低温胁迫对紫花苜蓿生理指标的影响

The effective physiological response and index thresholds of Medicago sativa to low temperature

以俄罗斯杂花苜蓿和3个紫花苜蓿抗寒品系为试验对象,通过0℃,4℃低温胁迫处理,以22℃(室温)为对照,测定3个紫花苜蓿抗寒品系茎、叶的可溶性糖(SS)、游离脯氨酸(FP)、丙二醛(MDA)、可溶性蛋白(SP)的含量和超氧化物歧化酶(SOD)、过氧化氢梅(CAT)、抗坏血酸地氧化物酶(APX)、谷胱甘肽过氧化物酶(GPX)的活性。以明确低温胁迫对紫花苜蓿的生理影响,及各项生理指标变化有效作用阈值与紫花苜蓿抗寒耐受能力的相关程度,筛选出了对紫花苜蓿抗寒性指示作用较敏感的生理指标及其有效作用阈值。结果表明:温度阈值上限SS为0℃,FP为4℃,SP为0℃,MDA为4℃,SOD、CAT、APX及GPX活性低温处理下的变化差异不显著,表明这些生理指标在低温胁迫时反应不敏感。

Used Medicago sativa subsp. varia and three varieties of alfalfa（ Medicago sativa） as the samples,we measured the SOD,CAT,APX and GPX activities in leaf and stem of these alfalfa under low temperature stress in order to select the available and sensitive index,and physiological threshold of SS,FP,SP,and MDA against the stress. The results showed that the upper temperature threshold of SS,FP,SP,MDA was 0℃,4℃,0℃ and 4℃,respectively. There was no significant difference in SOD,CAT,APX and GPX activities between 0℃ and 4℃,indicating that those physiological indexes were not sensitive to low temperature stress.