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11.
Chen ZY Jing D Bath KG Ieraci A Khan T Siao CJ Herrera DG Toth M Yang C McEwen BS Hempstead BL Lee FS 《Science (New York, N.Y.)》2006,314(5796):140-143
A common single-nucleotide polymorphism in the brain-derived neurotrophic factor (BDNF) gene, a methionine (Met) substitution for valine (Val) at codon 66 (Val66Met), is associated with alterations in brain anatomy and memory, but its relevance to clinical disorders is unclear. We generated a variant BDNF mouse (BDNF(Met/Met)) that reproduces the phenotypic hallmarks in humans with the variant allele. BDNF(Met) was expressed in brain at normal levels, but its secretion from neurons was defective. When placed in stressful settings, BDNF(Met/Met) mice exhibited increased anxiety-related behaviors that were not normalized by the antidepressant, fluoxetine. A variant BDNF may thus play a key role in genetic predispositions to anxiety and depressive disorders. 相似文献
12.
Increasing water scarcity has necessitated the development of irrigated rice systems that require less water than the traditional
flooded rice. The cultivation of aerobic rice is an effort to save water in response to growing worldwide water scarcity with
the pressure to reduce water use and increase water productivity. An accurate estimation of different water balance components
at the aerobic rice fields is essential to achieve effective use of limited water supplies. Some field water balance components,
such as percolation, capillary rise and evapotranspiration, can not be easily measured; therefore a soil water balance model
is required to develop and to test water management strategies. This paper presents results of a study to quantify time varying
water balance under a critical soil water tension based irrigation criteria for the cultivation of non-ponded “aerobic rice”
fields along the lower parts of the Yellow River. Based on the analysis and integration of existing field information on the
hydrologic processes in an aerobic rice field, this paper outlines the general components of the water balance using a conceptual
model approach. The time varying water balance is then analyzed using the feedback relations among the hydrologic processes
in a commercial dynamic modeling environment, Vensim. The model simulates various water balance components such as actual
evapotranspiration, deep percolation, surface runoff, and capillary rise in the aerobic rice field on a daily basis. The model
parameters are validated with the observed experimental field data from the Huibei Irrigation Experiment Station, Kaifeng,
China. The validated model is used to analyze irrigation application soil water tension trigger under wet, dry and average
climate conditions using daily time steps. The scenario analysis show that to conserve scarce water resources during the average
climate years the irrigation scheduling criteria can be set as −30 kPa average root zone soil water tension; whereas it can
be set at −70 kPa during the dry years, however, the associated yields may reduce. Compared with the flooded lowland rice
and other upland crops, with these two alternatives irrigation event triggers, aerobic rice cultivation can lead to significant
water savings. 相似文献
13.
Masahiko Suzuki Md Sirajul Islam Khan Arihiro Iwasaki Kiyotake Suenaga Hisashi Kato-Noguchi 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(1):37-42
The present study was aimed to determine the allelopathic potential of mango (Mangifera indica L.) leaves and to identify allelopathic substances in the leaves. The aqueous methanol extracts of mango leaves inhibited seedling growth of garden cress, radish, rapeseed, foxtail fescue and crabgrass, and the inhibitory effects increased with the increasing extract concentration, suggesting that mango leaves may contain allelopathic substances. The extract was then purified by several chromatographic runs through a bioassay-directed fractionation, and an growth inhibitory substance was isolated and identified by spectral data as methyl-3,4,5-trihydroxybenzoate (methyl gallate). Methyl gallate at the concentration of 10 mM inhibited 98.6% and 99.8% of root and shoot growth of garden cress relative to the control, respectively, and 94.4% and 49.3% of those of foxtail fescue, respectively. The concentrations of methyl gallate required for 50% growth inhibition (I50) on garden cress roots and shoots were 3.9 and 3.3 mM, and those on foxtail fescue roots and shoots were 1.5 and 9.5 mM, respectively. It is the first report of an allelopathic substance in mango leaves and allelopathic activity of methyl gallate. Therefore, the mango leaves may have potential as a soil additive material for the weed management options. 相似文献
14.
