四季竹对土壤水分胁迫的生理适应

以四季竹2年生竹苗为材料,采用每天补水控制土壤含水量的方法,设置土壤相对含水率为<30%(T1)、40%～50%(T2)、60%～70%(T3)、80%～90%(T4)和竹蔸部完全水淹(T5)5个土壤水分含量水平,研究四季竹叶片在水分胁迫下的生理活性变化,以探讨四季竹对土壤水分的适应能力。结果表明:(1)随处理时间的延长,T1处理叶片离子渗漏率、MDA含量、叶绿素a/b值、SOD和POD活性、脯氨酸和可溶性蛋白含量均迅速升高,叶绿素含量、类胡萝卜素含量和叶绿素/类胡萝卜素比值迅速下降。(2)T5处理14d后叶片各生理指标随处理时间的延长与T1处理表现出相同的变化规律(类胡萝卜素和脯氨酸除外),并且分别在T1处理14d和T5处理28d后四季竹叶片全部干枯脱落。(3)随处理时间的延长,T2、T3、T4处理的四季竹叶片各生理指标经过一段时间的适应后最终稳定在处理前水平,且处理间均无显著差异。研究发现,四季竹在土壤相对含水率小于30%的土壤中生长不良,甚至死亡,在相对含水率40%～90%的土壤中能正常生长;四季竹耐受水淹胁迫的时间阈值是28d。

Physiological Adaptation of Oligostachyum lubricum under Water Stress

In order to explore adaptive capacity of Oligostachyum lubricum to different soil water content,we investigated changes of physiological activity in leaves such as ion leakage,MDA content,chlorophyll content,Chl a/Chl b,Chl/Car,SOD activity,POD activity,proline content and soluble protein content in 58-day-experiment.2-year-old O.lubricum seedlings were potted with different soil moisture contents:<30%(T1),40%～50%(T2),60%～70%(T3),80%～90%(T4) of field capacity and root flooding(T5),which were controlled by measuring pot soil water content and watering every day.The result showed that:(1)Ion leakage,MDA content,Chl a/Chl b,SOD activity,POD activity,proline content and soluble protein content increased significantly while chlorophyll content carotenoid content and Chl/Car decreased significantly in treatment T1 with the increase of treated time.(2)The physiological characteristics except carotenoid content and proline content started to change after treated 14 days in treatment T5 in ways that was the same as treatment T1.All leaves became dry and fell off after treated 14 days by T1 and 28 days by T5.(3)All physiological characteristics in treatment T2,T3 and T4 finally stabled at the level before treatment after changing for some days.The results indicated that O.lubricum injured seriously and even die in soil with less than 30% relative moisture content and grew well in soil with 40%～90% relative moisture content.O.lubricum could live for 28 days when root were flooded and would die if root were flooded for more than 28 days.