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  • Articles  (90)
  • Drosophila  (47)
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  • 1984  (42)
  • 1982  (48)
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  • Articles  (90)
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  • 2005-2009
  • 1980-1984  (90)
  • 1965-1969
  • 1925-1929
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  • 1
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    Springer
    Journal of molecular evolution 18 (1982), S. 310-314 
    ISSN: 1432-1432
    Keywords: Neutral mutation theory ; Natural selection ; Protein evolution ; Levene model ; Environmental variability ; Genetic variability ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If a phenotypic character is under stabilizing selection, the selective disadvantage of a nonoptimal genotype will decrease exponentially to zero as the proportion of phenotypic variation that is environmental in origin -V e /V p - increases. Under the modified mutation-drift hypothesis of genetic polymorphism, the proportion of mutations that are effectively neutral and average heterozygosity should increase with this ratio. Invertebrates, because of their small size, fast development, and low degree of homeostasis (relative to vertebrates), are expected to show a larger environmental component of phenotypic variation than vertebrates. This may help explain why invertebrates are in general more genetically variable than vertebrates and why, when laboratory populations ofDrosophila are maintained in heterogeneous environments, genetic variability is lost less rapidly than when they are kept in constant conditions.
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  • 2
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    Journal of molecular evolution 20 (1984), S. 251-264 
    ISSN: 1432-1432
    Keywords: Drosophila ; Genome evolution ; 68C Glue gene cluster ; Drosophila melanogaster species subgroup
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 68C puff is a highly transcribed region of theDrosophila melanogaster salivary gland polytene chromosomes. Three different classes of messenger RNA originate in a 5000-bp region in the puff; each class is translated to one of the salivary gland glue proteins sgs-3, sgs-7, or sgs-8. These messenger RNA classes are coordinately controlled, with each RNA appearing in the third larval instar and disappearing at the time of puparium formation. Their disappearance is initiated by the action of the steroid hormone ecdysterone. In the work reported here, we studied evolution of this hormone-regulated gene cluster in themelanogaster species subgroup ofDrosophila. Genome blot hybridization experiments showed that five other species of this subgroup have DNA sequences that hybridize toD. melanogaster 68C sequences, and that these sequences are divided into a highly conserved region, which does not contain the glue genes, and an extraordinarily diverged region, which does. Molecular cloning of this DNA fromD. simulans, D. erecta, D. yakuba, andD. teissieri confirmed the division of the region into a slowly and a rapidly evolving protion, and also showed that the rapidly evolving region of each species codes for third instar larval salivary gland RNAs homologous to theD. melanogaster glue mRNAs. The highly conserved region is at least 13,000 bp long, and is not known to code for any RNAs.
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  • 3
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    Development genes and evolution 193 (1984), S. 267-282 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a search for embryonic lethal mutants on the second chromosome ofDrosophila melanogaster, 5764 balanced lines isogenic for an ethyl methane sulfonate (EMS)-treatedcn bw sp chromosome were established. Of these lines, 4217 carried one or more newly induced lethal mutations corresponding to a total of 7600 lethal hits. Eggs were collected from lethal-bearing lines and unhatched embryos from the lines in which 25% or more of the embryos did not hatch (2843 lines) were dechorionated, fixed, cleared and scored under the compound microscope for abnormalities of the larval cuticle. A total of 272 mutants were isolated with phenotypes unequivocally distinguishable from wild-type embryos on the basis of the cuticular pattern. In complementation tests performed between mutants with similar phenotype, 48 loci were identified by more than one allele, the average being 5.4 alleles per locus. Complementation of all other mutants was shown by 13 mutants. Members of the complementation groups were mapped by recombination analysis. No clustering of loci with similar phenotypes was apparent. From the distribution of the allele frequencies and the rate of discovery of new loci, it was estimated that the 61 loci represent the majority of embryonic lethal loci on the second chromosome yielding phenotypes recognizable in the larval cuticle.
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  • 4
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    Development genes and evolution 193 (1984), S. 90-97 
    ISSN: 1432-041X
    Keywords: Drosophila ; Temperature-sensitive ; Neoplasms ; Differentiation ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary EMS induced temperature-sensitivelethal (2) giant larva, 1(2)gl, alleles were isolated by screening against a knownl(2)gl allele. Analysis of the lethal phase of thel(2)gl ts-deficiency heterozygotes demonstrated: (1) the majority of thel(2)gl tslarvae survive to late third instar, (2) at 29°C the majority of thel(2)gl tslarvae failed to pupate and only rarely did they differentiate adult cuticular structures, (3) at 15°C the majority of the larvae pupated and frequently differentiated adult cuticular structures. Examination of the imaginal discs ofl(2)gl tslarvae reared at 29°C revealed the presence of morphologically abnormal wing, haltere and leg imaginal discs. No morphologically abnormal discs were found in thel(2)gl tslarvae reared at 15°C. Studies on both the histology and the developmental capacity of the morphologically normal and abnormall(2)gl tsdiscs were performed. The morphologically normal discs are histologically normal and produce a full complement of adult cuticular structures. However, the morphologically abnormal discs contained both regions that maintained the normal monolayer epithelium and regions that had lost the normal tissue architecture. The implants obtained when the morphologically abnormal discs are injected into metamorphosing larvae contained only a limited number of the normal complement of adult structures and usually only structures found in the ventral wing hinge region were recovered. In addition, the “metamorphosed” morphologically abnormal discs contained undifferentiated tissue that gave rise to transplantable neoplasms when cultured in adults. The results of the studies on the pathology of thel(2)gl tslarvae are discussed with respect to the role of thel(2)gl tsfunction during normal development, the autonomy of the neoplastic development of thel(2)gl tstissues, and similarities between neoplastic development inDrosophila and mammals.
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  • 5
    ISSN: 1432-041X
    Keywords: Drosophila ; Pole cell transplantation ; Heterospecific combinations ; Gametogenesis ; Chorion morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We transplanted pole cells betweenDrosophila melanogaster, D. mauritiana andD. ananassae to investigate the ability of germ cells to develop in the gonad of a heterospecific host, and to study the interaction between somatic follicle cells and the cells of the germ line in producing the species-specific chorion. FemaleD. mauritiana germ cells in aD. melanogaster ovary produced functional eggs with normal development potential. The same is true for the reciprocal combination. FemaleD. ananassae pole cells in aD. melanogaster host only developed to a very early stage and degenerated afterwards. None of the interspecific combinations of male pole cells led to functional sperm. We could not determine at what stage the transplanted male pole cells were arrested. The cooperation of follicle cells and the oocyte-nurse cell complex in producing the chorion was studied using the germ-line-dependent mutationfs(1) K10 ofD. melanogaster, which causes fused respiratory appendages and an abnormal chorion morphology. Wild-type femaleD. mauritiana germ cells in a mutantfs(1) K10 D. melanogaster ovary led to the production of wild-type eggs withD. melanogaster-specific, short respiratory appendages. On the other hand,D. melanogaster fs(1) K10 germ cells in aD. mauritiana ovary induced the formation of eggs with mutant fused appendages which were, however, typicallyD. mauritiana in length. When.D. mauritiana pole cells developed in aD. melanogaster ovary, the chorion exhibited a new imprint pattern that differs from both species-specific patterns.
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  • 6
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    Development genes and evolution 191 (1982), S. 285-288 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; homoeosis ; Compartments ; Aldehyde oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The aldehyde oxidase staining pattern in wing discs ofDrosophila melanogaster bearing the genotypesap blt /ap blt andap blt andap blt /ap 73n showns changes from the wild-type pattern. Extensive areas of the presumptive dorsal posterior wing blade, which are normally unstained, have enzyme activity in these mutants. In wings of these genotypes, dorsal posterior structures are replaced by dorsal anterior wing structures. A strong correlation has been found between the frequencies of various staining patterns in the discs and the extent of transformation in the cuticular structures of the wing, which is consistent with the idea that aldehyde oxidase activity can be used as an indicator in the wing disc of this transformation. Unlike the homoeotic mutationengrailed, apterous has not been interpreted as a selector gene yet the work reported here shows thatapterous alleles can cause changes resembling those of theengrailed phenotype both in aldehyde oxidase staining behaviour and in the cuticular transformation.
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  • 7
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    Development genes and evolution 191 (1982), S. 264-269 
    ISSN: 1432-041X
    Keywords: Drosophila ; Sexcombless ; Foreleg basitarsus ; Genital disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chromosome which carries the mutationsexcombless (In(1)sx) affects males and females ofD. melanogaster. In the male foreleg basitarsi the number of sexcomb teeth is dramatically reduced from 10 to 0.7 and the number of transverse rows of bristles is increased from 6 to 8. Females homozygous forIn(1)sx show a normal bristle pattern in the foreleg basitarsus. The genital disc derivatives of both male and femaleIn(1)sx flies are strongly affected. While the external genitalia show a duplicated or a reduced bristle pattern, the internal genitalia are mostly absent. However, the sexually dimorphic tergites and sternites of the abdomen remain unaffected. The male-specific effect on the basitarsus and the general effects on the genital disc derivatives are proposed to represent two different phenotypic effects ofIn(1)sx which may derive from mutations at different gene loci in the inverted chromosome.
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  • 8
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    Development genes and evolution 191 (1982), S. 289-291 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Cell competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imaginal wing discs from late third-instar larvae were gammairradiated to induce clones of rapidly growingMinute − cells in a background of slowly growingMinute cells and culturedin vivo for periods up to 18 days. Clones in discs cultured for 16 to 18 days did not grow significantly larger than clones in uncultured controls, indicating that competition between populations of cells having potentially different mitotic rates does not occur in imaginal discs after their growth is completed.
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  • 9
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    Development genes and evolution 193 (1984), S. 98-107 
    ISSN: 1432-041X
    Keywords: Drosophila ; Neoplasms ; Promotion ; Regeneration ; Temperature-sensitive ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper we present an analysis of the behavior ofl(2)gl tsimaginal wing discs during culture in adult hosts. Thel(2)gl tslarvae reared at 29° C contain two types of wing discs, those that are morphologically normal and those that are abnormal. When discs of both types are cultured in adult hosts at 29° C, the restrictive temperature, they give rise to transplantable neoplastic tissue. However, when the 29° C reared discs are cultured at 15° C, the permissive temperature, the morphologically normal discs maintain their morphology, but the morphologically abnormal discs give rise to neoplasms. Thel(2)gl tslarvae reared at 15° C contain only morphologically normal discs. When these discs are cultured in adult hosts at 29° C they give rise to neoplasms, however if the discs are cultured at 15° C they maintain their normal morphology. These results demonstrate: (1) that all wing imaginal discs obtained from 29° C rearedl(2)gl tslarvae are competent to undergo neoplastic development, (2) the morphologically abnormal discs obtained from the 29° C rearedl(2)gl tslarvae are committed to neoplastic development, (3) the neoplastic development of the morphologically normal discs is temperature dependent, (4) once the neoplastic development of thel(2)gl tsdiscs has been initiated the process is not readily reversible. In addition, the ability ofl(2)gl tswing discs to perform epimorphic regulation was tested by amputating morphologically normal permissively rearedl(2)gl tswing discs and culturing both fragiments at the permissive temperature. Fragments of control wild-type discs maintained their morphology during culture at the permissive temperature. However, both fragments of txel(2)gl tsdiscs became neoplastic. This result is discussed with respect to a possible role for thel(2)gl +function in epimorphic regulation and with respect to the phenomena of tumor promotion in vertebrates.
