低温胁迫下草坪草抗寒性的研究进展

通过介绍低温对草坪草的影响和作用机理,系统地综述了在低温胁迫下草坪草的光合特性、水分生理代谢、细胞质膜相对透性、保护酶系变化、碳水化合物贮藏、可溶性蛋白质含量、以及脂肪酸的变化在低温胁迫方面的研究进展,提出了今后进行草坪草抗寒性研究的趋势和建议。     

半地下带保温夹套发酵罐的应用

通过对半地下带保温夹套的发酵罐与普通发酵罐24 h的温度变化和6 d的产气量的对比试验分析,结果表明:采用半地下带保温夹套发酵罐发酵,24 h的温度变化缓慢,受外界温度变化影响小,高温持续的时间较长,利于微生物发酵;产气总量多,持续时间长。     

气候变化对秃尾河流域径流量的影响

为探讨秃尾河流域径流量对气候变化的关系,利用秃尾河流域1970～2005年36 a来的气温、降水和天然径流量数据,对该流域气温、降水和径流量年际和季节性的变化特征及趋势进行了分析,研究了气候因子与径流量的相关性.研究结果表明:秃尾河流域年平均气温呈现明显升高趋势,以冬季升温为主；年降水表现为缓慢减少趋势,降水减少主要表...     

The influence of temperature on the growth and sulfur uptake of oats (Avena sativa L.)

Abstract

Oats were grown in perlite and nutrient solution at temperatures varying from 10/5°C (day/night) to 36/31°C. The optimum temperature for growth of tops was found to be 27°C day/22°C night over an eight week period. Plant S content showed an inverse relationship with yield.

Uptake of S was low at low temperature (10/5, 15/10°C), but was balanced by retarded growth at this temperature. Hence, uptake did not restrict growth at low temperature.     

Oral administration of L-citrulline changes the concentrations of plasma hormones and biochemical profile in heat-exposed broilers

We examined the effects of oral administration of L-citrulline (L-Cit) on plasma metabolic hormones and biochemical profile in broilers. Food intake, water intake, and body temperature were also analyzed. After dual oral administration (20 mmol/head/administration) of L-Cit, broilers were exposed to a high ambient temperature (HT; 30 ± 1°C) chamber for 120 min. Oral administration of L-Cit reduced (p < .001) rectal temperature in broilers. Food intake was increased (p < .05) by heat stress, but it was reduced (p < .05) by L-Cit. Plasma levels of 3,5,3′-triiodothyronine, which initially increased (p < .0001) due to heat stress, were reduced (p < .01) by oral administration of L-Cit. Plasma insulin levels were increased by heat exposure (p < .01) and oral L-Cit (p < .05). Heat stress caused a decline (p < .05) in plasma thyroxine. Plasma lactic acid (p < .05) and non-esterified fatty acids (p < .01) were increased in L-Cit-treated heat-exposed broilers. In conclusion, our results suggest that oral L-Cit can modulate plasma concentrations of major metabolic hormones and reduces food intake in broilers.     

Interrelationship of soil moisture and temperature to sylvatic plague cycle among prairie dogs in the Western United States

Plague, caused by Yersinia pestis, is a flea-borne disease that is endemic in areas throughout the world due to its successful maintenance in a sylvatic cycle, mainly in areas with temperate climates. Burrowing rodents are thought to play a key role in the enzootic maintenance as well as epizootic outbreaks of plague. In the United States, prairie dogs (Cynomys), rodents (Muridae), and ground squirrels (Spermophilus) are susceptible to infection and are parasitized by fleas that transmit plague. In particular, prairie dogs can experience outbreaks that rapidly spread, which can lead to extirpation of colonies. A number of ecological parameters, including climate, are associated with these epizootics. In this study, we asked whether soil parameters, primarily moisture and temperature, are associated with outbreaks of plague in black-tailed prairie dogs and Gunnison's prairie dogs in the Western United States, and at what depth these associations were apparent. We collected publicly available county-level information on the occurrence of population declines or colony extirpation, while historical soil data was collected from SCAN and USCRN stations in counties and states where prairie dogs have been located. The analysis suggests that soil moisture at lower depths correlates with colony die-offs, in addition to temperature near the surface, with key differences within the landscape ecology that impact the occurrence of plague. Overall, the model suggests that the burrow environment may play a significant role in the epizootic spread of disease amongst black-tailed and Gunnison's prairie dogs.     

微灌地膜的节水保墒增温效应研究

在实验基础上 ,分析论述了微灌地膜的节水效果和增温保墒效应。试验结果表明 ,微灌地膜可比地面灌溉节水 61 % ,增加地温 3℃～ 6℃ ,近地面空气相对湿度提高 3 0 %～ 40 % ,综合效应明显。可供微灌地膜或膜下微灌的进一步研究设计参考     

地温空调井抽回灌效果影响关键因子识别

为了探析引起地温空调井抽回灌效果的主要制约因素,通过单相关系数分析、主成分绝对得分的源解析模型、拟合度检验和多元线性回归的方法分析影响单井回灌效率的影响因素。结果表明:井径、滤水管孔隙率及抽回灌井数比与单井回灌效率的相关性和拟合度较好,故将井径、滤水管孔隙率及抽回灌井数比作为影响单井回灌效率的关键因子,同时分析了单井回灌效率与关键因子的之间的拟合方程及多元线性回归方程,得到了单井回灌效率与关键因子之间的定量关系。