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51.
Teen‐Lee Pua Tian‐Tian Tan Nurzatil S. M. Jalaluddin Rofina Y. Othman Jennifer A. Harikrishna 《The Annals of applied biology》2019,175(3):282-301
Since the first two successful transformation events in banana were reported in 1995, considerable effort has been invested to develop new cultivars with improved tolerance to biotic and abiotic stresses and with enhanced nutrient levels, primarily using Agrobacterium‐mediated transformation and particle bombardment. In addition to many promising laboratory‐based studies, several genetically engineered banana cultivars have been trialled in the field. However, the deployment of genetically engineered varieties of bananas lags behind that of other major crops and there has been no commercial plantation. This article provides a review of advances in the genetic engineering of banana with an overview of noteworthy developments in several programmes that are being conducted worldwide. We identify the main challenges to translating the full potential of genetically engineered bananas for human consumption as the intellectual property issues surrounding the technology, public perceptions towards the adoption of the transformed bananas as well as various regulatory hurdles that hold the technology development from moving forward. 相似文献
52.
53.
Eng-Chong Pua Elena Ragolsky Stephen F. Chandler Trevor A. Thorpe 《Plant Cell, Tissue and Organ Culture》1985,5(1):55-62
Callus of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) was grown on callus-proliferating (CP) and shoot-forming (SF) media with elevated sodium sulfate (Na2SO4) concentrations either in the light or dark for more than one year. An increase in Na2SO4 concentration resulted in a decrease in callus growth index, an increase in percent dry weight of callus tissues grown on both media, and a decrease in both number of calli forming shoots and number of shoots per callus in SF medium. The CP callus grown in the light spontaneously began to form shoots after the 5th monthly transfer, and spontaneous root formation occured after the 16th transfer in the presence of 0.75 and 1.0% Na2SO4. Both water () and osmotic (s) potentials of the callus increased with increasing Na2SO4 concentration; and callus exhibited greater and s in the light than dark for both CP and SF media. 相似文献
54.
Phytoliths (silica bodies) occur in Poaceae species in large numbers and have been shown to have antiherbivory roles. However, phytoliths occur also in many other taxa in much smaller numbers, which raises the question of the extent of both their potential and actual antiherbivory role in these taxa. In order to address the question of their potential antiherbivory role, we sampled 20 wild-growing southwest Asian species of the family Asteraceae, species of which have a much lower phytolith concentrations than Poaceae taxa. We studied the potential positive effect of grazing on phytolith formation and the possible tendency of plants to have higher concentrations of such defence structures in their reproductive organs. We sampled plants from populations of 12 non-spiny and eight spiny species growing in un-grazed and grazed plots in seven sites along a large rainfall gradient (80–900 mm mean annual) in Israel, a region known for its long and intensive grazing history. The study included 21 pairs of un-grazed and grazed plants from 16 of these 20 species. In addition, ten populations of eight species were sampled in order to examine whether phytolith concentrations in the reproductive organs are higher than in vegetative organs. We did not find consistently higher phytolith concentrations in grazed plants compared to un-grazed plants of the same species and habitat (15 species), and in 12 out of 21 pairs of un-grazed and grazed plants (from 15 species) we even found higher phytolith concentrations in un-grazed plants, a phenomenon which was more common in the more arid sites. Phytolith concentrations in inflorescences are commonly (6 out of the 8 species) lower than in the rest of the shoot. We conclude that the antiherbivory potential of phytoliths in the southwest Asian Asteraceae as a group is much smaller than in the Poaceae. 相似文献
55.
Role of Ethylene on de Novo Shoot Regeneration from Cotyledonary Explants of Brassica campestris ssp. pekinensis (Lour) Olsson in Vitro 总被引:3,自引:2,他引:3 下载免费PDF全文
The promotive effect of AgNO3 and aminoethoxyvinylglycine (AVG) on in vitro shoot regeneration from cotyledons of Brassica campestris ssp. pekinensis in relation to endogenous 1-amino-cyclopropane-1-carboxylic acid (ACC) synthase, ACC, and ethylene production was investigated. AgNO3 enhanced ACC synthase activity and ACC accumulation, which reached a maximum after 3 to 7 days of culture. ACC accumulation was concomitant with increased emanation of ethylene which peaked after 14 days. In contrast, AVG was inhibitory to endogenous ACC synthase activity and reduced ACC and ethylene production. The promotive effect of AVG on shoot regeneration was reversed by 2-chloroethylphosphonic acid at 50 micromolar or higher concentrations, whereas explants grown on AgNO3 medium were less affected by 2-chloroethylphosphonic acid. The distinctive effect of AgNO3 and AVG on endogenous ACC synthase, ACC, and ethylene production and its possible mechanisms are discussed. 相似文献
56.
