排序方式: 共有86条查询结果,搜索用时 9 毫秒
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Zheng Liu Joe Hammerlindl Wilf Keller Peter B. E. McVetty Fouad Daayf Carlos F. Quiros Genyi Li 《Molecular breeding : new strategies in plant improvement》2011,27(4):467-478
Methylthioalkylmalate (MAM) synthases and their associated genes that have been extensively investigated in Arabidopsis control the side-chain elongation of methionine during the synthesis of aliphatic glucosinolates. A Brassica homolog of the Arabidopsis
MAM genes was used in this study to analyze the role of MAM genes in B. napus through RNA interference (RNAi). The silencing of the MAM gene family in B. napus canola and B. napus rapeseed resulted in the reduction of aliphatic glucosinolates and total glucosinolate content. The results indicated that
RNAi has potential for reducing glucosinolate content and improving meal quality in B. napus canola and rapeseed cultivars. Interestingly, MAM gene silencing in B. napus significantly induced the production of 2-propenyl glucosinolate, a 3-carbon side-chain glucosinolate commonly found in B. juncea mustard. Most transgenic plants displayed induction of 2-propenyl glucosinolate; however, the absolute content of this glucosinolate
in transgenic B. napus canola was relatively low (less than 1.00 μmol g−1 seed). In the high glucosinolate content progenies derived from the crosses of B. napus rapeseed and transgenic B. napus canola, MAM gene silencing strongly induced the production of 2-propenyl glucosinolate to high levels (up to 4.45 μmol g−1 seed). 相似文献
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Wilf E 《American anthropologist》2012,114(1):32-44
In this article, I seek to complicate the distinction between imitation and creativity, which has played a dominant role in the modern imaginary and anthropological theory. I focus on a U.S. collegiate jazz music program, in which jazz educators use advanced sound technologies to reestablish immersive interaction with the sounds of past jazz masters against the backdrop of the disappearance of performance venues for jazz. I analyze a key pedagogical practice in the course of which students produce precise replications of the recorded improvisations of past jazz masters and then play them in synchrony with the recordings. Through such synchronous iconization, students inhabit and reenact the creativity epitomized by these recordings. I argue that such a practice, which I call a “ritual of creativity,” suggests a coconstitutive relationship between imitation and creativity, which has intensified under modernity because of the availability of new technologies of digital reproduction. 相似文献
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Wilf P Johnson KR Cúneo NR Smith ME Singer BS Gandolfo MA 《The American naturalist》2005,165(6):634-650
The origins of South America's exceptional plant diversity are poorly known from the fossil record. We report on unbiased quantitative collections of fossil floras from Laguna del Hunco (LH) and Río Pichileufú (RP) in Patagonia, Argentina. These sites represent a frost-free humid biome in South American middle latitudes of the globally warm Eocene. At LH, from 4,303 identified specimens, we recognize 186 species of plant organs and 152 species of leaves. Adjusted for sample size, the LH flora is more diverse than comparable Eocene floras known from other continents. The RP flora shares several taxa with LH and appears to be as rich, although sampling is preliminary. The two floras were previously considered coeval. However, (40)Ar/(39)Ar dating of three ash-fall tuff beds in close stratigraphic association with the RP flora indicates an age of 47.46+/-0.05 Ma, 4.5 million years younger than LH, for which one tuff is reanalyzed here as 51.91+/-0.22 Ma. Thus, diverse floral associations in Patagonia evolved by the Eocene, possibly in response to global warming, and were persistent and areally extensive. This suggests extraordinary richness at low latitudes via the latitudinal diversity gradient, corroborated by published palynological data from the Eocene of Colombia. 相似文献
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Yongjun Du Guy M. Poppy Wilf Powell Lester J. Wadhams 《Journal of Insect Behavior》1997,10(4):509-522
The effect of experience on the responsiveness of the braconid parasitoidAphidius ervi to host(Acyrthosiphon pisum)-associated cues was investigated on bean plants(Vicia faba) using a wind tunnel bioassay. Oviposition experience on the plant-host complex significantly increased the oriented flight
and landing responses ofA. ervi females to an undamaged plant and to a plant-host(A. pisum) complex. However, oviposition experience onA. pisum aphids when isolated from the plant did not change their responses to the intact plant and the complex. Searching on an unwashed
plant which had been previously damaged byA. pisum also increased their response to an undamaged plant and a host-damaged plant, whereas the experience of searching on an undamaged
plant did not significantly change their responses to undamaged plants. However, when parasitoids were allowed to search on
an undamaged plant which had been sprayed withA. pisum honeydew, this significantly increased their response to an undamaged plant. Oviposition experience on the plant-host complex
and foraging experience on a host-damaged plant or an undamaged plant sprayed with honeydew also significantly reduced the
mean time taken by the parasitoids to respond in the wind tunnel. The behavioral changes associated with such experience were
acquired within 30 min and persisted for at least 3 days. The results demonstrate the capacity ofA. ervi to learn associatively olfactory cues from plants, host-damaged plants, and plant-host complexes and confirm the role of
aphid honeydew as a host recognition kairomone forA. ervi. 相似文献
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The Southeast Asian rainforest region is extremely complex and biodiverse. Fossils have shown that paleo-Antarctic rainforest lineages (PARLs) now extant in Asia tracked the ever-wet conditions needed to survive and diversify through deep time. However, the threat of future climate change to the remaining rainforest and PARLs in Southeast Asia has yet to be evaluated to set conservation priorities. We first quantified the woody-genus floristic relationships of Southeast Asian Island Groups by vetting and analyzing recent compilations of bioregional species data. We then evaluated the contributions to community assembly of woody fossil lineages and Island Group relationships to environmental gradients. To better understand climatic constraints of fossil lineage distributions and forecast distributions under projected future climate, we used exemplar living woody PARLs, including two angiosperms and two gymnosperms. Generalized linear models were used to project potential distributions under future climate pathways that assume no reduction in carbon dioxide emissions. The floristic analyses highlighted strong similarities among Island Groups in the ever-wet forest areas of Malesia, where PARLs are often concentrated. Ordination outliers represented more seasonal locations. Species distribution models showed that potential future distributions of ancient lineages are constrained by increasing rainfall seasonality and higher seasonal temperatures, with significant differences among exemplar genera. Notably, potential distributions often mapped onto de facto inaccessible areas, where forest clearing and the ubiquitous marine dispersal barriers that characterize the region will drastically inhibit potential relocation. These realities gravely threaten paleo-conservation values and contemporary rainforest community assembly processes in Southeast Asia. 相似文献
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Benefits of rebuilding global marine fisheries outweigh costs 总被引:1,自引:0,他引:1
UR Sumaila W Cheung A Dyck K Gueye L Huang V Lam D Pauly T Srinivasan W Swartz R Watson D Zeller 《PloS one》2012,7(7):e40542
Global marine fisheries are currently underperforming, largely due to overfishing. An analysis of global databases finds that resource rent net of subsidies from rebuilt world fisheries could increase from the current negative US$13 billion to positive US$54 billion per year, resulting in a net gain of US$600 to US$1,400 billion in present value over fifty years after rebuilding. To realize this gain, governments need to implement a rebuilding program at a cost of about US$203 (US$130-US$292) billion in present value. We estimate that it would take just 12 years after rebuilding begins for the benefits to surpass the cost. Even without accounting for the potential boost to recreational fisheries, and ignoring ancillary and non-market values that would likely increase, the potential benefits of rebuilding global fisheries far outweigh the costs. 相似文献