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  • 10
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    Development genes and evolution 191 (1982), S. 103-111 
    ISSN: 1432-041X
    Keywords: Drosophila ; Polytene Chromosomes ; Ecdysteroids ; Fat Body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in polytene chromosome 3 L puffing patterns in the fat body ofDrosophila melanogaster larvae and prepupae are compared to those in the salivary gland. While some general features are common to the two tissues, there are differences which reflect their different developmental roles. In vitro experiments with fat body chromosomes show that they have a distinct response to ecdysteroids which is different from that of salivary gland chromosomes, and which does not,in this culture system, reproduce the changes observed in normal development. In short term culture experiments, the fat body chromosomes appear more sensitive to ecdysteroids than the salivary gland chromosomes and, although 20-OH ecdysone is more active than ecdysone in these assays, the possibility is not excluded that ecdysone has a role in normal development as it appears to alter gene activity at physiological levels in these cells.
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  • 11
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    Development genes and evolution 191 (1982), S. 293-300 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Positional information ; Homology ; Intercalary regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The regulative behavior of fragments of the imaginal discs of the wing and first leg was studied when these fragments were combined with fragments of other thoracic imaginal discs. A fragment of the wing disc which does not normally regenerate when cultured could be stimulated to regenerate by combination with certain fragments of the haltere disc. When combined with a haltere disc fragment thought to be homologous by the criteria of morphology and the pattern of homoeotic transformation, such stimulated intercalary regeneration was not observed. Combinations of first and second leg disc fragments showed that a lateral first leg fragment could be stimulated to regenerate medial structures when combined with a medial second leg disc fragment but not when combined with a lateral second leg disc fragment. Combinations of wing and second leg disc fragments showed that one fragment of the second leg disc is capable of stimulating regeneration from a wing disc fragment while another second leg disc fragment fails to stimulate such regeneration. It is suggested that absence of intercalary regeneration in combinations of fragments of different thoracic imaginal discs is a result of homology or identity of the positional information residing in the cells of the fragments. The pattern of correspondence of positional information revealed by this analysis is consistant with the pattern of homology determined by morphological observation and by analysis of the positional specificity of homoeotic transformation among serially homologous appendages. The implications of the existence of homologous positional information in wing and second leg discs which share a common cell lineage early in development are discussed.
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  • 12
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    Development genes and evolution 191 (1982), S. 335-339 
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Wing disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of gap junctions in mature larvalDrosophila melanogaster wing discs was analyzed by means of quantitative electron microscopy. Gap junctions are non-randomly distributed in the proximal-distal disc axis and in the apical-basal cell axis of the epithelium. In the epithelial cells, the surface density, number and length of gap junctions are greatest in the apical cell region and distal disc region. The average gap junction surface density is 0.0572 μm−1 and 2.77% of the lateral cell surface is composed of gap junctions. In the adepithelial cells, the gap junction surface density is 0.0005 μm−1 and 0.06% of the cell surface is composed of gap junctions. No gap junctions were observed between epithelial cells and adepithelial cells. The absolute area of gap junctions was estimated in a proximal-distal strip of cells in the disc and is considerably less in the folded regions of the epithelium compared to the flat notum and wing pouch regions. The results are discussed with respect to pattern formation and growth control in imaginal discs.
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  • 13
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    Development genes and evolution 191 (1982), S. 28-36 
    ISSN: 1432-041X
    Keywords: Drosophila ; Polarity ; Maternal effect ; Nurse cells ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationdicephalic (dic) affects follicle development and thereby alters the antero-posterior polarity of embryonic patterning. It maps at a single locus (3–46.0±1.0) and can be characterized as a semi-dominant maternal effect mutation with low penetrance. Indic follicles, the 15 nurse cells form two clusters located at opposite poles of the oocyte; the numerical distribution of the nurse cells among the clusters varies from 7:8 to 1:14. Thedic egg shell carries a micropyle (anterior marker) at either pole, but the misshapen respiratory appendages are restricted to one of the two poles in most eggs. The malformed eggs rarely yield larvae and these are always abnormal anteriorly and/or posteriorly. The segment pattern expressed in their cuticle may represent two anterior parts of opposite polarities (double head type), two posterior parts of opposite polarities (double abdomen type, rare) or show uniform polarity. Lability of organization at the cystocyte stage appears as the primary developmental defect of the mutant.
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  • 14
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Imaginal disc ; Pattern formation ; EM Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Developmental changes in the distribution of gap junctions in early, mid and late third larval stage wing discs and in pupariation+6 h and pupariation+24 h stage wing discs fromDrosophila melanogaster were analyzed by quantitative electron microscopy. Gap junctions occur in all 12 intradisc regions examined in each of the five developmental stages. Their distribution is non-random and changes during development which suggests that they are developmentally regulated. The gap junctions are not static structures, rather they grow and regress during development. The changes tend to be gradual ones without sudden increases or decreases. Gap junctions continuously form and grow in size throughout the third larval stage and during the first 6 h following pupariation. Their surface density, number, percent of the lateral plasma membrane area, and absolute area as well as the lateral plasma membrane surface density all increase during this time. Between pupariation+ 6 h and pupariation+24 h all but one of these parameters decrease indicative of gap junctional breakdown. Gap junctions are most numerous and change least during development in the apical cell regions where intercellular contacts are close and stable. They change most in the basal cell regions where intercellular contacts tend to be looser and change during development. The most dramatic change is in the absolute area which increases by a factor of 23 between the early third larval stage and pupariation+24 h. At pupariation the rate of gap junction growth undergoes a transient increase before the phase of disassembly begins. Developmental changes in gap junction surface density are closely coupled with changes in the lateral plasma membrane surface density which suggests that these may be coregulated. Evidence from mutants suggests that when the number and density of gap junctions fail to increase in proportion to lateral plasma membrane growth, wing disc development will be abnormal. Our results support the idea that some minimum gap junction density is required for normal development and that this must increase as development proceeds. The results are consistent with the notion that gap junctions are involved in pattern formation and growth control and are discussed with respect to the acquisition of competence for metamorphosis, disc growth, disc morphogenesis and changes in the hormonal environment.
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  • 15
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    Development genes and evolution 191 (1982), S. 42-55 
    ISSN: 1432-041X
    Keywords: Clonal analysis ; Growth ; Cell lineage ; Genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InDrosophila, the terminalia (i.e. internal and external analia and genitalia, except the gonads) are formed by the genital disc. Comparative studies suggested that this disc may have evolved through fusion of the imaginal primordia of the last 3 or 4 abdominal segments. The present report describes the clonal relationships within the complex genital disc. Genetically marked cell clones were induced in male and female embryos and larvae heterozygous for cell marker mutations. 1) Frequencies and sizes of clones suggest that the embryonic disc anlage consists of 14–17 precursor cells: 4–6 for the analia, some 7 for the male genitalia, and 3–4 for the female genitalia. These cells grow exponentially during larval development. 2) In both sexes, the clones were confined to either analia or genitalia, suggesting two separate cell lineages already established at blastoderm. 3) Internal and external genitalia remain in the same compartment at least up to 60 h (end of first instar). 4) A clonal restriction appeared around 84 h (mid second instar), separating a dorsal from a ventral part in the male genitalia. The ventral compartment comprises the ventral part of the lateral plate and clasper, hypandrium, and all internal genitalia. No such boundary was detected in the female. 5) In the female, analia and parovaria originate from the same precursors; another cell lineage forms eighth tergites, vaginal plates, oviduct, receptacle, and spermathecae. 6) In female analia, dorsal and ventral plate share common precursors at least up to 84 h. A medio-lateral boundary may appear at 84 h in the ventral anal plate. No clonal restriction was found in the male analia. 7) At all times, clones could cross between left and right sides of the symmetrical terminalia; they consistently did so via ventral structures. 8) The results are discussed in a phylogenetic context, and we propose that the clonal relations reflect the evolution of the complex genital disc.
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  • 16
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    Development genes and evolution 191 (1982), S. 191-201 
    ISSN: 1432-041X
    Keywords: Neurogenic mutants ; Maternal effects ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The size of the neurogenic region ofDrosophila melanogaster is under the control of several genes of zygotic expression. Lack of function from any of those genes produces an increase of the size of the neurogenic region at the expense of the epidermal anlage. However, differences exist in the extent of neuralisation achieved by each of the genetic loci upon mutation. The present results show that in the case ofN andmam phenotype differences are due to different contributions of maternal gene expression. This could be shown by studying the phenotype which appeared in mutant embryos when the oocytes developed from homozygous mutant precursor cells. Clones of mutant cells were induced in the germ line of females heterozygous for the neurogenic mutationin trans over germ line dependent, dominant female sterile mutations. After removing maternal information the phenotype ofN andmam mutants became identical in both cases. Furthermore maternal information fromN + was found to be necessary for viability of the wildtype.
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  • 17
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    Development genes and evolution 191 (1982), S. 211-214 
    ISSN: 1432-041X
    Keywords: Drosophila ; Clonal analysis ; Sex determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationSxl f , located on the X-chromosome, is a sex-limited recessive lethal that specifically kills 2X; 2A flies while it does not affect X; 2A flies (Cline 1978). We have analyzed the role ofSxl f on sex determination by a clonal analysis of a new spontaneous allele,Sxl fLS . Female embryos and larvae heterozygous forSxl fLS were irradiated at different times of development to generate homozygousSxl fLS clones which were recognized by linked marker mutations. We have studied the phenotype of such clones on sexually dimorphic regions of the fly (foreleg basitarsus, 5th, 6th and 7th tergites, analia and external genitalia). Despite their female (2X; 2A) chromosomal constitution, clones homozygous forSxl fLS differentiated male structures. These results confirm and extend the preliminary report of Cline (1979). They show that the wildtype product ofSxl f is required for female development.