Christopher J. Walsh Phil J. Papas Diane Crowther Pua Tai Sim Jaeyong Yoo 《Biodiversity and Conservation》2004,13(4):781-793
The general hypothesis that catchment urbanization explained the distribution of the threatened, stream-dwelling amphipod Austrogammarus australis (listed under the Victorian Flora and Fauna Guarantee Act 1988) was tested using several surveys of 58 sites in streams draining the Dandenong Ranges on the eastern fringe of Melbourne, Victoria, Australia. More specifically, four catchment-scale elements of urban land, hypothesized as sources of stress to receiving streams, were separated: catchment imperviousness, drainage connection (proportion of impervious areas connected to streams by stormwater pipes), density of unsealed roads and density of septic tanks. The degree to which each attribute independently and jointly explained the occurrence of A. australis was assessed using hierarchical partitioning of logistic regression analyses. Drainage connection independently best explained the occurrence of A. australis, pointing to stormwater drainage design as the priority area of catchment management for the conservation of the species. The separation of urban land use into attributes that characterize likely stressor sources provides a useful framework for assessing and prioritizing the most appropriate management actions to minimize urban-related stresses to aquatic biota. 相似文献
57.
First identified as a pathway for nutrient recovery during periods of starvation, the role of autophagy has expanded to the clearance of "toxic" intracellular material including ubiquitin-positive protein aggregates, damaged organelles as well as microbial pathogens in various cell types. We have examined the role of autophagy in the development and function of the adaptive immune system. Genes encoding autophagy machinery are expressed in T lymphocytes, and autophagy occurs in primary CD4+ and CD8+ T cells. By generating fetal liver chimeric mice, we found that thymocyte development is largely normal but the mature T cell compartment is severely reduced in the absence of the essential autophagy gene Atg5. Consistent with a critical role for autophagy in promoting T cell survival, Atg5-/- CD8+ T cells display high levels of apoptosis. Surprisingly, Atg5-deficient T cells were also unable to efficiently proliferate after T-cell receptor (TCR) stimulation. These findings suggest that autophagy regulates T lymphocyte homeostasis by promoting both survival and proliferation. In addition, T cells offer a new, physiologically relevant system to study the regulation and function of autophagy pathways in vivo. 相似文献
58.
Summary The promotive effect of ethylene inhibitors (Els), i.e. AgNO3 and aminoethoxyvinylglycine (AVG) on de novo shoot regeneration from cultured cotyledonary explants of Brassica campestris ssp. pekinensis cv. Shantung in relation to polyamines (PAs) was investigated. The endogenous levels of free putrescine and spermidine in the explant decreased sharply after 1–3 days of culture, whereas endogenous spermine increased, irrespective of the absence or presence of Els. AgNO3 at 30 M did not affect endogenous PAs during two weeks of culture. In contrast, explants grown on medium containing 5 M AVG produced higher levels of free putrescine and spermine which increased rapidly after three days and reached a peak at 10 days. An exogenous application of 5 mM putrescine also resulted in a similar surge of endogenous free spermine of the explant. More strikingly, shoot regeneration from explants grown in the presence of 1–20 mM putrescine, 0.1–2.5 mM spermidine, or 0.1–1 mM spermine was enhanced after three weeks of culture. However, exogenous PAs generally did not affect ethylene production, and endogenous levels of 1-aminocyclopropane-1-carboxylate (ACC) synthase activity and ACC of the explant. This study shows the PA requirement for shoot regeneration from cotyledons of B. campestris ssp. pekinensis in vitro, and also indicates that the promotive effect of PAs on regeneration may not be due to an inhibition of ethylene biosynthesis.Abbreviations PAs
polyamines
- AVG
aminoethoxyvinylglycine
- SAM
S-adenosylmethionine
- ACC
1-aminocyclopropane-1-carboxylate
- Els
ethylene inhibitors 相似文献
59.
地中海沿岸沙丘土壤种子库的异质性 总被引:13,自引:0,他引:13
应用自然萌发法和物理筛选法相结合的方法,调查了地中海沿岸沙丘三种微生境土壤总种子库和永久种子库特征,用功能群的方法分析了微生境之间的土壤总种子库和永久土壤种子库的组成和结构差异,也分析了主要物种土壤种子库的微生境分布格局,分析了种子大小和土壤种子库中的种子永久性关系。发现地中海沿岸沙丘土壤种子库具有明显的空间异质性,即使在相同的微生境内,土壤种子库的分布也不是均匀的,甚至具有很大的差异;微生境对总的土壤种子库和各功能群的土壤种子库的分布格局具有显著的影响,开阔地区域具有最大的种子密度,而灌丛下和路径具有较小的种子密度;在永久土壤种子库中,豆科类植物种子在休眠种子中占有最大的比例,约为76%,而一年生和多年生禾草未发现休眠种子,豆类、伞形科类、多年生阔草、菊科类、一年生阔叶草和十字花科类等种子在土壤中的永久性比例依次下降,分别为50%、46%、41%、6%、6%和1%,微生境影响各功能群种子在土壤中的永久性。微生境显著影响大部分主要物种的土壤种子库分布;种子大小与其在土壤中的永久性为正相关,即大种子具有较高的永久性,小种子具有较低的永久性。 相似文献
60.
Keld Poulsen Justyna MC Bahl Anja H Simonsen Steen G Hasselbalch Niels HH Heegaard 《Clinical proteomics》2014,11(1):12