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961.
In this paper, we studied the nocturnal stem water recharge of Acacia mangium. It is helpful to improve the precision of canopy transpiration estimation and canopy stomatal conductance, and to further understand the lag time of canopy transpiration to stem sap flow. In this study, the whole-tree sap flow in an A. mangium forest was measured by using Granier’s thermal dissipation probe for over two years in the hilly land of South China. The environmental factors, including relative humidity (RH), precipitation, vapor pressure deficit (VPD), photosynthetically active radiation (PAR), and air temperature (T a) were recorded simultaneously. The stem water recharge of A. mangium was analyzed on both daily and monthly scales. Sap flux density was lower at night than during the day. The time range of nighttime sap flux density was longer in the dry season than in the wet season. The water recharging mainly occurred from sunset to midnight. No significant differences were observed among inter-annual nighttime water recharges. Nighttime water recharge had no significant correlation with environmental factors, but was well correlated with the diameter at breast height, tree height, and crown size. In the dry season the contribution of nighttime water recharge to total transpiration had significant correlations with daytime transpiration, total transpiration, VPD, PAR and T a, while in the wet season it was significantly correlated with daily transpiration and total transpiration. __________ Translated from Chinese Journal of Ecology, 2007, 26(4): 476–482 [译自: 生态学杂志]  相似文献   
962.
 对65个不同来源的早籼稻品种进行了灌浆期耐热性的鉴定研究,并比较了耐热性相差很大的品种灌浆期高温胁迫前后的生理反应。结果表明:秕粒率、实粒重、整精米率、垩白度、蛋白质含量的胁迫指数可作为水稻品种灌浆期耐热性田间直接鉴定的 5个指标,可采用隶属函数值法对各品种的耐热性进行综合评价;不同品种的耐热性存在相当大的差异,筛选出了几个耐热性很强的品种;高温胁迫严重影响水稻的光合能力,但耐热性强的品种剑叶的光合速率高温胁迫后下降幅度明显较小,胁迫解除后恢复的程度也更高,叶绿素含量、RuBPc 活性及内源多胺含量的变化趋势与光合速率相一致,是水稻耐高温逼熟的重要生理特征。  相似文献   
963.
Curcumin, the yellow color pigment of turmeric, is produced industrially from turmeric oleoresin. The mother liquor after isolation of curcumin from oleoresin contains approximately 40% oil. The oil was extracted from the mother liquor using hexane at 60 degrees C, and the hexane extract was separated into three fractions using silica gel column chromatography. These fractions were tested for antibacterial activity by pour plate method against Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Fraction II eluted with 5% ethyl acetate in hexane was found to be most active fraction. The turmeric oil, fraction I, and fraction II were analyzed by GC and GC-MS. ar-Turmerone, turmerone, and curlone were found to be the major compounds present in these fractions along with other oxygenated compounds.  相似文献   
964.
 Soil P availability and efficiency of applied P may be improved through an understanding of soil P dynamics in relation to management practices in a cropping system. Our objectives in this study were to evaluate changes in plant-available (Olsen) P and in different inorganic P (Pi) and organic P (P0) fractions in soil as related to repeated additions of manure and fertilizer P under a soybean-wheat rotation. A field experiment on a Typic Haplustert was conducted from 1992 to 1995 wherein the annual treatments included four rates of fertilizer P (0, 11, 22 and 44 kg ha–1 applied to both soybean and wheat) in the absence and presence of 16 t ha–1 of manure (applied to soybean only). With regular application of fertilizer P to each crop the level of Olsen P increased significantly and linearly through the years in both manured and unmanured plots. The mean P balance required to raise Olsen P by 1 mg kg–1 was 17.9 kg ha–1 of fertilizer P in unmanured plots and 5.6 kg ha–1 of manure plus fertilizer P in manured plots. The relative sizes of labile [NaHCO3-extractable Pi (NaHCO3-Pi) and NaHCO3-extractable P0 (NaHCO3-P0)], moderately labile [NaOH-extractable Pi (NaOH-Pi) and NaOH-extractable P0 (NaOH-P0)] and stable [HCl-extractable P (HCl-P) and H2SO4/H2O2-extractable P (resisual-P)] P pools were in a 1 : 2.9 : 7.6 ratio. Application of fertilizer P and manure significantly increased NaHCO3-Pi and -P0 and NaOH-Pi, and -P0 fractions and also total P. However, HCl-P and residual-P were not affected. The changes in NaHCO3-Pi, NaOH-Pi and NaOH-P0 fractions were significantly correlated with the apparent P balance and were thought to represent biologically dynamic soil P and act as major sources and sinks of plant-available P. Received: 23 October 1997  相似文献   
965.
Genetic basis of variation for salt tolerance in maize ( Zea mays L).   总被引:2,自引:0,他引:2  
The genetic basis of salt tolerance was examined in selected salt tolerant and sensitive material from a sample of accessions previously assessed for variability in salinity tolerance. The North Carolina Model 2 Design and analysis was followed, tolerance being assessed in 10-day-old seedlings grown in salinized solution culture at control (0 mM), 60 mM and 80 mM NaCl concentrations). Salinity tolerance was shown to be under the control of genes with additive and non-additive effects, with broad and narrow sense heritability estimates being approximately 0.7 and 0.4 over all treatments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
966.
