低温离体胁迫对牛角瓜细胞质膜透性的影响

Effect of Low Temperature Stress on Cell Membrane Permeability of in Vitro Calotropis gigantea

为了研究牛角瓜(Calotropis gigantea)植株在低温胁迫下细胞质膜透性的变化,将其成年植株的离体根、茎、叶置于不同的低温(10、5、0、-5℃)条件下处理1、4、8、18、24 h,室温(25℃)放置相同时间的为对照,测定分析电解质渗出率。结果表明:在相同处理条件下,牛角瓜植株根、茎、叶3种器官的细胞质膜透性存在一定的差异;所试验的胁迫温度电解质渗出率均明显高于对照,时间处理、温度处理以及两者间的交互作用,对牛角瓜的根、茎、叶3个植株部位的电解质渗出率均有极显著的影响;处理温度低于5℃时,电解质渗出率均急剧上升至差异显著水平;-5℃处理超过4 h,电解质渗出率基本达到90%以上,接近饱和状态,持续低温处理对其影响不大;在相同处理条件下,牛角瓜根的电解质渗出率比茎、叶的大,其抗寒性相对较差;初步判断牛角瓜植株对低温耐受的敏感温度临界值为5℃。

In order to study the change of cell membrane permeability under low temperature stress, the plant roots, branches and leaves of in vitro Calotropis gigantea were exposed at 10 ℃, 5 ℃, 0 ℃ and -5 ℃ temperature for 1 h, 4 h, 8 h, 18 h, 24 h with the room temperature （25 ℃） as the control to determine the electrolyte leakage rate. Results showed that there were differences in the membrane permeability of the roots, branches and leaves of C. gigantea in the same treatment. The electrolyte leakage rate with the stress temperature was significantly higher than that of the control group, and there were extremely significant effects on the roots, branches and leaves under the different time, temperature and their interaction. The electMyte leakage rate rose sharply to the significant level of difference when the temperature was below 5 ℃. When treat- ed at -5 ℃ for more than 4 h, it could reach over 90% and closed to the saturated state. Continuous low tem- perature treatment had little effect on it. The cold resistance of roots was relatively poor because its electrolyte leakage rate was larger than that of branches and leaves under the same condition. It was preliminarily conclud- ed that the sensitive temperature threshold of low temperature tolerance of C. gigantea was 5 ℃.