耐冬和雪椿在不同低温胁迫下的生理响应及抗寒性研究

Physiological response and cold resistance of C. japonica‘Naidong'and C. japonica var. decumbens under different low temperature stress

以耐冬和雪椿为材料,通过自然低温(2013年10月—2014年01月)和人工气候室控制低温(4、0、-4、-8、-12℃)2种处理方法,测定低温过程中样本叶片生理生化指标的变化,结合低温半致死温度和隶属函数的综合评价,探讨耐冬和雪椿的抗寒性及其生理响应机制。结果表明,耐冬和雪椿叶片中各物质的变化规律基本相似,随着低温胁迫的加剧,耐冬的叶绿素含量始终高于雪椿,且自然胁迫波动性较大;可溶性蛋白、POD酶活性和CAT酶活性均是先下降,当达到一定阈值后开始上升。但耐冬和雪椿生理指标的阈值存在差异,耐冬可溶性蛋白和POD酶活性在-8℃低温处理后开始上升,雪椿的可溶性蛋白和POD酶活性都在0℃低温处理后开始上升,而耐冬和雪椿的CAT酶活性都在4℃低温处理后就开始上升。经自然低温处理后耐冬的低温半致死温度为-14.08℃,雪椿的为-11.93℃,结合隶属函数综合评价,判定耐冬的耐寒性优于雪椿。

The physiological and biochemical indexes such as chlorophyll,soluble protein,proline,POD,SOD,CAT and MDA were measured to analyze the cold tolerance differences in Camellia species of C.japonica‘Naidong’and C.japonica var.decumbens,under natural low temperatures in Zhengzhou(during Oct.2013 to Jan.2014)and the artificially controlled low temperature stress(4,0,-4,-8,-12℃)in climate chamber,separately.Low semi-lethal temperature(LT 50)were calculated using logistic equation and the cold resistance was comprehensively evaluated using subordinate function method in C.japonica‘Naidong’and C.japonica var.decumbens.The results show that the change rule of these substances was similar.With the increase of low temperature stress,the content of chlorophyll in C.japonica‘Naidong’was always higher than that in C.japonica var.decumbens,and the natural stress of C.japonica‘Naidong’was more volatile.The soluble protein,POD activity and CAT activity decreased first,then increased after reaching a certain threshold.But the thresholds of physiological indexes had differences between the two species of Camellia.The soluble protein and POD activity of C.japonica‘Naidong’began to rise by-8℃treatment,but the soluble protein and POD activity of C.japonica var.decumbens began to rise by 0℃treatment.The CAT activity of both began to rise by 4℃treatment.After natural low temperature treatment,the LT 50 of C.japonica‘Naidong’was-14.08℃,while that of C.japonica var.decumbens was-11.93℃.Combined with the comprehensive evaluation using subordinate function method,the cold resistance of C.japonica‘Naidong’was better than that of C.japonica var.decumbens.