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61.
This study examined the performances of 21 cassava cultivars in two cropping seasons on the field against root rot disease and the yield in cassava-maize intercrop. Data were collected on number of root/plant, weight of root (t/ha) and disease severity (DS) on rotted roots at 12 and 16 months after planting (MAP), respectively. There were significant (P ≤ 0.05) differences for DS at 12 and 16 MAP in both seasons with cultivar TMS 97/JW2 having the least DS score. TMS 97/JW2 was resistant to the root rot pathogen, while eleven other cultivars were moderately resistant to the disease at 16 MAP. There was no consistency in the roots weight for the cultivars over the two cropping seasons but higher roots weight was recorded at 16 MAP than 12 MAP with different cultivars having highest roots weight at these periods. Intercropping maize with cassava does not have any management potential on root rot development.  相似文献   
62.
The fungal toxin α-amanitin given in vivo selectively inhibits for 10–60 min a nucleoplasmic type of RNA polymerase in rat liver but the synthesis in vivo of all species of nuclear RNA remains blocked for several hours.  相似文献   
63.
In this paper, we use the Rothamsted Carbon Model to estimate how cropland mineral soil carbon stocks are likely to change under future climate, and how agricultural management might influence these stocks in the future. The model was run for croplands occurring on mineral soils in European Russia and the Ukraine, representing 74 Mha of cropland in Russia and 31 Mha in the Ukraine. The model used climate data (1990–2070) from the HadCM3 climate model, forced by four Intergovernmental Panel on Climate Change (IPCC) emission scenarios representing various degrees of globalization and emphasis on economic vs. environmental considerations. Three land use scenarios were examined, business as usual (BAU) management, optimal management (OPT) to maximize profit, and soil sustainability (SUS) in which profit was maximized within the constraint that soil carbon must either remain stable or increase. Our findings suggest that soil organic carbon (SOC) will be lost under all climate scenarios, but less is lost under the climate scenarios where environmental considerations are placed higher than purely economic considerations (IPCC B1 and B2 scenarios) compared with the climate associated with emissions resulting from the global free market scenario (IPCC A1FI scenario). More SOC is lost towards the end of the study period. Optimal management is able to reduce this loss of SOC, by up to 44% compared with business as usual management. The soil sustainability scenario could be run only for a limited area, but in that area was shown to increase SOC stocks under three climate scenarios, compared with a loss of SOC under business as usual management in the same area. Improved agricultural soil management will have a significant role to play in the adaptation to, and mitigation of, climate change in this region. Further, our results suggest that this adaptation could be realized without damaging profitability for the farmers, a key criteria affecting whether optimal management can be achieved in reality.  相似文献   
64.
Advances in plant molecular farming   总被引:1,自引:0,他引:1  
Plant molecular farming (PMF) is a new branch of plant biotechnology, where plants are engineered to produce recombinant pharmaceutical and industrial proteins in large quantities. As an emerging subdivision of the biopharmaceutical industry, PMF is still trying to gain comparable social acceptance as the already established production systems that produce these high valued proteins in microbial, yeast, or mammalian expression systems. This article reviews the various cost-effective technologies and strategies, which are being developed to improve yield and quality of the plant-derived pharmaceuticals, thereby making plant-based production system suitable alternatives to the existing systems. It also attempts to overview the different novel plant-derived pharmaceuticals and non-pharmaceutical protein products that are at various stages of clinical development or commercialization. It then discusses the biosafety and regulatory issues, which are crucial (if strictly adhered to) to eliminating potential health and environmental risks, which in turn is necessary to earning favorable public perception, thus ensuring the success of the industry.  相似文献   
65.
There have been relatively few studies examining sleep in patients withobsessive-compulsive disorder (OCD) and these have produced contradictoryfindings. A recent retrospective study identified a possible association betweenOCD and a circadian rhythm sleep disorder known as delayed sleep phase syndrome(DSPS). Patients with this pattern of sleeping go to bed and get up much laterthan normal. They are unable to shift their sleep to an earlier time and,as a result, suffer considerable disruption to social and occupational functioning.In this study, we examined the sleep of patients with OCD prospectively. Weaimed to establish the frequency of DSPS in this population and any associatedclinical or demographic factors which might be implicated in its aetiology.  相似文献   
66.