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  • 18
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    Development genes and evolution 193 (1984), S. 296-307 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In order to identify X-chromosomal genes required inDrosophila for early patterning and morphogenesis, we examined embryos hemizygous for EMS-induced lethal mutations to determine which of those mutations cause gross morphological defects. Embryos from 2711 lethal lines, corresponding to 3255 lethal point mutations were studied. Only 21% caused death during embryogenesis and of these, only one-sixth, or 3% of the total lethals, were associated with defects visible in the final cuticle pattern. Of the 114 point mutants causing visible cuticle defects, 76 could be assigned to 14 complementation groups. An additional 25 mutations mapping to regions of the X-chromosome not covered by male fertile duplications were assigned to six complementation groups based on similarities of map position and phenotype. Thirteen mutations could not be assigned to complementation groups. All mutations allowed normal development through the cellular blastoderm stage, the first defects associated with the earliest acting loci being observed shortly after the onset of gastrulation. The phenotypes of the various loci range from alterations in segment pattern or early morphogenetic movements to defects in final pigmentation and denticle morphology. Cuticle preparations were also examined for 63 deletions spanning in total 74% of the X-chromosome, as well as for 8 deletions and point mutations derived in saturation mutagenesis screens of the fourth chromosome (Hochman 1976). With the exception of defects in head morphology and defects in cuticle differentiation, none of the hemizygous deletions showed phenotypes other than those predicted by point mutations known to lie in those regions. No deletion caused new or unknown alterations in gastrulation, segmentation or cuticle pattern.These results suggest that the number of genes required zygotically for normal embryonic patterning is small and that most, if not all such loci, are represented by point mutations in our collection.
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  • 19
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The thin region of the peripodial membrane is confined to the area overlying the distal anlagen in thoracic discs. During the early stages of evagination the peripodial membrane is greatly stretched, but does not rupture. The appendage then evaginates through the stalk, probably by means of a contraction of the peripodial membrane. The cells of the peripodial membrane of leg and wing discs persist and differentiate sheets of trichomes characteristic of the ventral and lateral thorax. This is discussed in relation to imaginal disc fate maps.
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  • 20
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    Development genes and evolution 193 (1984), S. 263-265 
    ISSN: 1432-041X
    Keywords: Drosophila ; Biothorax complex ; Prothoracic transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If, early in development, theUbx + gene is removed by mitotic recombination from cells of the meso-and metathoracic leg primordia, theseUbx − cells develop as in the posterior prothoracic leg. We show that this transformation, termedpostprothorax, is a discrete genetic function that is independent of other homeotic transformations such asbx, pbx orbxd, which also result from the inactivation of theUbx gene.
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  • 21
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    Development genes and evolution 193 (1984), S. 283-295 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The present report describes the recovery and genetic characterization of mutant alleles at zygotic loci on the third chromosome ofDrosophila melanogaster which alter the morphology of the larval cuticle. We derived 12600 single lines from ethyl methane sulfonate (EMS)-treatedst e orrucuca chromosomes and assayed them for embryonic lethal mutations by estimating hatch rates of egg collections. About 7100 of these lines yielded at least a quarter of unhatched eggs and were then scored for embryonic phenotypes. Through microscopic examination of unhatched eggs 1772 lines corresponding to 24% of all lethal hits were classified as embryonic lethal. In 198 lines (2.7% of all lethal hits), mutant embryos showed distinct abnormalities of the larval cuticle. These embryonic visible mutants define 45 loci by complementation analysis. For 32 loci, more than one mutant allele was recovered, with an average of 5.8 alleles per locus. Complementation of all other mutants was shown by 13 mutants. The genes were localized on the genetic map by recombination analysis, as well as cytologically by complementation analysis with deficiencies. They appear to be randomly distributed along the chromosome. Allele frequencies and comparisons with deficiency phenotypes indicate that the 45 loci represent most, if not all, zygotic loci on the third chromosome, where lack of function recognizably affects the morphology of the larval cuticle.
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  • 22
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    Development genes and evolution 193 (1984), S. 308-325 
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Pattern of neuroblasts ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper deals with morphological aspects of early neurogenesis inDrosophila, in particular with the segregation of neuroblasts from the neurogenic region of the ectoderm and the pattern formed by those wells within both the germ band and the procephalic lobe. The neurogenic ectoderm was found to contain neural precursors intermingled with epidermal precursors, extending from the midline up to the primordia of the tracheal tree along the germ band and laterodorsally in the procephalic lobe. Germ band neuroblasts segregate from the neurogenic ectoderm during a period of several hours according to characteristic spatial and temporal patterns. During the first half of the segregation process the pattern of germ band neuroblasts was found to be the same in different animals in both spatial arrangement and number of cells; this permitted the identification of individual neuroblasts from different embryos. Later in development several difficulties were encountered which precluded an exact description of the neuroblast pattern. The constitution of the neurogenic region is discussed in relation to the phenotype of mutants affecting neurogenesis.
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  • 23
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    Development genes and evolution 193 (1984), S. 388-393 
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Ring canals ; Oocyte determination ; Polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.
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  • 24
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    Development genes and evolution 193 (1984), S. 406-413 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fusion of the eye-antennal discs during culturein vitro has been investigated, and the complex morphogenetic movements which occur during the formation of the head capsule of the insect are described. The initial contact between the eye anlagen is by means of cell processes spanning the gap between the two discs. Subsequently the two epithelia become firmly apposed, and then the integrity of the epithelium in the region of fusion breaks down, cells appearing to move to new positions in order to form an epithelium which unites the two discs. The epithelium eventually secretes a pattern of cuticular structures which is continuous between the derivatives of the two discs. Bristles on either side of the line of fusion are perfectly aligned, and structures such as the median ocellus, which are formed jointly by the cells of the two discs, differentiate normally. This is also found when left and right eye-antennal discs of different genotypes are placed side-by-side, indicating that processes of pattern regulation can occur in culture.
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  • 25
    ISSN: 1573-4927
    Keywords: aldehyde oxidase ; pyridoxal oxidase ; tissue specificity ; Drosophila
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The substrate specificities of aldehyde and pyridoxal oxidases in Drosophila melanogaster have been determined with a variety of aliphatic and aromatic aldehydes. This analysis has led to the discovery that 2,4,5-trimethoxy-benzaldehyde is a specific substrate for pyridoxal oxidase, as based on the histochemical distribution of oxidase activity, the absence of enzymatic activity in the lpo 1strains, and the dosage dependence on the number of lpo +genes present. The tissue-specific localization of aldehyde oxidase (AO) and pyridoxal oxidase (PO) in the larval and adult structures showed that AO was present in all the major internal organs of the larvae and adults, including brain, imaginal discs, Malpighian tubules, digestive system, and reproductive structures. Pyridoxal oxidase is present in many of the same structures which possess AO, but is missing from the cardia, crop, imaginal discs, ovarian follicle cells, paragonia, pericardial cells, and wreath cells. The only structure which possesses PO but lacks AO is the larval salivary gland. These histochemical differences in AO and PO distribution were also confirmed by enzymatic analysis of the activities present in homogenates of ovaries, paragonia, and salivary glands. The general pattern of enzyme expression appears to be established during embryogenesis and maintained throughout the life of the individual.
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  • 26
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    Biochemical genetics 20 (1982), S. 461-474 
    ISSN: 1573-4927
    Keywords: Drosophila ; allozymes ; α-Gpdh ; selection ; genetic background
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three sets of experiments have been conducted in order to evaluate the role of natural selection at the α-Gpdh locus in Drosophila melanogaster. (1) The evolution of the F-allele frequency has been followed for many generations in 13 experimental populations having different genetic backgrounds. (2) Egg-to-adult viability has been measured in synthetic populations derived from one locality (Brouilly) and the results have been compared with those of a previous experiment involving a different local population (Tostes). (3) The effects of sodium octanoate on egg-to-adult viability have been measured on the genotypes FF, FS, SF, and SS. The results demonstrate that selection operates on a small block of genes which includes the α-Gpdh locus.
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  • 27
    ISSN: 1573-4927
    Keywords: esterase ; duplication ; gene expression ; Drosophila
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An esterase duplication is described in the sibling species pair Drosophila mojavensis and Drosophila arizonensis. We present evidence for two separate structural loci mapping at a distance of less than 0.16 recombination units from each other. Alleles at the two loci have the same substrate specificities and form small amounts of interlocus heterodimers. One locus (Est-5) is functioning throughout the insect's life cycle and appears at high concentrations in the hemolymph and the fat body. Its duplicate (Est-4) functions only during the late larval stage and is concentrated mainly in the carcass. No null alleles at either locus were observed in population surveys. An examination of 12 other species from the repleta group, to which D. mojavensis and D. arizonesis belong, suggests that Est-5 is universally present, but the activity levels of Est-4 vary among species and may be totally absent in some species. Variation in the level of Est-4 activity does not closely follow the phylogenetic relationship.
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  • 28
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    Biochemical genetics 20 (1982), S. 179-198 
    ISSN: 1573-4927
    Keywords: acetylcholinesterase ; Drosophila ; malathion ; insecticide resistance
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relationship between the 50% survival time for flies feeding on a malathion-containing medium and the activity of acetylcholinesterase (AChE) was determined for 15 isofemale lines of Drosophila melanogaster. A significant correlation was found (r=0.28, P〈0.05), with more resistant lines tending to have a lower level of AChE activity. An association between AChE and malathion resistance was also observed in a selection experiment. The AChE activity decreased in two of two populations selected for malathion resistance. AChE from these populations was altered in kinetic parameters (measured in crude head extracts) and electrophoretic mobility. Although the “resistant” AChE had a lower activity (V m) on either a per milligram protein or a per individual basis, its apparent K m for acetylthiocholine was lower than that of “susceptible” AChE. Recombination mapping of both low activity and fast electrophoretic mobility localized these traits to the region of the structural locus (Ace) on the third chromosome. The AChE activity of flies heterozygous for a variety of Ace lesions (kindly provided by Dr. W. M. Gelbart) was consistent with this location. The changes in AChE were suggested to have been caused by selection of alleles at the Ace locus.
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  • 29
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    Biochemical genetics 22 (1984), S. 153-168 
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; activity ratio ; specific activity
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Thirteen Drosophila Adh variants have been characterized with respect to gene expression, substrate preference, thermostability, and specific activity. The results suggest that the variants may be grouped into two biochemical classes, typified by the properties of the two most common enzyme forms, ADH-F and ADH-S. Membership of these classes cannot be predicted from electrophoretic mobility, nor is any simple classification possible with regard to the characteristics of level of gene expression (in terms of ADH activity or ADH protein) or thermostability of the gene product.
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  • 30
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    Biochemical genetics 22 (1984), S. 1015-1029 
    ISSN: 1573-4927
    Keywords: acetaldehyde ; alcohol dehydrogenase ; aldehyde oxidase ; Drosophila
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Metabolic utilization and toxicity of acetaldehyde were studied in flies lacking alcohol dehydrogenase (ADH), aldehyde oxidase (AO), or both functions. Prior to the experiments, mutant alleles Adh n4 and mal were transferred to the same genetic background by 10 successive backcrosses. By comparison with wild-type flies, various deleterious, pleiotropic effects could be attributed to the mal allele but not to Adh n4 . Of the four genotypes studied (mal, Adh n4 , mal Adh n4 , and wild), all were able to use acetaldehyde as a resource in a similar way. In spite of its high toxicity, acetaldehyde appeared a better resource than ethanol. Flies treated with intermediate acetaldehyde concentrations (around 0.5%) exhibited a very high interindividual heterogeneity which could reflect a physiological adaptation occurring as a consequence of the aldehyde treatment. Toxicity tests showed that ADH-negative flies were more sensitive to acetaldehyde than wild type, but this is most likely explained by the transformation of the aldehyde into alcohol. Our results show that the aldehyde metabolizing enzyme (AME) system in Drosophila is neither ADH nor AO. The existence of an aldehyde dehydrogenase is plausible.
