不同灌水量下限对高羊茅绿期及抗寒性生理指标的影响

采用盆栽试验的方法，研究了秋末冬初不同灌水量下限\分别占田间持水量(FC)的80%、70%、60%、50%\]对高羊茅绿期及抗寒性生理指标的影响.结果表明：在冬季低温条件下，80%和70%FC灌水处理使高羊茅叶片相对含水量、保护酶(SOD、POD和CAT)活性、叶绿素、可溶性糖和游离脯氨酸含量维持在较高水平，丙二醛含量和电解质外渗率降低，高羊茅的抗寒性增强.80%FC灌水处理分别较70%、60%和50%FC处理的草坪草绿期延长4、22和28 d，到达枯黄休眠的时间最晚，完成返青的时间最早.综合考虑节水和提高水分利用效率等多种因素，70%FC灌水处理为高羊茅秋末冬初季节最佳的灌水下限.

Effects of enhanced UV-B radiation on physiological characteristics of Bryum argenteum

Taking the biological soil crust(Bryum argenteum) broadly existed in the Tengger Desert of China as test object,this paper studied the effects of UV-B radiation on the photosynthesis,cell membrane integrality,water-soluble protein content,and antioxidant enzymes activities of B.argenteum under laboratory condition.UV-B radiation decreased the chlorophyll content,chlorophyll fluorescence parameters,water-soluble protein content,and antioxidant enzymes activities of B.argenteum significantly,with the decrements positively proportional to the radiation intensity,while increased the malondiadehyde and carotenoid contents,with the increments increased with increasing radiation intensity.These results indicated that enhanced UV-B radiation intensity caused a significant reduction in the photosynthetic rate,cell membrane damage,and disorder of antioxidant enzyme system,but the increase of the carotenoid content with increasing radiation intensity could be one of the self-protection mechanisms of B.argenteum in resisting UV-B stress.