Fire can often occur in aquatic ecosystems, which may affect aquatic invertebrates. Despite the importance of aquatic invertebrates to ecosystem function, the effect of fire on these environments has been little studied. We studied the effects of fire on aquatic invertebrates in artesian springs in the arid zone of South Australia. Artesian springs are a unique and threatened ecosystem, containing several rare and endemic species. Evidence suggests these wetlands were routinely burnt by indigenous Aboriginal people before European settlement over 100 years ago. Recently, burning has been suggested as a reinstated management tool to control the dominant reed Phragmites australis. A reduction in the cover of the reed may benefit the threatened flora and fauna through enhancement of water flow. Three artesian springs were burnt and aquatic invertebrates sampled from the burnt and three unburnt springs. A single fire in late winter completely burnt the dominant vegetation, followed by recovery of Phragmites over the following 2 years. A single fire event did not deplete populations of endemic aquatic invertebrates in artesian springs, but probably did not substantially benefit these populations either. Isopods, amphipods, ostracods and three species of hydrobiid snail survived the fire event, and most had increased in number 1 month post fire but then returned to pre‐burnt numbers by 1 year post fire. Morphospecies richness of all identified invertebrates increased over time in all springs, but did not differ appreciably between burnt and unburnt springs. If burning artesian springs is to be adopted as a management tool to suppress the growth of Phragmites australis, we conclude that the endemic aquatic invertebrates will survive a single burn event, without negative effect to their populations.  相似文献   
67.
Abscisic acid (ABA)-induced stomatal closure is mediated by a complex, guard cell signalling network involving nitric oxide (NO) as a key intermediate. However, there is a lack of information concerning the role of NO in the ABA-enhanced stomatal closure seen in dehydrated plants. The data herein demonstrate that, while nitrate reductase (NR)1-mediated NO generation is required for the ABA-induced closure of stomata in turgid leaves, it is not required for ABA-enhanced stomatal closure under conditions leading to rapid dehydration. The results also show that NO signalling in the guard cells of turgid leaves requires the ABA-signalling pathway to be both capable of function and active. The alignment of this NO signalling with guard cell Ca2+-dependent/independent ABA signalling is discussed. The data also highlight a physiological role for NO signalling in turgid leaves and show that stomatal closure during the light-to-dark transition requires NR1-mediated NO generation and signalling.  相似文献   
68.
Three species of the genus ScathophagaS. mellipes (Coquillet), S. scybalaria (Linnaeus) and S. stercoraria (Linnaeus) – are treated in this study. Of these, S. scybalaria (Linnaeus) is reported for the first time from Korea. A key to the Korean species, their domestic localities and some illustrations are given.  相似文献   
69.
Ozone induces stomatal sluggishness, which impacts photosynthesis and transpiration. Stomatal responses to variation of environmental parameters are slowed and reduced by ozone and may be linked to difference of ozone sensitivity. Here we determine the ozone effects on stomatal conductance of each leaf surface. Potential causes of this sluggish movement, such as ultrastructural or ionic fluxes modification, were studied independently on both leaf surfaces of three Euramerican poplar genotypes differing in ozone sensitivity and in stomatal behaviour. The element contents in guard cells were linked to the gene expression of ion channels and transporters involved in stomatal movements, directly in microdissected stomata. In response to ozone, we found a decrease in the stomatal conductance of the leaf adaxial surface correlated with high calcium content in guard cells compared with a slight decrease on the abaxial surface. No ultrastructural modifications of stomata were shown except an increase in the number of mitochondria. The expression of vacuolar H+/Ca2+‐antiports (CAX1 and CAX3 homologs), β‐carbonic anhydrases (βCA1 and βCA4) and proton H+‐ATPase (AHA11) genes was strongly decreased under ozone treatment. The sensitive genotype characterized by constitutive slow stomatal response was also characterized by constitutive low expression of genes encoding vacuolar H+/Ca2+‐antiports.  相似文献   
70.
Rising atmospheric carbon dioxide (CO2) concentration is increasingly affecting food production but how plant diseases will influence production and quality of food under rising CO2 is not well understood. With increased plant biomass at high CO2 the stubble‐borne fungal pathogen Fusarium pseudograminearum causing crown rot (CR) of wheat may become more severe. We have studied inoculum production by Fusarium using fungal biomass per unit wheat stubble, stem browning from CR and the saprophytic fitness of Fusarium strains isolated from two wheat varieties grown in 2007 and 2008 at ambient and elevated CO2 in free‐air CO2 enrichment (FACE) with or without irrigation and once in a controlled environment. Fungal biomass, determined using primers for fungal ribosomal 18s and the TRI5 gene, increased significantly at elevated CO2 in two of the three studies. Stem browning increased significantly at elevated CO2 in the 2007 FACE study. At elevated CO2 increased stem browning was not influenced by irrigation in a susceptible variety but in a resistant variety stem browning increased by 68% without irrigation. Wheat variety was significant in regression models explaining stem browning and Fusarium biomass but pathogen biomass at the two CO2 levels was not significantly linked to stem browning. Fusarium isolates from ambient and elevated CO2 did not differ significantly in their saprophytic fitness measured by the rate of colonization of wheat straw. We show that under elevated CO2Fusarium inoculum in stubbles will be amplified from increased crop and pathogen biomass while unimpeded saprophytic fitness will retain its effectiveness. If resistant varieties cannot completely stop infection, Fusarium will rapidly colonize stubble to further increase inoculum once the crop is harvested. Research should move beyond documenting the influence of elevated CO2 to developing disease management strategies from improved knowledge of pathogen biology and host resistance under rising CO2.  相似文献   
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