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    Biochemical genetics 20 (1982), S. 407-424 
    ISSN: 1573-4927
    Keywords: dipeptidases ; Drosophila ; variation
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three dipeptidases in Drosophila melanogaster are under independent genetic control and their structural genes have been localized, Dip-A to 2R and Dip-B and Dip-C to 3R (Voelker and Langley, 1978; Ohnishi and Voelker, 1981). These enzymes were characterized with respect to their substrate specificities, genetic variability (electrophoretic mobility and quantitative activity level), ontogeny (activity and isozyme pattern), and tissue localization. The dipeptide substrate specificities of DIP-A and DIP-B overlap each other considerably, but do not overlap with DIP-C. In natural populations, DIP-B and DIP-C are essentially monomorphic electrophoretically whereas DIP-A is polymorphic for three allozymes. Both DIP-A and DIP-B show quantitative genetic variation of activity level within an allozyme class. All three enzymes are expressed at all stages in the life cycle, but DIP-A and DIP-B activities vary considerably according to developmental stage and sex of adult. The tissue localizations of DIP-A and DIP-B activities show similar patterns and a nearly ubiquitous occurrence of both enzymes, but with particularly high values in larval and adult midguts and in the adult female reproductive system. These results suggest a general metabolic role for the enzymes, such as regulation of the concentrated pools of amino acids and oligopeptides found in Drosophila tissues.
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    Behavior genetics 14 (1984), S. 279-293 
    ISSN: 1573-3297
    Keywords: phototaxis ; Drosophila ; correlated response ; selection ; sepia
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    Topics: Biology , Psychology
    Notes: Abstract Artificial selection for positive and negative phototaxis was conducted in populations ofDrosophila melanogaster that were polymorphic at thesepia locus. Photoselection response was accompanied by a correlated response in the frequency of thesepia allele. Changes insepia frequency were shown to be significantly different from those predicted by several neutral models. Implications of this correlated response are briefly discussed in terms of the neurogenetic basis of phototaxis.
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    Behavior genetics 14 (1984), S. 315-317 
    ISSN: 1573-3297
    Keywords: Drosophila ; mating and barometric pressure
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    Topics: Biology , Psychology
    Notes: Abstract During a study ofDrosophila mating behavior we observed unexpected changes in performance under ostensibly identical experimental conditions. We related the behavior during the 17 days of the experiment to changes in ambient humidity and barometric pressure. Humidity had no significant effect, but reduced barometric pressure was found to be associated with reduced mating activity (R 2=0.29,P〈0.025), accounting for close to 30% of the variation in total number of matings.
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  • 34
    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; learning ; circadian
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  • 35
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    Behavior genetics 14 (1984), S. 411-440 
    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; pheromones
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  • 36
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    Behavior genetics 14 (1984), S. 527-557 
    ISSN: 1573-3297
    Keywords: Drosophila ; learning ; classical conditioning mutants ; cAMP
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    Behavior genetics 14 (1984), S. 441-478 
    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; pheromones
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    Topics: Biology , Psychology
    Notes: Summary Experimental evidence and speculation relative to chemical messages exchanged byDrosophila during courtship and mating are reviewed. Only the speciesD. melanogaster andD. simulans are considered in detail. Emphasis is put on female aphrodisiacs, as they clearly participate in sex and species recognition. All the aphrodisiac molecules described are unsaturated long-chain hydrocarbons, and position 7 for a double bond seems important in both species. InD. melanogaster, only females are able to make 7,11-dienes, compounds which stimulate males of this species to court. InD. simulans, 7-tricosene plays a similar role but is produced by both sexes as well as maleD. melanogaster. In both species, polymorphism is shown for these molecules. Their biosynthesis is also considered and both preliminary biochemical and genetic data are introduced. Male-specific compounds which regulate male and female behaviors are also reviewed. For example,cis-vaccenyl acetate inhibits male courtship; one or two peptides control the female's receptivity and egg laying. Such compounds are transferred from males to females together with sperm.
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  • 38
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; selection ; ethanol ; temperature
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Drosophila melanogaster larvae were subjected to 10 generations of selection on 6% ethanol at 17, 25, and 30°C. For each temperature there was a significant (P〈0.01) increase in the frequency of the Adh isoallele. Controls with no ethanol showed no change in the frequency of the Adh F isoallele. Larvae subjected to stronger selection on 8% ethanol confirmed the results. When adults of various ages were subjected to 16 and 32°C, the ADHF isoenzyme retained its twofold advantage in activity over ADHS regardless of the temperature. The same result was obtained with larvae at 16 and 35°C. Although some effect of temperature was demonstrated, it was concluded that the effect was not strong enough for temperature to be a selective factor under the conditions studied. However, ethanol is a strong selective factor for laboratory populations.
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  • 39
    ISSN: 1573-3297
    Keywords: assortative mating ; polymorphism ; partner selection ; pheromone ; behavior ; Drosophila
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    Topics: Biology , Psychology
    Notes: Abstract Averhoff and Richardson [(1974)Behav. Genet. 4:207–225] reported a trend toward negative assortative mating inDrosophila melanogaster during the course of inbreeding. These authors proposed that the underlying mechanism was based on pheromone polymorphism and male selection. Mass mating experiments were carried out to verify their hypothesis, detailed behavior observations were made to identify the underlying mechanism, and sex pheromone composition and variation were examined by using gas chromatography-mass spectrometry analysis. The results showed that negative assortative mating is not a general phenomenon. Although male pheromones are probably polymorphic, female pheromones are not. We found no evidence for male selection as predicted by Averhoff and Richardson. It is argued that the most parsimonious mechanism underlying negative assortative mating is similar to one proposed by Bryant [(1979)Behav. Genet. 9:249–256], which was based on interstrain differences in female reluctancy and male vigor.
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    Behavior genetics 14 (1984), S. 153-156 
    ISSN: 1573-3297
    Keywords: mating behavior ; statistical analysis ; Drosophila
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    Topics: Biology , Psychology
    Notes: Abstract Quite different sets of data are shown to generate identical output ratios so that analyses of mating behavior data based on the use of input and output ratios may obscure significant aspects of the mating behavior.
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  • 41
    ISSN: 1573-3297
    Keywords: Drosophila ; learning ; conditioning
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  • 42
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    Theoretical and applied genetics 67 (1984), S. 249-255 
    ISSN: 1432-2242
    Keywords: Wheat ; Plant regeneration ; Chromosome variation
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    Topics: Biology
    Notes: Summary A cytological study has been made of plants regenerated from cultured immature embryos of four wheat cultivars (Triticum aestivum, 2n = 6x = 42). In total, 29% of the 192 plants examined were aneuploid with a range in chromosome numbers of 38–45. Evidence of chromosome structural changes was also found. This variation occurred in regenerants of all four cultivars, but there were large differences in the proportions of aneuploids arising from individual cultures which meant that no significant differences could be demonstrated between cultivars. Chromosome abnormalities were present in plants regenerated both from embryogenic cultures and from cultures in which the origin of shoots could not be distinctly defined.
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    Theoretical and applied genetics 67 (1984), S. 439-442 
    ISSN: 1432-2242
    Keywords: Wheat ; Multicellular pollen grains ; Embryos ; Cytology
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    Topics: Biology
    Notes: Summary Cytological analysis of microspore embryogenesis during in vitro culture reveals a high mortality in the first week and a latency phase of about one week before the first embryogénic mitosis. Genotypic differences observed during our wheat anther culture do not seem to originate at the induction level but are linked to the different abortion rates.
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    Theoretical and applied genetics 67 (1984), S. 525-528 
    ISSN: 1432-2242
    Keywords: Cryopreservation ; Embryo culture ; Haploids ; Wheat ; Rice ; Germplasm bank
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    Topics: Biology
    Notes: Summary Anther culture derived pollen embryos and immature zygotic embryos of wheat and rice, frozen in liquid nitrogen in the presence of dimethyl sulfoxide, sucrose and glycerol, have been revived. The retrieved cultures proliferated and/or regenerated shoots and plantlets. The prospects of the cryopreservation of embryos for the conservation and multiplication of germplasm and the possibility of the establishment of ‘Germplasm Banks’ are discussed.
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    Theoretical and applied genetics 68 (1984), S. 219-226 
    ISSN: 1432-2242
    Keywords: Hexaploid genotypes ; Allelic variation ; Esterase ; Isozymes ; Isoelectric focusing ; Wheat
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    Topics: Biology
    Notes: Summary Analysis of grain esterase isozymes in Chinese Spring aneuploid genotypes by IEF confirmed that genes on the long arms of chromosomes 3A, 3B and 3D (Est-5) control the production of 19 isozymes. Allelic variants have been found for the isozyme pattern controlled by each chromosome. Segregational data involving null alleles and complex phenotypic differences indicate that the wheat grain esterases are encoded by three compound and probably homoeoallelic loci, each capable of producing at least six different isozymes. In a sample of 138 hexaploid genotypes, seven alleles were distinguished.
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  • 46
    ISSN: 1432-2242
    Keywords: Electrophoresis ; Endosperm ; Proteins ; Emmer ; Wheat
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    Topics: Biology
    Notes: Summary Triticum turgidum L. var. dicoccoides (wild emmer) is an important genetic resource for increasing the protein content of common wheat (Triticum aestivum L.). Many studies have shown that the presence or absence of bands in sodium dodecyl sulfate polyacrylamide (SDS-PAGE) electrophoregrams of wheat storage proteins to be of a purely genetic character. A total protein extraction and SDS-PAGE technique was used to estimate the storage protein genetic variability among 841 accessions of wild emmer collected from various ecological regions in the Middle East. In addition, a computer data bank was developed, recording the onedimension electrophoregram bands for each accession by molecular weight (MW) and relative Coomassie Blue staining intensity as determined from densitometer scans. Analyses of this information are being used to identify specific accessions for further study by two dimension electrofocusing-electrophoresis and breeding and genetic analyses. The computer-assisted analyses indicated that the greatest genetic variability occurs for proteins in the high MW region (above 70,000 MW) followed by those in the medium range (70,000 to 33,300 MW). Comparatively little variability was revealed for protein subunits of below 33,300 MW.
