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排序方式: 共有52条查询结果,搜索用时 31 毫秒
1.
Abstract. 1. The relationship between cyanogenesis in bracken fern and the insect fauna feeding on the plant was investigated over a 3 year period. The most common insects between May and July, while cyanide levels were high, were the sawflies Strongylogaster impressata Provancher, S.multicincta Norton, Aneug-menus fzavipes (Norton), the aphid Macrosiphum euphorbiae (Thomas) and a microlepidopteran species of Monochroa .
2. Collections of insects from cyanogenic and acyanogenic fronds showed significantly fewer sawflies on the cyanogenic fronds. The aphid and the microlepidopteran were randomly distributed with respect to cyanogenicity.
3. Feeding tests for two of the sawfly species ( Simpressata and Smulticincta ) showed that larvae grew more slowly and had a higher mortality when raised on cyanogenic fronds than on acyanogenic ones.
4. Field collected cyanogenic bracken fronds were found to have sustained less damage from chewing herbivores compared with acyanogenic fronds. 相似文献
2. Collections of insects from cyanogenic and acyanogenic fronds showed significantly fewer sawflies on the cyanogenic fronds. The aphid and the microlepidopteran were randomly distributed with respect to cyanogenicity.
3. Feeding tests for two of the sawfly species ( Simpressata and Smulticincta ) showed that larvae grew more slowly and had a higher mortality when raised on cyanogenic fronds than on acyanogenic ones.
4. Field collected cyanogenic bracken fronds were found to have sustained less damage from chewing herbivores compared with acyanogenic fronds. 相似文献
2.
South American leaf blight of the rubber tree (Hevea spp.): new steps in plant domestication using physiological features and molecular markers 总被引:1,自引:0,他引:1
Lieberei R 《Annals of botany》2007,100(6):1125-1142
BACKGROUND: Rubber trees (Hevea spp.) are perennial crops of Amazonian origin that have been spread over the whole tropical belt to guarantee worldwide production of natural rubber. This crop plant has found its place in many national economies of producing countries, and although its domestication by selection of suitable genotypes was very slow, it contributes a lot to the welfare of small farmers worldwide. Its development is limited by severe diseases. In South America, the main fungal disease of rubber trees is the South American leaf blight (SALB) caused by the ascomycete Microcyclus ulei. This fungus inhibits natural rubber production on a commercial scale in South and Central America. SCOPE: The disease is still restricted to its continent of origin, but its potential to be distributed around the world rises with every transcontinental airline connection that directly links tropical regions. The need to develop control measures against the disease is an urgent task and must be carried out on an international scale. All control efforts so far taken since 1910 have ended in a miserable failure. Even the use of modern systemic fungicides and use of greatly improved application techniques have failed to prevent large losses and dieback of trees. The results of research dealing with both the disease and the pathosystem over more than 50 years are summarized and placed into perspective. FUTURE PROSPECTS: A detailed knowledge of this host-pathogen combination requires understanding of the dynamics of Hevea leaf development, the biochemical potential for cyanide liberation, and molecular data for several types of resistance factors. Resolution of the Hevea-SALB problem may serve as a model for future host-pathogen studies of perennial plants requiring a holistic approach. 相似文献
3.
4.
S C Campbell G J Olson T R Clark G McFeters 《Journal of industrial microbiology & biotechnology》2001,26(3):134-139
Chromobacterium violaceum is a cyanogenic (cyanide-producing) microorganism. Cyanide is used on an industrial scale to complex and recover gold from
ores or concentrates of ores bearing the precious metal. A potentially useful approach in gold mining operations could be
to produce cyanide biologically in relatively small quantities at the ore surface. In this study, C. violaceum grown in nutrient broth formed a biofilm and could complex and solubilize 100% of the gold on glass test slides within 4–7
days. Approximately 50% of the cyanide-recoverable gold could be mobilized from a biooxidized sulfidic-ore concentrate. Complexation
of cyanide in solution by gold appeared to have a beneficial effect on cell growth — viable cell counts were nearly two orders
of magnitude greater in the presence of gold-coated slides or biooxidized ore substrates than in their absence. C. violaceum was cyanogenic when grown in alternative feedstocks. When grown in a mineral salt solution supplemented with 13.3% v/v swine
fecal material (SFM), cells exhibited pigmentation and suspended cell concentrations comparable to cultures grown in nutrient
broth. Glycine supplements stimulated production of cyanide in 13.3% v/v SFM. In contrast, glycine was inhibitory when added
at the time of inoculation in the more concentrated SFM, decreasing cell numbers and reducing ultimate bulk-solution cyanide
concentrations. However, aeration and addition of glycine to stationary phase cells grown on 13.3% v/v SFM anaerobically resulted
in rapid production and high concentrations (up to 38 mg l−1) of cyanide. This indicates that biogenesis of cyanide may be supported in remote areas using locally produced and inexpensive
agricultural feedstocks in place of commercial media. Journal of Industrial Microbiology & Biotechnology (2001) 26, 134–139.
