苔景天和联合勘察加景天对低温胁迫的生理响应

目的]多种景天类植物具有极强的抗寒性,但对其抗寒机理了解较少.通过检测低温胁迫下不同景天植物的生理指标,研究抗寒性差异的原因,探索景天抗寒机理.方法]以抗寒性强的苔景天(Sedum acre)和抗寒性较弱的联合勘察加景天(S.kamtschaticum Subsp.ellacombianum)为实验材料,经过人工低温处理(10、5、0、-5、-10℃五个梯度),检测两种景天叶片中相对含水量、可溶性蛋白、可溶性糖、淀粉及过氧化氢酶和超氧化物歧化酶活性等生理指标.结果]经低温处理后,两种景天的相对含水量、淀粉含量均降低,可溶性糖含量升高,而可溶性蛋白含量在苔景天中表现出升高的趋势,但在联合勘察加景天中则降低.对于以上生理指标,苔景天均明显高于联合勘察加景天.在联合勘察加景天中,低温诱导了CAT、SOD活性的升高,而在苔景天CAT活性出现了降低,SOD活性虽也被诱导升高,但显著低于联合勘察加景天.结论]抗寒性不同景天对低温的生理响应存在显著差异.

The Physiological Response of Sedum acre Plant and S.kamtschaticum Subsp.ellacombianum Plant to Low Temperature

Objective]Many sedum plants showed strong cold resistance,but the mechanism is little known.In this study,the physiological indices of different sedum plants in response to low temperature were tested to investigate the reason leading to the difference of cold resistance,and to explore the cold resistance mechanism of Sedum plants.Method]The Sedum acre cuttings(high cold resistance) and the S. kamtschatieum Subsp.ellacombianum cuttings(relatively low cold resistance) were treated by five levels of low temperatures(10,5,0,-5 and - 10℃).Then the relative water content,soluble protein content,soluble sugar content,starch content,and the activities of catalase(CAT) and super oxide dismutase(SOD) were tested as well.Result]The results showed that after treatment with low temperature,the relative water content and starch content decreased,and the soluble sugar content increased in these two Sedum plants.The soluble protein content in Sedum acre cuttings was enhanced,but was reduced in S.kamtschaticum Subsp. ellacombianum cuttings.These physiological indices above in Sedum acre cuttings were visibly higher than those in 5.kamtschaticum Subsp.ellacon(?)mm cuttings.In S.kamtschatieum Subsp.ellacombianum cuttings,low temperature increased the activities of CAT and SOD,but in Sedum acre cuttings the activity of CAT decreased.And though induced to rise by low temperature in sedum acre cuttings,the SOD activity was significantly lower than that in S.kamtschaticum Subsp.ellacombianum cuttings.Conclusion]Significant difference was found in the physiological response to low temperature between these two Sedum plants.The reason in Sedum plants that leads to the cold resistance at the physiological level need to be examined in the future study.