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  • 47
    ISSN: 1432-2242
    Keywords: Chromosomal location ; Genetic control ; Salt soluble proteins ; Wheat ; Barley ; Rye
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    Notes: Summary Salt-soluble proteins from the endosperms of wheat, barley, and rye have been separated by nonequilibrium electrofocusing x electrophoresis. Genes encoding 14 of the 25 components observed in wheat have been unambiguously assigned to 10 different chromosomes (1B, 3B, 3D, 4A, 4D, 5B, 6B, 6D, 7B, 7D) by analysis of the compensated nulli-tetrasomic series. Five more wheat proteins seem to be controlled by group 2 chromosomes. Analysis of wheat-barley and wheat-rye addition lines has led to the location of genes for 6 out of 20 barley proteins in 4 different chromosomes (1H, 3H, 4H, 6H; 1H is homoeologous to group 7 chromosomes of wheat) and of genes for 5 out of 20 rye proteins in two different chromosomes (2R, 4R). The relationship between the proteins reported here and previously characterized ones is discussed.
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  • 48
    ISSN: 1432-2242
    Keywords: Wheat ; Triticum ; Grain protein ; Grain weight ; Maternal effect ; Cytoplasmic effect
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    Notes: Summary Reciprocal crosses were made between cultivated wheat (Triticum turgidum var. ‘durum’) and a high-protein line of wild tetraploid wheat (T. turgidum var. ‘dicoccoides’). F1 grains (on maternal spikes) were very similar to the selfed grains on the maternal parent in protein percentage, weight and protein content. These traits were also analyzed in F3 grains developed on F2 spikes of segregating populations derived from reciprocal crosses between the same cultivated parent and another high-protein line of var. ‘dicoccoides’. No significant differences in the mean values of these traits were found between the reciprocal crosses, indicating no cytoplasmic effect. It has been concluded that these grain characteristics are largely determined by the maternal plant.
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  • 49
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    Theoretical and applied genetics 68 (1984), S. 21-23 
    ISSN: 1432-2242
    Keywords: Wheat ; Heritability ; Yield ; Height
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    Topics: Biology
    Notes: Summary Grain yield, plant height and test weight were studied in a population of winter wheat (Triticum aestivum L.). The population consisted of F2 bulk populations of 42 crosses among 11 genotypes adapted to S. W. Ontario. Heritabilities were: 0.30±0.32 for yield, 0.77±0.15 for height and 0.98±0.08 for test weight. Predicted genetic gain with 10% selection intensity was 0.15 t/ha for yield, 10.1 cm for height and 3.00 kg/hl for test weight. The low heritability for yield indicates that effective selection would require pedigree information and progeny tests, while the high heritabilities for height and test weight indicate that selection for these traits using single plots would be appropriate.
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    Theoretical and applied genetics 61 (1982), S. 27-33 
    ISSN: 1432-2242
    Keywords: Preferential transmission ; In situ hybridization ; C-banding ; Aegilops sharonensis ; Wheat ; Addition ; Substitution
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    Topics: Biology
    Notes: Summary An attempt to produce a set of addition lines of Aegilops sharonensis to the wheat variety ‘Chinese Spring’ produced only one addition line. This was due to preferential transmission of one chromosome from Ae. sharonensis. This chromosome was studied in detail by established cytological methods of chromosome observation and by the newer techniques of C-banding and in situ hybridization of a cloned DNA sequence. The chromosome was found to be partially homologous to an Ae. sharonensis chromosome of similar behaviour in another wheat addition line. The incomplete homology of the two Ae. sharonensis chromosomes was due to the presence of a translocated segment of a wheat chromosome. — Substitution lines of the Ae. sharonensis chromosome for wheat homoeologous group 4 were produced and the Ae. sharonensis chromosome thereby designated 4 S l .
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    Theoretical and applied genetics 63 (1982), S. 193-199 
    ISSN: 1432-2242
    Keywords: Drosophila ; Polytene nuclei ; Underreplication ; Polytenization ; Cytophotometry ; Heterochromatin
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    Topics: Biology
    Notes: Summary Recent cytophotometric DNA determinations and results of labeling experiments are compared with results of biochemical experiments concerning larval polytene salivary gland nuclei of Drosophila melanogaster. Recent publications (Dennhöfer 1981; 1982 a, b) demonstrate that methodological errors both in hydrolysis of the DNA before Feulgen reaction and in interpretation of the cytophotometric values give raise to the hypothesis of heterochromatic underreplication during polytenization. It is concluded also that methodological difficulties cause the absence of polytene SAT-DNA in biochemical centrifugation experiments since, because of different solubilities of eu- and heterochromatic DNA, the latter is not resolved in DNA isolation procedures from polytene nuclei.
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    Theoretical and applied genetics 63 (1982), S. 227-233 
    ISSN: 1432-2242
    Keywords: C-banding ; Wheat ; Rye ; Triticale
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    Topics: Biology
    Notes: Summary Using different stains, wheat chromosomes could be distinguished from rye chromosomes by preferential staining. C-bands of rye chromosomes were preferentially stained with Giemsa while those of wheat chromosomes were preferentially stained with either Leishman or Wright stain. Preferential staining aids the identification of wheat and rye chromosomes and chromosome segments and in particular the recognition of wheat/rye chromosome substitutions and translocations.
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    Theoretical and applied genetics 62 (1982), S. 45-48 
    ISSN: 1432-2242
    Keywords: Wheat ; Rye ; Triticale ; Callus cultures ; Alcohol dehydrogenase ; Isoenzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two NAD-dependent alcohol dehydrogenases ADH-1 and ADH-2, under independent genetic control of genes designated as Adh-1 and Adh-2 located on chromosomes 4A, 4B and 4D, have been reported in aestivum wheat (Hart 1980). Only ADH-1 is expressed in developing seeds, dry seeds, pollen and germinating seedlings. ADH-2 can be induced in seedling roots or shoots under conditions of partial anaerobiosis or by certain chemicals. Expression of ADH-1 and ADH-2 isoenzymes was investigated in undifferentiated calli from aestivum and durum wheats, rye, triticale and also in in vitro regenerated roots and leaves from aestivum cultures. Wheat callus cultures originating from seed, mature and immature embryos, mesocotyl and root, as well as cultures grown on media containing different supplements did not show any variation in the overall expression of ADH-1 or ADH-2, although differences in the band intensities were observed. The callus isoenzyme pattern was similar to that observed in roots under anaerobic conditions. Both ADH-1 and ADH-2 were expressed in in vitro regenerated roots but were absent in regenerated leaves. Expression of ADH-1 and ADH-2 in wheat calli seems to be related to the type of differentiation.
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  • 54
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    Theoretical and applied genetics 62 (1982), S. 127-134 
    ISSN: 1432-2242
    Keywords: Wheat ; Genetical analysis ; Cross prediction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Genetical analysis of the F2 triple test cross design combined with conventional early generations was used to elucidate the genetical control of yield and yield components in two crosses of winter wheat. From estimates of the additive, {d}, and additive X additive, {i}, components of means, together with the additive genetical variance, D, predicted frequencies of recombinant inbred lines that would transgress the parental range were calculated for each cross. The accuracy of predictions was evaluated by comparing expected frequencies with observed numbers in populations of F6 lines previously developed by single seed descent. For both crosses and all characters where an adequate genetical model was found to explain the observed variation between the early generations, good agreement between predicted and observed frequencies of transgressive segregants was obtained. Furthermore, for characters exhibiting significant epistasis, allowance for additive X additive {i} epistasis in the prediction equations was sufficient to allow for skewness of the recombinant inbred population. These results demonstrate that cross performance in wheat can be predicted from genetical analysis of early generations, and the value of this approach in breeding new varieties is discussed.
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  • 55
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    Theoretical and applied genetics 62 (1982), S. 121-126 
    ISSN: 1432-2242
    Keywords: Wheat ; Quality ; Dwarfism ; Gibberellin ; α-amylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of the Tom Thumb dwarfing gene, Rht3, on the quality and quantity of grain α-amylase produced during germination and by induction with exogenous gibberellic acid are described. In a season conducive to high sprouting damage the gene reduced α-amylase levels in the field by 77%. Selection among random Rht3 genotypes showed that other genetic factors can be combined with the dwarfing gene to further increase sprouting damage resistance.
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  • 56
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    Theoretical and applied genetics 62 (1982), S. 317-320 
    ISSN: 1432-2242
    Keywords: Wheat ; Rye ; Phosphogluconate dehydrogenase ; Genetic control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 6-phosphogluconate dehydrogenase (6-PGD) zymogram phenotypes of wheat, rye and their aneuploid derivatives were determined. Two genes involved in the production of 6-PGD isozymes were located on chromosome arms CRL (4 RL) and FRL (6 RL) of “Imperial” rye. On the basis of differential interactions between wheat and rye chromosomes, evidence was obtained that genes located on chromosomes 6 A, 6 BL and 7 BL control 6-PGD isozyme activities in ‘Chinese Spring’ wheat. The wheat and rye 6-PGD zymogram phenotypes were indicative of homoeologous relationships between rye chromosome 6 RL to wheat chromosomes of group 6, and rye chromosome 4 RL to wheat chromosomes of group 7.
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  • 57
    ISSN: 1432-2242
    Keywords: HMW storage prolamins ; Wheat ; Rye ; Barley ; Characterization and purification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Homologous high molecular weight storage prolamins were purified from grain of wheat, rye and barley using combinations of gel filtration, ion-exchange chromatography and preparative isoelectric focusing. Sodium dodecylsulphate polyacrylamide gel electrophoresis showed that the components were single bands with apparent mol.wts. of above 100,000. Molecular weights determined by sedimentation equilibrium ultracentrifugation were considerably lower; 54,700, 67,600 and 69,600 for the components from barley, rye and wheat respectively. Amino acid analysis showed the presence of 13.6 to 16.5 mol% glycine, 29.6 to 34.0 mol% glutamate + glutamine, 11.4 to 13.7 mol% proline and a total of 4.0 to 5.7 mol% basic amino acids. Automated N-terminal amino acid sequencing of the component from wheat showed the presence of cysteine residues at positions 5 and 10, and this is discussed in relation to the possible role of these proteins in the visco-elastic gluten network.
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  • 58
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    Theoretical and applied genetics 63 (1982), S. 39-47 
    ISSN: 1432-2242
    Keywords: C-banding ; Wheat ; Triticale ; Heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The C-banding patterns of wheat chromosomes in 7 hexaploid triticale and 7 wheat genotypes are described and compared. All 14 wheat chromosome pairs were individually identified in the triticales and a tetraploid wheat, and all the B and two A genome chromosome pairs in the hexaploid wheat genotypes. Little variation was found between genotypes in the distribution of C-bands but considerable variation was found in their size, total number and total length.
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  • 59
    ISSN: 1432-2242
    Keywords: Wheat ; Agropyron ; Chromosome pairing ; Alcohol dehydrogenase isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The relationships of Agropyron intermedium chromosomes in two wheat-Agropyron addition series were determined. Chromosome pairing behaviour revealed that the alien chromosome in lines TAF-2 and L7 of ‘Vilmorin’-A. intermedium set are homologous to the alien chromosomes in lines P and C of the ‘Caribo’-A. intermedium set respectively. Localization of alcohol dehydrogenase isozyme genes in ‘Vilmorin’-Agropyron addition line L4 and in ‘Caribo’-Agropyron line O indicated relationships with wheat chromosomes of homoeologous group 4.