Dandan Zhu Jianglin Zhang Zheng Wang Rizwan Khan Muhammad Jianwei Lu Xiaokun Li 《Soil Use and Management》2019,35(3):503-510
Data from 147 field trials were collected to study the influence of straw incorporation on soil potassium (K) under an intensive rice–oilseed rape rotation system, while pot experiments were conducted to evaluate the effects of rice straw incorporation on soil K availability. A significant correlation was observed between the soil available K and the relative yield (RRY) and the relative K uptake (RKU) of oilseed rape, with R2 values ranging from 0.07 to 0.08 and from 0.10 to 0.11, respectively, when data were fitted to a logarithmic equation model. In approximately 30% of trials, RRY reached 90%, while soil test available K values were below the critical limit, indicating that soil K values at the time of sampling (within 1 week of rice harvest) underestimated the actual soil K supply capacity. The pot experiment results showed that soil available K was affected by straw incorporation and soil type in the fallow period. The NH4OAc‐K and NaBPh4‐K concentrations of soils increased at first, and then, plateaued after 28 days. Straw incorporation significantly influenced the critical soil K concentration, which is important for making accurate K fertilizer recommendation. These results suggested that straw K should be seriously considered in making K fertilizer recommendations. Extending the sampling time from 1 to 3 weeks after the harvesting of rice to stabilize the effects of straw incorporation may help achieve a more accurate evaluation of soil available K. 相似文献
15.
Comprehensive emission inventories for 2001 and 2004 for Kuwait’s main power stations located at Al-Doha and Al-Subyia have been prepared. These inventories are inserted, in conjunction with meteorological data, into the Source Complex model for Short Term Dispersion (ISCST4.5) to predict ambient ground level concentrations of sulphur dioxide (SO2) and nitrogen oxides (NOx) at selected receptors for years 2001 and 2004. The comparison of the results obtained for these 2 years show the influence of increase in emission rates due to urban and industrial growth. For model validation, computed results are compared with the measured daily average values of SO2 and NOx collected at a fixed Kuwait Environment Protection Agency air quality monitoring station located at the roof of polyclinic in Rabia. Individual contributions of each power station to the highest predicted values are assessed. The five highest hourly, daily and annual ground level concentration values under prevailing meteorological conditions are compared for 2001 and 2004. It is found that the hourly mean concentrations are strongly influenced by the prevailing meteorological conditions. The effect of meteorological conditions has not been that dominant for the daily and annual mean values and the predicted values for 2004 are higher than 2001, simply corresponding to a high emission rates, especially in summer months. Top 50 daily average values of SO2 show a slope of 0.806 for 2001 which means that the model predictions are 20% less than the observed levels. However, the predicted slope of SO2 for 2004 is 0.96 and the model predictions are in very close agreement with the observed data. 相似文献
16.
Khalid S. Khan Andreas Gattinger Franz Buegger Michael Schloter Rainer Georg Joergensen 《Soil biology & biochemistry》2008,40(5):1217-1224
An incubation experiment was carried out to investigate whether salinity at high pH has negative effects on microbial substrate use, i.e. the mineralization of the amendment to CO2 and inorganic N and the incorporation of amendment C into microbial biomass C. In order to exploit natural differences in the 13C/12C ratio, substrate from two C4 plants, i.e. highly decomposed and N-rich sugarcane filter cake and less decomposed N-poor maize leaf straw, were added to two alkaline Pakistani soils differing in salinity, which had previously been cultivated with C3 plants. In soil 1, the additional CO2 evolution was equivalent to 65% of the added amount in the maize straw treatment and to 35% in the filter cake treatment. In the more saline soil 2, the respective figures were 56% and 32%. The maize straw amendment led to an identical immobilization of approximately 48 μg N g−1 soil over the 56-day incubation in both soils compared with the control soils. In the filter cake treatment, the amount of inorganic N immobilized was 8.5 μg N g−1 higher in soil 1 than in soil 2 compared with the control soils. In the control treatment, the content of microbial biomass C3-C in soil 1 was twice that in soil 2 throughout the incubation. This fraction declined by about 30% during the incubation in both soils. The two amendments replaced initially similar absolute amounts of the autochthonous microbial biomass C, i.e. 50% of the original microbial biomass C in soil 1 and almost 90% in soil 2. The highest contents of microbial biomass C4-C were equivalent to 7% (filter cake) and 11% (maize straw) of the added C. In soil 2, the corresponding values were 14% lower. Increasing salinity had no direct negative effects on microbial substrate use in the present two soils. Consequently, the differences in soil microbial biomass contents are most likely caused indirectly by salinity-induced reduction in plant growth rather than directly by negative effects of salinity on soil microorganisms. 相似文献
17.