The effect of three pesticides, benomyl, carbofuran and gamm-BHC at 5 parts 106, rates equivalent to recommended field levels, on the heterotrophic N2 fixation in five air-dried, cellulose-amended, submerged tropical soils was invevstigated employing 15N tracer technique under laboratory conditions. Addition of benomyl, a carbamate fungicide, to alluvial, laterite and two acid sulphate soils resulted in significant increases in N2 fixation, while carbofuran, a methylcarbamate insecticide, exerted a stimulatory effect on N2 fixation in alluvial, alterite and acid saline soils. Gamma-BHC, a chlorinated hydrocarbon insecticide, stimulated N2 fixation in alluvial and acid sulphate pokkali solis, while considerable inhibition of N2 fixation was evident inother soils. Results showed differential responses of specific groups of N2-fixing organisms to the pesticides depending ont he soil type.  相似文献   
967.
Composite fish culture of the Indian major carp, Catla catla, Labeo rohita and Cirrhinus mrigala together with the Chinese silver carp Hypophthalmichthys molitrix and grass carp Ctenopharyngodon idella and the Indonesian strain of common carp (Cyprinus carpio communis) was carried out in experimental ponds in 1971–1972 and 1973–1974. The management techniques adopted aimed at high yields of marketable fish (around 1 kg) in 1 year.In the first year, production varied from 3 889 to 5 600 kg/ha/year and this rose to an average of 8 200 kg/ha/year with a maximum of 9 389 kg/ha/year in the second year. The important changes made to the management schedule in 1973 were increased stocking density, greater use of feed and fertilizers, and provision of more weeds for grass carp.The experimental studies demonstrate the practicability of raising large crops of healthy marketable fish in India.  相似文献   
968.
饶珠阳 《广西农学报》2006,22(2):13-16,23
本试验选用三元杂肉猪作为试验动物,随机分成4组,分别在肉猪的基础饲粮中添加微生态制剂-宝肠安和抗生素-土霉素添加剂,并与空白对照组进行为期39天的比较研究试验。结果表明,饲粮中添加微生态制剂可提高肉猪饲料转化效率和饲养效益,猪的增重、采食量及抗病率等与使用土霉素的相当,并且消除猪粪异臭、改善环境等效果较土霉素理想。微生态制剂替代土霉素等抗生素具有明显的综合效益。  相似文献   
969.
This research was undertaken to find an efficient tissue culture system and Agrobacterium-mediated genetic transformation method for recalcitrant indica rice cultivars. For this, mature seeds of commercially important indica rice varieties, ASD16, ADT43, IR 64, and Pusa Basmati were cultured on MS and N6 medium supplemented with 2 mg l-1 2, 4-D + 30 g l-1 sucrose. The calli grown in N6 medium showed better friability and embryogenic response. Out of the four varieties tested, ASD16 and IR64 showed better callusing and embryogenic capacity as compared to ADT43 and Pusa Basmati. For genetic transformation studies, embryogenic calli of all the cultivars were co-cultivated with the Agrobacterium tumefaciens strain LBA 4404 harboring the binary vector pCambia 1305.1 with GUS gene. GUS assay was performed for the putative transformed calli and its activity was found to be qualitatively higher in ASD16 and IR64 than the other two varieties. The best responsive ASD16 transformed calli was regenerated and the putative transgenic lines were regenerated. ASD16 transformed calli were confirmed by GUS assay. PCR analysis confirmed the presence of both GUS and HPT genes in ASD16 transgenic lines.  相似文献   
970.
Helicoverpa armigera (Hübner) (Noctuidae: Lepidopetra) is a polyphagous pest of major crops grown in India. To prevent the damage caused by H. armigera farmers rely heavily on insecticides of diverse groups on a regular basis which is not a benign practice, environmentally and economically. To provide more efficient and accurate information on timely application of insecticides, this research was aimed to develop a forecast model to predict population dynamics of pod borer using Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Networks (ANN). The data used in this study were collected from the randomly installed sex pheromone traps at International Crops Research Institute for the Semi-arid Tropics (ICRISAT), Patancheru, Hyderabad. Several ARIMA (p, d, q) (P, D, Q) and ANN models were developed using the historical trap catch data. ARIMA model (1,0,1), (1,0,2) with minimal BIC, RMSE, MAPE, MAE, and MASE values and higher R2 value (0.53) was selected as the best ARIMA fit model, and neural network (7-30-1) was found to be the best fit to predict the catches of male moths of pod borer from September 2021 to August 2023. A comparative analysis performed between the ARIMA and ANN, shows that the ANN based on feed forward neural networks is best suited for effective pest prediction. With the developed ARIMA model, it would be easier to predict H. armigera adult population dynamics round the year and timely intervention of control measures can be followed by appropriate decision-making schedule for insecticide application.  相似文献   
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