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  • 60
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    Theoretical and applied genetics 63 (1982), S. 337-348 
    ISSN: 1432-2242
    Keywords: Wheat ; rDNA ; Sequence ; Populations ; Variation ; Spacer region ; Triticum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The wheat rDNA clone pTA250 was examined in detail to provide a restriction enzyme map and the nucleotide sequence of two of the eleven, 130 bp repeating units found within the spacer region. The 130 bp units showed some sequence heterogeneity. The sequence difference between the two 130 bp units analysed (130.6 and 130.8) was at 7 positions and could be detected as a 4 °C shift in Tm when heterologous and homologous hybrids were compared. This corresponded to a 1.2% change in nucleotide sequence per ΔTm of 1 °C. The sensitivity of the Tm analysis using cloned sequences facilitated the analysis of small sequence variations in the spacer region of different Triticum aestivum cultivars and natural populations of T. turgidum ssp. dicoccoides (referred to as T. dicoccoides). In addition spacer length variation was assayed by restriction enzyme digestion and hybridization with spacer sequence probes. Extensive polymorphism was observed for the spacer region in various cultivars of T. aestivum, although within each cultivar the rDNA clusters were homogeneous and could be assigned to particular chromosomes. Within natural populations of T. dicoccoides polymorphism was also observed but, once again, within any one individual the rDNA clusters appeared to be homogeneous. The polymorphism, at the sequence level (assayed by Tm analysis), was not so great as to prevent the use of spacer sequence variation as a probe for evolutionary relationships. The length variation as assayed by restriction enzyme digestion did not appear to be as useful in this regard, since its range of variation was extensive even within populations of a species.
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  • 61
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    Theoretical and applied genetics 63 (1982), S. 349-360 
    ISSN: 1432-2242
    Keywords: Chromosomes ; Nucleotides ; Evolution ; Polyploids ; Triticum ; Heterochromatin ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nature of genome change during polyploid evolution was studied by analysing selected species within the tribe Triticeae. The levels of genome changes examined included structural alterations (translocations, inversions), heterochromatinization, and nucleotide sequence change in the rDNA regions. These analyses provided data for evaluating models of genome evolution in polyploids in the genus Triticum, postulated on the basis of chromosome pairing at metaphase I in interspecies hybrids. The significance of structural chromosome alterations with respect to reduced MI chromosome pairing in interspecific hybrids was assayed by determining the incidence of heterozygosity for translocations and paracentric inversions in the A and B genomes of T. timopheevii ssp. araraticum (referred to as T. araraticum) represented by two lines, 1760 and 2541, and T. aestivum cv. Chinese Spring. Line 1760 differed from Chinese Spring by translocations in chromosomes 1A, 3A, 4A, 6A, 7A, 3B, 4B, 7B and possibly 2B. Line 2541 differed from Chinese Spring by translocations in chromosomes 3A, 6A, 6B and possibly 2B. Line 1760 also differed from Chinese Spring by paracentric inversions in arms 1AL and 4AL whereas line 2541 differed by inversions in 1BL and 4AL (not all chromosomes arms were assayed). The incidence of structural changes in the A and B genomes did not coincide with the more extensive differentiation of the B genomes relative to the A genomes as reflected by chromosome pairing studies. To assay changing degrees of heterochromatinization among species of the genus Triticum, all the diploid and polyploid species were C-banded. No general agreement was observed between the amount of heterochromatin and the ability of the respective chromosomes to pair with chromosomes of the ancestral species. Marked changes in the amount of heterochromatin were found to have occurred during the evolution of some of the polyploids. The analysis of the rDNA region provided evidence for rapid “fixation” of new repeated sequences at two levels, namely, among the 130 bp repeated sequences of the spacer and at the level of the repeated arrays of the 9 kb rDNA units. These occurred both within a given rDNA region and between rDNA regions on nonhomologous chromosomes. The levels of change in the rDNA regions provided good precedent for expecting extensive nucleotide sequence changes associated with differentiation of Triticum genomes and these processes are argued to be the principal cause of genome differentiation as revealed by chromosome pairing studies.
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  • 62
    ISSN: 1615-6102
    Keywords: Cereals ; Immature embryo ; Inflorescence ; Plant regeneration ; Somatic embryogenesis ; Triticwn aestivum L. ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tissue cultures ofTriticum aestivum L. (wheat) initiated from young inflorescences and immature embryos possessed the potential for regeneration of whole plants. Both a friable and a compact type of callus were produced on Murashige and Skoog's medium with 2 mg/l 2,4-dichlorophenoxyacetic acid. The friable callus contained meristematic centers in which the peripheral cells ceased dividing, elongated, and could be easily separated. Roots were frequently formed in this type of callus. The compact, yellowish, and nodular callus arose from the epithelial and sub-epithelial cells of the embryo scutellum, and the rachis and glumes of the young inflorescence. Such callus had a smooth surface and characteristic chlorophyllous areas. Plants were regenerated only from the compact callus. The first sign of differentiation in the compact callus was the formation of a cleft or notch on the smooth surface, followed by the appearance of trichomes and the direct development of leafy structures which were not associated initially with any shoot meristems. Multiple shoots subsequently arose at the bases of the leafy structures, which are considered modifications of the scutellum, a definitive part of the cereal embryo. Accordingly, we suggest that while typical bipolar embryos are generally not formed, plant regeneration nevertheless takes place through embryogenesis and the precocious germination of the embryoids. Plants regenerated from immature embryo and inflorescence cultures were grown to maturity in soil, and were shown to have the normal chromosome number of 2n=6x=42.
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  • 63
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    Behavior genetics 12 (1982), S. 281-293 
    ISSN: 1573-3297
    Keywords: anemotaxis ; Drosophila ; habitat selection ; heritability ; wind-directed movement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Two strains ofDrosophila melanogaster were selected for anemotactic response for six generations—one line for upwind response and one line for downwind response. A realized heritability estimate ofh 2=0.131 ±0.029 was obtained for the upwind response, and a realized heritability estimate ofh 2=0.012±0.014 was obtained for the downwind response. The divergent selection estimate wash 2=0.031±0.013. These values are consistent with previously reported heritability estimates for phototaxis and geotaxis, and serve to suggest that wind-oriented movement can be rapidly modified by selection under different habitat conditions. A comparison of wind response among wild-caught individuals of 11 species shows significant response differences between closely related species. Evaluation of these differences in light of the ecology of the flies suggests that upwind movement occurs among the monophagous species, which must move long distances to find their specific feeding sites, while downwind movement is more typical of polyphagous species. Species which are found in riparian or montane forest conditions showed a general reluctance to move under windy conditions. This corresponds to previous observations on these species and reflects the absence of wind generally encountered by these species during their natural periods of activity.
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  • 64
    ISSN: 1573-5036
    Keywords: Acridine orange ; Cochliobolus sativus ; Common root rot ; Nitrogen fixation ; Nuclear staining ; Roots ; Senescence ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Natural senescence of the root cortex was assessed by nuclear staining, for cultivars and chromosome substitution lines of spring wheat known to differ in (1) susceptibility to common root rot, (2) total rhizosphere populations and (3) ability to support growth of a free-living nitrogen-fixing bacterium. Together, three root rot susceptible wheat lines showed significantly more cortical senescence than did three resistant lines; the susceptible lines also support larger rhizosphere populations. The wheat line that supports growth of a nitrogen-fixing bacterium showed significantly less cortical death than did any other line. Substitution of chromosome pairs 5B or 5D between the parent cultivars Rescue and Cadet substantially altered the amount of root cortex death, which is thus genetically determined. It is suggested thatCochliobolus sativus and other weak parasites benefit from early natural senescence of the root cortex, and that the degree of susceptibility or resistance of wheat lines to common root rot is at least partly determined by differences in cortical senescence.
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  • 65
    ISSN: 1573-5036
    Keywords: Gaeumannomyces graminis ; Hydroponics ; Ion uptake ; Radionuclides ; Root pathogens ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Triple-labelled nutrient solution was used to compare the effects of seven root-infecting fungi on uptake of K, Ca and P by wheat. Plants grown in sand or hydroponic culture were transferred to solutions that contained42K,45Ca and32P for 24 h, then dried, ashed and digested in 6M HCl. To distinguish radiation emitted by42K,45Ca and32P plant digests were counted on two channels of a liquid scintillation counter immediately and 7 days later, after the decay of42K radiation. Plants infected byGaeumannomyces graminis took up and translocated less K, Ca and P to their shoots than uninfected plants. Other root-infecting fungi had little effect on uptake of these ions.
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  • 66
    ISSN: 1573-5036
    Keywords: Aeration ; Calcium ; Carbon dioxide ; Ethylene ; Nitrate ; Nitrite ; Nitrous oxide ; Oxygen ; Potassium ; Roots ; Triticum aestivum ; Waterlogging ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We report a study of the mechanism by which the response of plants to waterlogging can be modified by soil temperature. Wheat was grown initially in well-aerated soil in a controlled environment room before the soil was flooded with aerated, deionized water. The soil temperature was maintained constant in the range 6–18°C while the air temperature was at 14°C. Waterlogging damage was greater in plants at the higher soil temperatures when the plants were compared at the same chronological age. However, when compared at the same growth stage, the response to soil temperature was little differenti.e. plants subjected to waterlogging for a long time at low soil temperatures exhibited a similar reduction in growth and other properties as those subjected briefly at higher temperatures. The concentration of dissolved oxygen in the soil solution declined rapidly at all temperatures, being almost zero after 36 h waterlogging. Temperature affected rates of change of the concentrations of dissolved carbon dioxide, ethylene, nitrous oxide, nitrite, nitrate, calcium and potassium. The importance of soil-and plant-determined properties in the waterlogging response of plants at different temperatures are discussed.
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  • 67
    ISSN: 1573-5036
    Keywords: Barley ; Gaeumannomyces graminis ; Nuclear staining ; Pseudocercosporella herpotrichoides ; Root rot ; Senescence ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nuclear and cytoplasmic staining methods were used to study natural senescence of the root cortex and coleoptile of wheat and barley seedlings grown in glasshouse conditions. Coleoptiles of barley senesced more slowly than those of wheat, paralleling the known difference in rates of root cortex senescence in these cereals. The coleoptiles and root cortices of both cereals senesced more slowly in shaded than in unshaded conditions, but infection of the shoots of barley byErysiphe graminis had little effect on root cortex senescence. The results are discussed in relation to infection by root- and foot-rot fungi. Previous reports on the effects of illumination on take-all infection (Gaeumannomyces graminis) are explained. It is suggested that natural senescence of the coleoptile might affect establishment of infection by the eyespot fungus,Pseudocercosporella herpotrichoides, either directly or through the activities of competing microorganisms.
