 mg C m−2 2 d−1 in 1985 and 60 mg C m−2 d−1 in 1987. Primary productivity in Emerald Lake is low compared to other montane lakes of California and similar to high-altitude or high-latitude lakes in other regions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    ISSN: 1573-5117
    Keywords: light/dark cycles ; photosynthesis ; Chlorella ; diurnal variations ; respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlorella pyrenoidosa was grown in three continuous cultures each receiving a different light regime during the light period of a diurnal cycle. Hourly samples taken during the light period were subjected to medium frequency light/dark oscillations of equal duration, ranging from 3 to 240 seconds. The oxygen consumption and production of each sample were measured with an oxygen electrode in a small oxygen chamber. Although the light/dark cycles had little overall influence on photosynthetic activity, the microalgae appeared to adapt to the light regime to which they were subjected. Large differences were found between the maximum chlorophyll-specific production rates (P infmax supB ), the chlorophyll-specific production rates (PB) and the respiration rates between the cultures and treated subsamples. Respiration rates increased during the light period, whilst PB either increased, or had a mid light period minimum or maximum. The culture which received an hourly light oscillation during the light period had the highest P infmax supB and lowest respiration rates, and it is suggested that these algae react as in nature, whereas either a sinusoidal or a block light pattern is ‘unnatural’. The latter light regime is commonly used in laboratory studies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    ISSN: 1573-5117
    Keywords: dynamic light regime ; photosynthesis ; respiration ; quantum requirement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Comparisons were made of photosynthesis in three light limited cyclostat cultures (LD = 8:16, dilution rate 0.7 d−1) of Chlorella pyrenoidosa, differing only in the dynamics of irradiance supply: as a constant rate, i.e. a block culture; as a sine function of the light period, i.e. a sinusoidal culture; as an 8 h sine function superimposed by an 1 h sine function, i.e. an oscillating culture. The sinusoidal culture had a constant minimum quantum requirement for oxygen evolution (QR) of 10.8 over the photoperiod. The OR of the oscillating culture increased from 24 to 37 during the photoperiod. From changes in α and P max we suggest that: (1) photosynthetic units (PSU) of the block and sinusoidal sulture increased in number; (2) increasingly fewer chlorophyll molecules participated in oxygenic photosynthesis with a decreasing turnover time of the PSU's during an oscillating photoperiod. Values of I k decreased slightly in the block culture, increased slightly in the sinusoidal culture and showed a twofold increase in the oscillating culture. From the ratio of in situ oxygen production (qO2) and P max we infer a balanced equilibrium between photosystem activity and electron transport capacity for the block and sinusoidal culture. We hypothesize that the qO2 values of the oscillating culture underestimated true oxygen production rates due to a nonlinear response at peak light intensities. The results show that a dynamical photoperiod provoked significantly different photosynthetic responses, even though the overall growth rate was unaffected.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    ISSN: 1573-5117
    Keywords: streams ; arctic ; tundra ; epilithon ; photosynthesis ; respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthesis and respiration by the epilithic community on cobble in an arctic tundra stream, were estimated from oxygen production and consumption in short-term (4–12 h), light and dark, chamber incubations. Chlorophyll a was estimated at the end of each incubation by quantitatively removing the epilithon from the cobble. Fertilization of the river with phosphate alone moderately increased epilithic chlorophyll a, photosynthesis, and respiration. Fertilization with ammonium sulfate and phosphate, together, greatly increased each of these variables. Generally, under both control and fertilized conditions, epilithic chlorophyll a concentrations (mg m−2), photosynthesis, and respiration (mg O2 m−2, h−1) were higher in pools than in riffles. Under all conditions, the P/R ratio was consistent at ∼ 1.8 to 2.0. The vigor of epilithic algae in riffles, estimated from assimilation coefficients (mg O2 [mg Chl a]−1 h−1) was greater than the vigor of epilithic algae in pools. However, due to the greater accumulation of epilithic chlorophyll a in pools, total production (and respiration) in pools exceeded that in riffles. The epilithic community removed both ammonium and nitrate from water in chambers. Epilithic material, scoured by high discharge in response to storm events and suspended in the water column, removed ammonium and may have increased nitrate concentrations in bulk river water. However, these changes were small compared to the changes exerted by attached epilithon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    ISSN: 1573-5044
    Keywords: cell cycle ; DNA content ; embryogenic competence ; flow cytometry ; mitotic activity ; somatic embryogenesis ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Embryogenic competence of maize (Zea mays L.) leaf tissues was studied with regard to leaf age, distance from leaf base, mitotic activity, 2C nuclear DNA content, and the distribution of cells within the cell cycle. The highest embryogenic competence was observed in the first segment of the second innermost leaf. In a succession of 8 mm segments from the leaf base, the frequency of cells in the G0/G1 phase of the cell cycle and mitotic activity decreased with leaf age and with the distance from leaf base. No significant differences in 2C nuclear DNA content were found for leaf segments of different age and position. The mean 2C nuclear DNA content was 5.74 pg. The results suggested that the loss of embryogenic competence in mature maize leaf tissues is not related to changes in nuclear DNA content, and that the competence is not simply related to a certain distribution of cells within the cell cycle or to a certain level of mitotic activity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    ISSN: 1440-1703
