野生稻近等基因系应答低温胁迫的生理生化指标分析

Physiological and biochemical indexes of response to low temperature stress in near isogenic lines of wild rice

关键词:  水稻, 低温胁迫, 生理指标, 丙二醛, 超氧阴离子, 抗氧化酶, 隶属函数

Key words:  rice, low temperature stress, physiological index, malondialdehyde, superoxide anion, antioxidant enzymes, membership function

摘要:

为了解水稻耐冷的生理机制,该文以野生稻近等基因系耐冷水稻品种DC907和其不耐冷受体亲本9311为材料,通过对水稻幼苗低温胁迫处理,检测分析了丙二醛(MDA)、超氧阴离子(O₂^-)、可溶性糖以及抗氧化酶类[超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)]等生理生化指标的变化,并采用隶属函数法综合评价两个品种的耐冷能力。结果表明:(1)O₂^-产生速率、MDA含量和可溶性糖含量都随着低温胁迫时间增加而逐渐升高,在低温胁迫过程中9311的MDA含量和O₂^-产生速率均高于DC907,在低温胁迫后期DC907的可溶性糖含量显著高于9311。(2)在低温胁迫过程中,DC907的抗氧化酶(CAT、POD、SOD和APX等)活性均高于9311,其中CAT、POD随低温胁迫时间增加酶活性增强,SOD和APX随低温胁迫时间增加呈现先降低后升高的趋势。(3)这些生理指标的隶属函数值排序与平均隶属函数值排序一致,说明这些指标与水稻的耐冷性密切相关。从隶属函数值综合评价的结果看出,DC907的耐冷能力比9311强,与大田观测结果相符。

Abstract:

In order to understand the physiological mechanism of cold tolerance in rice, the cold stress treatment of rice seedlings was carried out in a cold-tolerant near-isogenic line DC907 and its cold-tolerant receptor parent 9311 under simulated low temperature environment at 8 ℃ for 1, 3, 5 d. The changes of physiological and biochemical indexes such as malondialdehyde(MDA), superoxide anion(O₂^-), soluble sugar and antioxidant enzymes [superoxide dismutase(SOD), peroxidase(POD), catalase(CAT)and ascorbic acid peroxidase(APX)] during cold stress were detected and analyzed. The cold tolerances of the two varieties were evaluated comprehensively by membership function method. The results were as follows:(1)The rate of O₂^- production, MDA content and soluble sugar content increased with the increase of low temperature stress time, and the contents of MDA and soluble sugar in the process of low temperature stress were significantly different from those in the control group. The content of MDA and O₂^- production rate of 9311 were higher than those of DC907 during low temperature stress, and there were significant differences in MDA contents between the two cultivars at the late stage of low temperature stress. The soluble sugar content of DC907 was significantly higher than that of 9311 at the late stage of low temperature stress.(2)During low temperature stress, the activities of antioxidant enzymes(CAT, POD, SOD and APX)of DC907 were higher than 9311, and the activities of CAT and POD increased with the increase of cold stress time. SOD and APX activities decreased first and then increased with the increase of cold stress time. The results of physiological indexes showed that the cold tolerance of varieties was different. Among them, soluble sugar content, SOD, POD, CAT and APX activities were positively correlated with plant cold tolerance; and the accumulation of MDA and O₂^- was negatively correlated with plant cold tolerance.(3)The order of membership function values of these physiological indicators is consistent with that of average membership function values, which indicates that these indicators are closely related to cold tolerance of rice. According to the result of comprehensive evaluation of membership function value, the cold resistance of DC907 is better than 9311, which is consistent with the field observation results.