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  • 68
    ISSN: 1573-5036
    Keywords: 14C-labelled plant material ; 14C-labelled soil ; Root exudation ; Sample oxidizer ; Scintillation counting ; Sutton series soil ; Tissue solubilization ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A comparison between a tissue solubilization method and a sample oxidizer technique to measure14C in plant and soil material is described. The solubilization method although not quantitative gives good recoveries and reproducible values of14C-content with soil samples not exceeding 10 mg and should be of value for estimating the14C-content of soils in laboratories without a sample oxidizer.
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  • 69
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    Plant and soil 77 (1984), S. 141-149 
    ISSN: 1573-5036
    Keywords: Cracks ; Crack width ; Lateral roots ; Pea ; Penetration ; Penetrometer ; Rape ; Remoulded soil ; Roots ; Safflower ; Seminal axes ; Soil strength ; Undisturbed soil ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Experimental methods are described for observing the behaviour of roots encountering cracks in soil. The proportions of roots which enter a second soil block after crossing a crack of known width were measured. Soil strength was measured with a penetrometer. Results are presented for the proportions of seminal roots of wheat and primary lateral roots of pea which enter moulded soil of various strengths after crossing cracks. Results are also presented for the proportions of seminal roots of pea, rape and safflower which enter undisturbed soil after crossing cracks. It was found that, in all cases, the proportion of roots penetrating the second soil block decreased with increasing crack width and increasing soil strength. Also, a smaller proportion of thinner roots penetrated the second soil block than thicker roots under similar conditions. Root diameter in the cracks was influenced by both crack width and soil strength, and an empirical equation is presented to describe this effect.
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  • 70
    ISSN: 1573-5036
    Keywords: Mg/Ca ratio ; Water quality ; Nutrient content ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A study conducted in pots to evaluate the effect of different Mg/Ca ratios (2, 4, 8 and 16) and electrolyte concentrations (20 and 80 meq/l) at SAR 10 in irrigation water on the nutrient uptake and yield of wheat crop in two soils revealed that the average grain and dry matter yields of wheat decreased significantly with an increase in Mg/Ca ratio in irrigation water, but the magnitude of decrease was greater at higher electrolyte concentration than at lower electrolyte concentration. The concentration of Na in both straw and grain of wheat increased and that of K decreased with an increase in Mg/Ca ratio and electrolyte concentration of irrigation water, which led to higher Na/Ca and Na/K ratios in the plant. Further, the concentration of Ca and Mg both in straw as well as in grain increased with increasing electrolyte concentration of the irrigation water. An increasing proportion of Mg in saline irrigation water resulted in decreased concentration of Ca and increased concentration of Mg in both straw and grain of wheat crop. It was also noticed that the increasing proportion of Mg over Ca in the poor quality irrigation water increased the P content of both straw and grain of wheat crop.
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  • 71
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    Plant and soil 65 (1982), S. 433-436 
    ISSN: 1573-5036
    Keywords: Copper-nutrition ; Nitrogen ; Phosphorus ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In a pot culture study, copper addition to soil increased the crop yield only in presence of nitrogen. The latter increased the utilization of both native as well as applied copper but more that of applied. It also minimised the adverse effect of applied phosphorus on copper utilization. Phosphorus at the rate 45 ppm had the tendency of decreasing copper uptake by wheat if applied without nitrogen or with its low level.
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    Plant and soil 68 (1982), S. 69-74 
    ISSN: 1573-5036
    Keywords: Azotobacter ; chroococeum ; Derxia ; gumnosa ; Klebsiella ; Nitrogen ; fixation ; Phyllosphere ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Five highly active N2-fixing strains of Klebsiella isolated from the phyllosphere of tropical plants, KUPBR1, KUPBR2, KUPM, KUP4 and KUP6 along withAzotobacter vinelandii OP,A. chroococcum G40 andDerxia gumnosa were sprayed on the foliage of a high yielding wheat cultivar, Kalyansona. The strains of Klebsiella enhanced dry wt., chrorophyll and nitrogen content, and 1000 grain weight. Grain yield in inoculated plants varied between 19.9 and 25.09 quintals ha−1 against 24.34 quintals with urea. Best results were obtained with KUP4 which when applied at half dose was as effective as 52.5 kg Urea-N ha−1. Azotobacter and Derxia only slightly improved growth and nitrogen content of grain or straw.
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  • 73
    ISSN: 1573-5036
    Keywords: Ammonium acetate extractable potassium ; Inceptisol soil ; Minimum level ; Non-exchangeable potassium ; Pearl millet ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ammonium acetate extractable potassium in the soil reached a minimum value of 6.8 mg K/100g soil after 14 crops of wheat and pearl millet in the field without applying any potassium fertilizer. At this level of ammonium acetate extractable K both wheat and pearl millet utilized about, 90 per cent of the total K from non-exchangeable sources. Wheat and pearl millet were grown in this soil in the greenhouse at different levels of K. At K0 level wheat utilized 86 per cent of the total K uptake from the non-exchangeable source and pearl millet, 95 per cent. At K1 level, wheat utilized only 19 per cent but at higher levels of K, there was build up in the K status of soils. In the case of pearl millet at K1, K2 and K3 levels 59, 13 and 22 per cent of total uptake were contributed by non-exchangeable forms. The total K uptake by pearl millet was more than double that by wheat. Plant analysis showed that 83 per cent of the total K in wheat was contained in the shoot portion and the rest in the roots. The corresponding figures for pearl millet were 94 and 6 per cent.
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  • 74
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    Plant and soil 79 (1984), S. 249-254 
    ISSN: 1573-5036
    Keywords: Acid KMnO4 extraction ; Chemical index ; Incubation ; Mineralizable N ; Mineral N ; N uptake ; Soil ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A chemical measure of soil nitrogen (N) availability has been evaluated. The method involved the estimation of initial mineral N, plus mineralizable N released with 0.05N KMnO4 in 1NH2SO4. The results obtained correlated highly significantly with the N uptake by wheat plants (r=0.72,P〈0.01).
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  • 75
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    Plant and soil 65 (1982), S. 375-382 
    ISSN: 1573-5036
    Keywords: Activity ratio ; Free energy ; Pearl millet ; Potassium supplying capacity ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil samples from a long term field experiment, to study the K depletion pattern, were analysed for K. The values of supply parameters pK−1/2p (Ca+Mg) and free energy δG r 0 were calculated using the data on water soluble and exchangeable cations. Correlation coefficient values between pK−1/2p (Ca+Mg) vs. total K removed, K removal by pearl millet in 1980 and soil available potassium were positive and statistically significant. This indicated that these soils have reached the stage where they would start responding to potassium application. Also, negative but significant correlation of δG r 0 with pK−1/2p (Ca+Mg) and available K, were found. δG r 0 values were positive indicating the affinity of such soils for K and the values, for K fertilized plots were lower in comparison to plots where no K was applied. pK−1/2p (Ca+Mg) parameter was found to be a better measure of K availability over δG r 0 due to either fixation of K or greater contribution of nonexchangeable K fraction towards plant utilized K.
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  • 76
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    Plant and soil 66 (1982), S. 233-241 
    ISSN: 1573-5036
    Keywords: Barley ; Chloride ; Phosphorus ; Salinity ; Sulphate ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The study was conducted in a greenhouse and under field conditions. In the greenoouse, barley was grown to maturity in pots on a sandy soil which contained 80 and 120 meq/l of chloride and sulphate dominant salts in its saturation extract, to which 0, 10, 25 and 50 ppm P were added. In the field study, wheat was grown on loamy sand soils having 0, 25, 50 and 75 kg/ha added P levels and irrigated with either Cl- or SO4-dominant saline waters (EC=15−19 mmhos/cm). The results of the greenhouse study indicated that at maturity barley straw and grain yield was significantly increased by 50 ppm of added P both on the non-saline control and the Cl-treatments. However, 25 ppm P was optimal on the SO4-treatments. The Cl content of plants was significantly decreased and S was increased with the increase in the P content of soil. A synergistic relation between the S and P content of barley shoots was observed. In the field study wheat grain yield responded significantly to P applications upto 50 kg/ha level on the Cl-site and there was no response to applied P on the SO4-site, although the former contained more Olsen's P than the latter. The results suggested that P requirement of wheat and barley was greater on Cl- than on SO4-salinity.
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  • 77
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    Plant and soil 66 (1982), S. 433-437 
    ISSN: 1573-5036
    Keywords: Kaolin spray ; Mulch ; N-application ; Split application ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies revealed that the application of fertilizer nitrogen brought a significant increase in grain and straw yield of wheat. The significant effect was also noticed on such yield contributing characters like number of effective tillers per metre row length, spike length, and number of grains per spike. The increase of nitrogen level from 40 kg/ha to 80 kg/ha also brought a significant increase in yield and yield contributing characters. The application of entire dose of nitrogen at the time of sowing was as good as its split application. The application of nitrogen also influenced the nitrogen concentration of grains whereas, the other treatments did not influence the nitrogen concentration in grains or straw. The nitrogen treatments did not influence the moisture content of soil. The application of mulch or mulch+Kaolin resulted in significantly higher content of soil moisture in 0–15 cm soil depth as compared to control or Kaolin spray alone which was simultaneously reflected in yield and yield contributing characters.
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  • 78
    ISSN: 1573-5036
    Keywords: Calcareous soil ; Chloride ; Dry matter ; Nitrogen ; Phosphate ; Soil salinity ; Triticale ; Triticum aestivum L. ; Water stress ; Wheat ; X Triticosecale Wittmack
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S1=3.5, S2=6, S3=8.5, and S4=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W1), 40% (W2) and 20% (W3) of the available water. The vegetative growth, nitrogen and phosphate were affected by S and W treatments, chloride was affected only by S. The interaction S×W affected only dry weight. Varietal effect was observed between wheat as a group and triticale. Multiple quadratic regression equations of these properties on salinity and water revealed that the higher the available water the wider the range of tolerable salinity. Triticale was relatively more tolerant to water stress. Salinity increases Cl and decreases N, whereas water stress enhances N accumulation to a certain extent. However, in triticale at S3 and S4 the effect of water stress on N was overshadowed by the excessive salinity. This did not occur for the wheat (Florence). P trends were described. R2 for P was low (0.7435–0.3603) which made interpretations rather difficult.
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  • 79
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    Plant and soil 68 (1982), S. 139-141 
    ISSN: 1573-5036
    Keywords: Humic acids ; Silica ; Triticum aestivum L. ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The weathering of soil minerals by humic acids is linked with increased silica content of wheat plants.
