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Md. Samim Hossain Molla Sutkhet Nakasathien Md. Akkas Ali ASMMR Khan Md. Robiul Alam 《Archives of Agronomy and Soil Science》2019,65(7):928-944
Plants have evolved different mechanisms to survive under stress conditions. This field study was conducted to evaluate the influence of nitrogen (N) application on dry biomass allocation and translocation in two maize varieties under short pre-anthesis and prolonged bracketing flowering period of drought. Two maize varieties, ‘Pioneer 30B80? and ‘Suwan 4452? receiving N at 0 (control), 160 (optimal) and 320 (supra-optimal) kg ha?1 were subjected to short pre-anthesis and prolonged bracketing flowering periods of drought. Prolonged bracketing flowering period of drought had more suppressive effect on anthesis-silking interval, dry matter allocation and translocation, leaf greenness, contribution of current assimilates to grain (CCAG), kernel number, kernel weight and kernel yield of two maize varieties than a short pre-anthesis drought. Nitrogen application at optimal level was the best for all traits, except CCAG. The maize variety ‘Pioneer 30B80? performed better under both drought types due to more root xylem vessels of large size and more accumulation of dry matter in leaves and roots than the variety ‘Suwan 4452?. Therefore, the variety ‘Pioneer 30B80? may be planted in drought prone environments and may be used in breeding program aimed at developing drought-tolerant cultivars. 相似文献
43.
Our knowledge of diseases in New Zealand wildlife has expanded rapidly in the last two decades. Much of this is due to a greater awareness of disease as a cause of mortality in some of our highly threatened species or as a limiting factor to the successful captive rearing of intensely managed species such as hihi (Notiomystis cincta), kiwi (Apteryx spp.) and kakapo (Strigops habroptilus). An important factor contributing to the increase of our knowledge has been the development of new diagnostic techniques in the fields of molecular biology and immunohistochemistry, particularly for the diagnosis and epidemiology of viral and protozoan diseases. Although New Zealand remains free of serious exotic viruses there has been much work on understanding the taxonomy and epidemiology of local strains of avipox virus and circoviruses. Bacterial diseases such as salmonellosis, erysipelas and tuberculosis have also been closely investigated in wildlife and opportunist mycotic infections such as aspergillosis remain a major problem in many species. Nutritional diseases such as hyperplastic goitre due to iodine deficiency and metabolic bone disease due to Ca:P imbalance have made significant impacts on some captive reared birds, while lead poisoning is a problem in some localities. The increasing use of wildlife translocations to avoid the extinction of threatened species has highlighted the need for improved methods to assess the disease risks inherent in these operations and other intensive conservation management strategies such as creching young animals. We have also become more aware of the likelihood of inbreeding suppression as populations of many species decrease or pass through a genetic bottleneck. Climate change and habitat loss, however, remain the greatest threats to biodiversity and wildlife health worldwide. Temperature changes will affect our wildlife habitats, alter the distribution of disease vectors and wildlife predators, or directly harm threatened species in vulnerable localities. 相似文献
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Yatoo Mohd. Iqbal Parray Oveas Raffiq Mir Muheet Bhat Riyaz Ahmed Malik Hamid Ullah Fazili Mujeeb ur Rehman Qureshi Sabia Mir Masood Salim Yousuf Raja Wasim Tufani Noor Alam Dhama Kuldeep Bashir Shah Tauseef 《Tropical animal health and production》2019,51(8):2127-2137
Tropical Animal Health and Production - Therapeutic management of contagious caprine pleuroneumonia (CCPP) involves mostly the use of oxytetracycline followed by enrofloxacin and rarely tylosin. In... 相似文献
45.
Reconstructing past ocean pH-depth profiles 总被引:1,自引:0,他引:1
Measurement of boron isotope compositions in species of planktonic foraminifera that calcified their tests at different depths in the water column are used to reconstruct the pH profile of the upper water column of the tropical ocean. Results for five time windows from the middle Miocene to the late Pleistocene indicate pH-depth profiles similar to that of the modern ocean in this area, which suggests that this method may greatly aid in our understanding of the global carbon cycle. 相似文献
46.
Pinus gerardiana Wall. is an important nut-producing pine having restricted distribution in the world. It has been observed that natural regeneration in the species is extremely poor or entirely lacking. The species has erratic and infrequent seed years, dormancy-related problems, and slow growth of seedling, which reduces its regeneration process in natural habitats. Therefore, we investigated the effect of growing medium and seed size on germination and seedling growth of the Pinus gerardiana. The seeds were categorized into two sizes, viz, small (<2.35 cm) and large (>2.35 cm) and five growing medium treatments were used, viz, Soil:Sand:FYM; Soil:Sand:Moss:FYM; Soil:Moss:Vermicompost; Soil:Sand:Vermicompost; and Soil:Sand:Moss:Vermicompost, for assessing their impact on germination and seedling growth. It was observed that, among different growing medium treatments, higher germination and seedling growth parameters were recorded, when Soil:Sand:Moss:Vermicompost was used for the study. Between different seed sizes, higher germination and seedling growth were recorded when seed size was large. 相似文献
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48.
Alam MJ Renter DG Ives SE Thomson DU Sanderson MW Hollis LC Nagaraja TG 《Veterinary research》2009,40(1):2-Feb;40(1):02
A prospective cohort study was used to assess whether Salmonella fecal shedding in commercial feedlot cattle treated with antimicrobials for respiratory disease was associated with subsequent adverse health outcomes. Feces were collected per rectum from cattle that were examined for apparent respiratory disease, had a rectal temperature > or = 40 degrees C, and subsequently received antimicrobial treatment. Salmonella were recovered from 918 (73.7%) of 1 245 fecal samples and weekly prevalence estimates ranged from 49 to 100% over the 3-month study. Genotypic and phenotypic characteristics of Salmonella strains in the population were determined. Serogroup E Salmonella were most common (73.3%), followed by C1 (11.0%), C3 (8.6%), and B (1.1%). Predominant serotypes were Orion (46.5%), Anatum (19.8%), Kentucky (8.7%), Montevideo (7.5%), and Senftenberg (4.9%). Few isolates (36/918) were positive for antimicrobial resistance-associated integron gene intI1. Phenotypic susceptibility was associated with isolate intI1 status. Crude re-pull, re-treatment and case fatality risks were higher for cattle that were Salmonella-positive versus -negative at initial treatment, but not statistically different on multivariable analysis. However, case fatality risk was higher for cattle shedding Group B Salmonella than for cattle shedding other serogroups. Lots (groups) with a higher Salmonella prevalence at first treatment had a higher proportion of mortalities occur in a hospital pen, higher overall re-treatment risks, and were more likely to be sampled later in the study. Results indicate a high prevalence of Salmonella in this population of cattle treated for apparent respiratory disease, but that effects associated with clinical outcomes may depend on the Salmonella strain. 相似文献
49.
BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [3H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [3H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry 相似文献
50.