Jan Sami Khan M. N. Jan Sofora Zaffar Aaqif Rashid Rizwan Khan M. A. Sheikh F. A. Bhat M. Ashraf Mir R. R. 《Genetic Resources and Crop Evolution》2022,69(2):661-676
Genetic Resources and Crop Evolution - Barley (Hordeum vulgare L.) is one of the principal cereal crops grown in Western-Himalayas of India. A set of 105 barley genotypes including 38... 相似文献
18.
Mohammad Afzal Khan Ahmad Khalil Jafri & Narendra Kumar Chadha 《Aquaculture Research》2004,35(13):1277-1285
Growth, reproductive performance, muscle and egg composition were investigated in grass carp, Ctenopharyngodon idella (Valenciennnes), fed hydrilla or formulated diets with varying protein levels. Five experimental diets, with varying levels (20%, 25%, 30%, 35% and 40%) of crude protein (CP), were used. One of the fish groups was fed hydrilla. Fish (44.1±0.3 cm; 913±9 g) were stocked (20 tank?1) in outdoor concrete tanks (20 × 10 × 1.5 m) in duplicate, and fed to satiation, twice daily, at 09:00 and 17:00 hours for the experimental duration of 360 days. High (P<0.05) weight gain was recorded in fish fed 30% and 35% CP diets. However, values for gonadosomatic index (GSI), egg diameter, relative fecundity (eggs kg?1 body weight), fertilizability and hatchability (%) were comparable (P>0.05) in fish at ≥25% of dietary protein intake. Hydrilla‐fed fish exhibited lower (P<0.05) values for the measured parameters. Crude protein content in muscle increased with dietary protein level. Highest (P<0.05) muscle protein was obtained in fish fed 35% CP diet. Muscle fat was comparable (P>0.05) among fish receiving formulated diets. Ash content was not significantly (P>0.05) different among fish of different dietary groups. Moisture content in fish fed formulated diets, with the exception of 20% CP diet, did not vary significantly (P>0.05). Eggs of fish fed formulated diets contained higher CP and fat contents than those of hydrilla‐fed fish. High (P<0.05) moisture content was noted in the eggs of hydrilla‐fed fish. Ctenopharyngodon idella fed formulated diet, with a minimum of 25% CP, showed better reproductive performance than those fed hydrilla. 相似文献
19.
M. Arif N. W. Zaidi Q. M. R. Haq Y. P. Singh S. Khan U. S. Singh 《Forest Pathology》2013,43(6):478-487
Sissoo (Dalbergia sissoo), commonly known as shisham, is amongst the finest woods of South Asia, but ‘wilt’ disease has caused a rapid decline in this species. The cause of the disease remains uncertain. The aim of this study is to identify the causal agent of the disease and characterize isolates made from diseased trees, based on genomic data and variations in virulence. Samples of infected roots, stems and the ooze exuded from infected trees were obtained from plants showing symptoms in different geographical regions of India for the isolation of microorganisms. Isolates were used to inoculate healthy plants. Based on the morphological characteristics, genus‐ and species‐specific PCR, and in silico analysis of 5.8S rDNA‐ITS regions, of the 38 fungal isolates, 24 and 14 were identified as Fusarium solani and Fusarium sp., respectively. In a pathotyping study, eighteen F. solani isolates, isolated from roots and stem parts of symptomatic plants, induced typical wilt symptoms when inoculated through soil and roots on D. sissoo seedlings of 1–15 months in age. The population of F. solani was the highest in infected roots and the lowest in parts of stems, gradually decreasing with height, and was isolated constantly up to approximately 40% height of the seedling. F. solani isolates used in inoculations were successfully re‐isolated from the rhizosphere, infected roots and wilted stems, as confirmed using isolate‐specific DNA fingerprints. Molecular phylogenies based on rDNA‐ITS sequences showed that the 38 isolates fell into 2 groups. Group I comprised of F. solani isolates from D. sissoo and F. solani sequences in the NCBI GenBank database, whereas group II included Fusarium isolates other than F. solani. These results are helpful in developing integrated control measures for this highly variable pathogen and to establish a base for future population studies. 相似文献
20.
The predatory mite Typhlodromus pyri Scheuten (Acari, Phytoseiidae) has been reported as an important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture and vineyards at below 25?°C. However, sufficient biological data was lacking on its efficiency at temperatures above 25?°C. Therefore, the purpose of the present laboratory work was to obtain experimental data on prey consumption during development as well as longevity and reproduction of T. pyri on apple leaf discs and in Plexiglas cells at constant temperatures of 25?±?2?°C and 30?±?2?°C with P. ulmi as prey. 相似文献