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  • 80
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    Plant and soil 76 (1984), S. 379-387 
    ISSN: 1573-5036
    Keywords: Actinomycetes ; Bacteria ; Chernozemic soil ; Fungi ; Rhizosphere ; Trifluralin herbicide ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This study examined the effects of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), a soil incorporated herbicide, on soil microflora both in the general soil environment and in the rhizosphere of trifluralin damaged wheat roots. Two Dark Brown Chernozemic soils were treated with various trifluralin rates in the growth chamber and wheat [Triticum aestivum L. ‘Neepawa’] was seeded. Trifluralin generally had no effect on fungi, bacteria, or actinomycete populations in either the general soil or in the rhizosphere. CO2 evolution was unchanged when trifluralin was added to the soil. In wheat plots, at two field locations, there were no significant effects of trifluralin (1.0 kg ha−1) on soil fungi, bacteria, actinomycete, denitrifying bacteria, and nitrifying Nitrobacter propulations. A pure culture study with 42 soil microorganisms showed that many isolates were inhibited at 400 to 100,000 μg g−1 but not at concentrations 〈16 μg g−1. Similar data were obtained from tests on four different soils. These studies indicate that trifluralin is unlikely to cause changes in the numbers of soil microorganisms when used at recommended levels.
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  • 81
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    Plant and soil 78 (1984), S. 417-428 
    ISSN: 1573-5036
    Keywords: Aphelenchoides spp ; Aphelenchus avenae ; Pinus radiata ; Soil fungi ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The soils of a wheat-field and pine-forest had different mycofloras and supported different populations ofAphelenchus avenae, a mycophagous nematode. The abundance ofA. avenae was correlated with the composition of the mycoflora in these soils; the greater abundance ofA. avenae in wheat-field soil being associated with a more diverse mycoflora.
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  • 82
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    Plant and soil 79 (1984), S. 11-28 
    ISSN: 1573-5036
    Keywords: Beta distribution ; Buckling ; Cracks ; Crack width ; Lateral roots ; Pea ; Penetration ; Penetrometer ; Rape ; Remoulded soil ; Roots ; Safflower ; Seminal axes ; Soil strength ; Undisturbed soil ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary It is shown that probabilities of root penetration across cracks in soil can be calculated effectively using a mathematical model involving root stress and soil distributions and penetrometer/root stress ratios. Penetration criteria are developed, and it is found that the effective penetrometer/root stress ratios take values of about 4 for crack widths smaller than about 2 mm and about 8 for wider cracks. Root swelling does not appear to contribute significantly to the probability of root penetration through any effect on root buckling stress. Suggestions are made for further work on the effects of soil structure and strength on root behaviour.
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  • 83
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    Nutrient cycling in agroecosystems 5 (1984), S. 285-288 
    ISSN: 1573-0867
    Keywords: Wheat ; potassium chloride ; irrigation ; plant water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract ‘The water potential of wheat plants increased during the mid-day noon, probably as an adaptation; the rise was greater with less frequent irrigation and was increased by KCl application.’
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  • 84
    ISSN: 1573-5060
    Keywords: Wheat ; Triticum aestivum ; wheat breeding ; selection ; grain yield ; harvest index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Aspects of selection for yield and harvest index were investigated by simulating selection using data from random pedigreed F2, F3, F4 and F5 derived lines from two crosses grown in plots at two sites over two years. Improvement in yield through selection was obtained when the response was measured at the same site and in the same year as the selection. Selecting the best 10 per cent of F2 to F4 derived lines gave F5 derived lines that outyielded random selections by 19 to 53 per cent for one cross and 5 to 23 per cent for the second cross. These lines were 41 to 50 per cent better than the mid-parent in one cross, but were less than the mid-parent in the other cross. However, the response to selection when measured in a different year was little better than random selection. The effect of different sites also reduced the effectiveness of selection. Selection of harvest index in early generations for improvement of yield was ineffective when response was measured at the same site in the same year, or in different years. Contrary to some theoretical proposals, the same improvement in yield was obtained by selecting in early or late generations. While high yielding genotypes may be lost by delaying selection, this is counteracted by the better predictive value of late generations due to their greater homozygosity and homogeneity.
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  • 85
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    Plant and soil 80 (1984), S. 135-138 
    ISSN: 1573-5036
    Keywords: Hardpans ; Root growth ; Soil compaction ; Subterranean clover ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Wheat crops with stunted chlorotic patches are widespread in northern Victoria, Australia, and are often associated with dense, compacted layers of soil. Poor growth of subterranean clover, with symptoms of cupped and reddened leaflets, is also a problem in these cropping regions during the pasture phase of the rotation. Artificially compacted soils were created to test the hypothesis that these symptoms of poor growth were caused by soil compaction. Soil compacted from 0–20 cm with a bulk density similar to that measured in problem fields reproduced these symptoms in wheat and subterranean clover. Surface compaction alone also reproduced the symptoms in clover.
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  • 86
    ISSN: 1573-5036
    Keywords: Azospirillum brasilense ; Wheat ; Triticum aestivum ; N-fertilizer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The yield response of a common spring wheat cultivar,Triticum aestivum, to inoculation withAzospirillum brasilense was studied at four levels of N fertilization. Plant yield increased due to the inoculation treatment only at medium and high levels of N fertilization, with a maximum yield increase of about 8.0 per cent at the highest level (approximately 1.0 g of pure N per plant). Yield increase was mostly due to an increase in the number of grains per spike, and at the highest level of fertilization, also due to a higher number of spikes per plant. At all N levels, the inoculation caused an increase of 0.5–1.4 per cent in the number of fertile spikelets per main spike. Grain protein percentage was unaffected by the inoculation, though significantly increase due to the fertilization treatments. The occurrence of maximum yield response at the highest N level, the response by early-determined yield components, i.e. spikelet number, and the unaffected grain protein content are in accord with the suggestion that the contribution ofAzospirillum brasilense to wheat yield is not through N2-fixation.
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  • 87
    ISSN: 1432-0878
    Keywords: Mitochondria ; Meiosis ; Spermiogenesis ; Drosophila ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphogenesis of mitochondria in male germ cells in cultivated cytocysts begins in early prophase I at which time mitochondria thicken and become ordered along the spindle apparatus during meiosis. At the end of the second meiotic division they aggregate to form the Nebenkern. In the presence of colchicine or cytochalasin B mitochondria are able to begin differentiation, although the correct course of meiosis is not guaranteed. In medium supplemented with colchicine they undergo normal thickening but do not aggregate, in a pattern known from untreated cultures. This may indicate that microtubules are involved in the aggregation process of mitochondria as colchicine is known to inhibit microtubule formation. Moreover, in cell cultures treated with cytochalasin B mitochondrial aggregation does occur; it is concluded that microfilaments, which are sensitive to cytochalasin B, do not play a detectable role in the aggregation of mitochondria.
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  • 88
    ISSN: 1432-0878
    Keywords: Transmission and high voltage electron microscopy ; Drosophila ; Degeneration ; Retinular cells ; Optic neuropiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The compound eye and the two most distal optic neuropils (lamina ganglionaris and medulla externa) of the Drosophila mutant w rdgB KS222were examined with transmission electron microscopes at conventional (60 kV) and high (0.8–1 MV) voltages. Eye tissue was sampled in the newly emerged and at 3, 7, and 21 days following eclosion. This mutant is known to show a light-induced degeneration of the peripheral retinular cells (R 1–6); the spectral sensitivity is altered and the threshold is increased reflecting the function of the central cells (R7, 8) which do not degenerate. A totally normal appearing visual system (peripheral retina and optic neuropiles) was found in newly emerged adults. After 3 days the somata of some of the peripheral retinal cells are affected and all of their axons show degeneration. At one week the R 1–6 pathology is well advanced in both somal and axonal regions. In affected cells the cytoplasm is more or less uniformly electron dense and contains liposomes, lysosome-like bodies, myeloid figures and vacuoles suggesting autophagy. Such cytoplasm (noted at 3 and 7 days post-eclosion) exhibits an electron dense reticulum and degenerate mitochondria. Microvilli become more electron dense. Retinular axon terminals are electron opaque and lack synaptic vesicles with few if any presynaptic structures. Mitochondrial remains are barely recognizable. Transsynaptic degeneration was not found. After 3 weeks, the structure of R 1–6 in the peripheral retina (somata and rhabdomeres) is greatly reduced or lost while R7 and R8 and higher order neurons are not affected. The debris from cell bodies and axon terminals of R 1–6 seems diminished, so that some phagocytosis probably takes place along with gliosis in the lamina.
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  • 89
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    Cell & tissue research 221 (1982), S. 607-615 
    ISSN: 1432-0878
    Keywords: Hemocytes ; Drosophila ; Ultrastructure ; Phagocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hemocytes of Drosophila melanogaster and Drosophila yakuba larvae have been defined in terms of their ultrastructure and functions in “coagulation”, wound healing, encapsulation, phenol-oxydase activity, and phagocytosis. The position of these cells among the classical hemocyte types of insects is determined. We distinguish two plasmatocyte types (macrophage plasmatocytes and lamellocytes) which do not seem to belong to the same lineage, and oenocytoids which are the crystal cells of the literature.
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  • 90
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    Cell & tissue research 224 (1982), S. 315-333 
    ISSN: 1432-0878
    Keywords: Oogenesis ; Vitellogenesis ; Radiolabelling ; Metabolism ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative light- and electron-microscopic autoradiography was used to evaluate metabolic processes that occur during late developmental stages (10–14) of oogenesis in Drosophila melanogaster. Major differences in radiolabelling patterns were found after in vivo (10–45 min) uptake of [3H]-monosaccharides and [3H]-L-lysine. Several different methods of data analysis were required to facilitate interpretation of these patterns. [3H]-L-lysine produced extensive cytoplasmic labelling at all developmental stages. In addition, about 15% of alpha yolk spheres were intensely labelled at stage 10, reflecting the incorporation of radiolabelled vitellogenins synthesized during the incubation period. Subsequent stages showed low silver grain density over alpha yolk spheres until stage 14, when a burst of [3H]-L-lysine incorporation by most alpha spheres was observed, possibly indicative of a maturation process for embryogenesis. [3H]-D-glucose and [3H]-D-galactose (10 min, in vivo) both induced intense labelling of the beta yolk spheres in a manner suggesting in situ assembly beginning at early stage 13. Inasmuch as the polysaccharide of beta yolk spheres has the properties of glycogen (e.g., rosette structure digested by α-amylase) and the radiolabelled monosaccharides were introduced intraabdominally, it is evident that transport systems as well as enzymes utilizing glucose and galactose for glycogenesis must be readily available. It is notable that wide-spread labelling of egg chambers was elicited by [3H]-D-glucose and [3H]-D-galactose (e.g., nurse cells, follicle cells, chorion, vitelline membrane), but the labelling induced by [3H]-N-acetylmannosamine was restricted mainly to the endochorion. A possible role of microtubules in distribution and assembly of yolk spheres was inferred when colchicine, admixed to the culture medium (2–5 ppm), produced abnormal distribution and diminution in number of both alpha and beta yolk spheres. In addition to revealing previously unknown metabolic events of vitellogenesis, the results provide additional criteria for stage characterization as well as a means to specifically label certain macromolecules for purposes of isolation.
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