Received 06 June 2000/ Accepted in revised form 30 September 2000 相似文献
5.
6.
The recurrent evolution of adaptive clines within a species can be used to elucidate the
selective factors and genetic responses that underlie adaptation. White clover is
polymorphic for cyanogenesis (HCN release with tissue damage), and climate-associated
cyanogenesis clines have evolved throughout the native and introduced species range. This
polymorphism arises through two independently segregating Mendelian polymorphisms for the
presence/absence of two required components: cyanogenic glucosides and their
hydrolyzing enzyme linamarase. Cyanogenesis is commonly thought to function in herbivore
defense; however, the individual cyanogenic components may also serve other physiological
functions. To test whether cyanogenesis clines have evolved in response to the same
selective pressures acting on the same genetic targets, we examined cyanogenesis cline
shape and its environmental correlates in three world regions: southern New Zealand, the
central United States and the US Pacific Northwest. For some regional comparisons, cline
shapes are remarkably similar despite large differences in the spatial scales over which
clines occur (40–1600 km). However, we also find evidence for major
differences in both the agents and targets of selection among the sampled clines.
Variation in cyanogenesis frequency is best predicted using a combination of minimum
winter temperature and aridity variables. Together, our results provide evidence that
recurrent adaptive clines do not necessarily reflect shared adaptive processes. 相似文献
7.
The cyanogenic glycoside, proacacipetalin, is reported from Acacia pachyphloia (Acacia subgenus Acacia). This represents the first record of a glycoside with an aliphatic aglycone from a species of Acacia indigenous to Australia. This finding reinforces the taxonomic distinctions between subgenus Acacia and subgenus Phyllodineae. 相似文献
8.
Identifying the genetic basis of parallel phenotypic evolution provides insight into the process of adaptation and evolutionary constraint. White clover (Trifolium repens) has evolved climate‐associated adaptive clines in cyanogenesis (the ability to produce hydrogen cyanide upon tissue damage) in several world regions where it has been introduced. Gene‐deletion polymorphisms at the CYP79D15 and Li loci underlie the presence/absence of the cyanogenic phenotype. Both loci have undergone multiple independent gene‐deletion events, which are identifiable through molecular signatures in flanking regions. To investigate whether cyanogenesis clines in introduced populations have evolved through the sorting of standing genetic variation or de novo gene deletions, we examined cyanogenesis gene‐flanking regions in three world regions. In comparison with native Eurasian populations, we find no evidence for novel gene deletion events in any introduced region, which suggests that these adaptive clines have evolved through the geographical sorting of pre‐existing genetic variation. 相似文献
9.
Callus and cell suspension cultures were established from root and shoot tips of aseptically-grown seedlings of highly cyanogenic Phaseolus lunatus L. varieties. The content of cyanogenic glucosides in the explanted seedling sections decreased during storage, the derived callus cells were free of cyanogenic glycosides. In spite of the non-existence of cyanogenic glucosides, the cyanogen degrading linamarase, the cyanide detoxifying enzyme -cyanoalanine synthase and also hydroxynitrile lyase were still present in suspension cultures. The linamarase activity equalled the total -glucosidase activity, of which up to 80% was found in the culture medium. In contrast the -cyanoalanine synthase and the hydroxy nitrile lyase were entirely localized in the cell biomass.~Botanical Institute, Technical University Braunschweig 相似文献
10.
Cell suspension cultures of Eschscholtzia californica produce one or more cyanogenic compounds when placed under osmotic stress. The nature of the compound(s) has not yet been established but they are not identical with the cyanogenic glucosides triglochinin and dhurrin, which occur in the intact plant. Microsomal fractions isolated from stressed cell cultures catalyze the synthesis of 1-(4-hydroxyphenyl)-2-nitroethane from L-tyrosine. Both NADPH and molecular oxygen are required as cosubstrates, and 4-hydroxyphenylacetaldoxime is an intermediate in the synthesis of the nitrocompound. This observation indicates that the biosynthetic pathways leading from L-tyrosine to 1-(4-hydroxyphenyl)-2-nitroethane and to the L-tyrosine-derived cyanogenic glucosides are closely related. A glucosyltransferase which glucosylates the nitrocompound in the presence of uridine diphosphate glucose appears in the osmotically stressed cultures in a time pattern similar to that for production of the nitrocompound.Abbreviations HPAA
4-hydroxyphenylacetaldoxime
- HPLC
high-pressure liquid chromatography
- HPNE
1-(4-hydroxyphenyl)-2-nitroethane
- TLC
thin-layer chromatography 相似文献