    Keywords: carbon isotope ratio ; photosynthesis ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Primary production by phytoplankton in the eutrophic Mikawa Bay, Japan, was studied by simultaneous measurements of natural carbon isotope ratio (δ 13C) and short-term carbon uptake rates (13C tracer study) of size-fractionated nannoplankton (〈10 μm) and net plankton (〉10 μm) samples. Short-term photosynthetic rates, which represent the physiological state of algae, were variable regardless of standing stock sizes. Theδ 13C values of particulate organic carbon (POC) in June and July displayed horizontal variations for both the net plankton fraction (−19.8 to −12.7‰) and the nannoplankton fraction (−22.0 to −12.8‰). For both fractions, low concentrations of POC had more negativeδ 13C values (−22 to −18‰). Highδ 13C values for the net plankton were found when POC concentrations were much higher, due to red tide. This suggests that the increase in algal standing crop for the net plankton fraction resulted from accelerated photosynthetic activity. However the nannoplankton fractions with higher POC values have relatively lowδ 13C values.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 18 (1992), S. 1981-1990 
    ISSN: 1573-1561
    Keywords: Allelopathy ; ferulic acid ; amylase ; maltase ; invertase ; acid protease ; acid phosphatase ; Zea mays ; growth ; root ; shoot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ferulic acid was tested for its effect on the growth of root and shoot, fresh and dry weights, and hydrolytic enzyme activities of germinating maize seeds. The results showed that root growth was inhibited more than shoot growth. A significant reduction in the activities of hydrolytic enzymes was also observed, which reflects a mechanism of action for the natural growth inhibitors, which may include other phenolic compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    ISSN: 1573-1561
    Keywords: Hessian fly ; Mayetiola destructor ; Diptera ; Cecidomyiidae ; oviposition stimulants ; wheat ; rye ; barley ; oat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract More than twice the number of mated female Hessian flies,Mayetiola destructor (Say) entered a zone within 1 cm of a paper strip treated with one plant equivalent (PE) of a chloroform extract of wheat foliar waxes compared to a strip treated with solvent only; females also stayed six times longer and laid 10 times more eggs on the strip treated with the wheat extract. Column chromatographic fractionation of the wheat extract and application of these fractions onto filter paper strips showed four fractions elicited significant numbers of eggs to be laid. Single, binary, and tertiary combinations of three of these fractions (two of the four fractions apparently contained similar compounds) were tested. The greatest numbers of eggs were laid on strips treated with the tertiary combination or the binary combination conaining the two most active fractions (3 and 6); three times the number of eggs were laid on strips treated with this binary combination than the sum of eggs laid on strips treated with these two fractions separately. A comparison of grasses and their extracts showed female Hessian flies laid greater numbers of eggs on wheat or rye than on barley or oat. Fractionated barley and oat extracts were tested for activity as for wheat, and a similar pattern was observed, i.e., the greatest numbers of eggs were laid on fractions 3 and 6. Dose-response tests, using these two fractions of wheat, barley, or oat showed the same threshold of activity for fraction 3 for all three extracts, i.e., 2 PE. In contrast, fraction 6 of wheat was active at the lowest dosage tested, 0.25 PE, while the same fraction of either barley or oat was not active until tested at a dosage of 2 PE. It appears that (at least) two chemicals in the foliar waxes of these grasses influence ovipositional behavior of female Hessian flies. Furthermore, given the similar foliar chemistry of these grasses and the strong synergistic interaction between fractions 3 and 6 shown for wheat extract, it is likely that the ovipositional preferences exhibited by female Hessian flies towards these grasses may be explained by quantitative differences in the amount(s) of the active chemical(s) in their respective fraction 6 (most polar fraction tested).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 18 (1992), S. 841-846 
    ISSN: 1573-1561
    Keywords: Rhopalosiphum padi ; Homoptera ; Aphididae ; wheat ; maize ; DIMBOA ; hydroxamic acids ; aphid honeydew
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract DIMBOA glucoside (2-O-/gb-D-glucopyranosyl-4-hydroxy-7-meth-oxy-1,4-benzoxazin-3-one), the main hydroxamic acid (Hx) in intact wheat plants, was detected in the honey dew ofRhopalosiphum padi feeding on seedlings of six wheat cultivars that differed in their concentration of Hx, suggesting that the chemical circulates in the phloem. Neither the aglucone (DIMBOA) nor its main breakdown product were found in any of the honeydew samples. Honey dew production by aphids caged on seedlings of the wheat cultivars and DIMBOA glucoside concentrations in the honeydew followed biphasic curves when plotted against Hx concentration, suggesting passive ingestion of the chemical from the phloem at low Hx concentrations and limited ingestion due to feeding deterrency by Hx in mesophyll cells at high Hx concentrations. The presence of plant toxins such as Hx glucosides in the phloem sap, the main ingesta of aphids, and in the mesophyll cells, has major implications for plant defense, through a feeding deterrent effect during stylet penetration, and deterrency (antixenosis) along with antibiosis during feeding.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 18 (1992), S. 897-905 
    ISSN: 1573-1561
    Keywords: Pollen ; corn ; Zea mays ; teosinte ; Zea mexicana ; allelopathy ; phenylacetic acid ; phytotoxicity ; Amaranthus leucocarpus ; Echinochloa crusgalli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Phenylacetic acid (PAA), one of the phytotoxic compounds in corn (Zea mays) pollen, was identified by GC-MS and by direct comparison with a pure commercial sample of PAA. Bioassays were carried out by testing whole pollen, methylene chloride extract of the pollen, and pure PAA on germination and radical growth ofAmaranthus leucocarpus andEchinochloa crusgalli. The effect of corn pollen was compared with that ofZea mexicana (Teosinte), one of the wild relatives of cultivated maize.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...