低温、乙烯逆境下的番茄NR基因表达及相关反应

Expression of NR gene and related responses under ethylene and chill in tomato

通过低温和乙烯逆境下番茄植株的生长表现和抗性生理指标的变化及乙烯受体蛋白基因NR的表达 ,研究了NR基因与低温和乙烯的关系。结果显示 :低温 ( 5℃ )抑制了NR基因的表达 ,维持了细胞膜的完整性 ,并减轻和延缓番茄实生苗因乙烯胁迫所产生的黄化、衰老等症状 ;外源乙烯增加植株细胞膜透性 ,处理的时间越长、细胞膜透性增加得越多 ,但低温可以推迟这一进程 ;低温和乙烯都可显著增加植株叶片蒸腾作用、呼吸作用和气孔导度 ;在有和无外源乙烯时 ,低温和乙烯抑制剂Ag+均抑制番茄NR基因的表达。因此认为低温抑制了NR基因的表达 ,降低了植物对乙烯的敏感性 ,减轻和延缓了因胁迫乙烯的产生而造成的伤害 ;而抑制NR基因的表达 ,能提高植物的抗逆性 ;NR基因是乙烯和低温胁迫症状的正调节因子。

The relations of NR gene, ethylene and low temperature were studied by the changes of growth, physiology and expression of NR gene of tomato seedlings under chill and stress of ethylene. The result showed that chilling temperature(5℃)restrained expression of NR gene, maintained intact cytomemebrane, lessened and delayed symptom of chlorosis and senescence in tomato seedling. Exogenous ethylene increased plant cytomemebrane permeability and the longer ethylene treated , the more permeability was, but chill postponed the process. The result also showed that ethylene and chilling treatment significantly enhanced the transpiration rate, respiration and stomatal conductance of plant leaves. Chill and Ag + restrained expression of NR gene either with or without ethylene. Hence, restraint of NR expression in low temperature (5℃)may be the reason that plant reduced both its sensibility to ethylene and its damage caused by stress ethylene. Restraining expression of NR may improve plant resistance. NR gene demonstrated as a positive factor regulating plant in a stress condition.