杂交稻对温度胁迫的抗性与体内活性氧清除剂的关系

THE RELATIONSHIP BETWEEN TEMPERATURE STRESS RESISTANCE AND CHANGES OF THE ENDOGENOUS SCAVENGERS OF ACTIVATED OXYGEN IN HYBRID RICE

本文以低温(1℃)和高温(40℃)处理杂交水稻幼苗后,测定其体内有关生理生化指标的变化。随着温度胁迫时间的延长,幼苗对活性氧清除能力逐渐减弱,丙二醛(MDA)积累增加,膜透性随之增大。MDA在不同杂交稻组合间的增长幅度有差异,但并不与抗温度胁迫能力大小相一致。抗冷性强的'威优287'在低温胁迫后,其电解质外渗率较抗性弱的'威优49'小,超氧物歧化酶(SOD)、过氧化物酶(POX)、过氧化氢酶(CAT)活性及谷光甘肽(GSH)含量则较高,但MDA的积累反而较多。高温对杂交稻幼苗的伤害要比低温小。酶与非酶系统的活性氧清除剂在防御活性氧伤害方面均有重要作用。

The seedlings of hybrid rice were exposed to low(l℃) and high (40℃) temperatures and the permeability of plasma membrane, the activities of SOD, catalase, and peroxidase were assayed and the contents of malondialdehyde (MDA), ascorbic acid and glutathione were estimated. The ability of the seedlings to scavenge activated oxygen progresively decreased with the time of exposure to low temperature, concurrently MDA gradually accumulated and the permeability of the plasma membrane decreased. The amounts of MDA increased were different in the two hybrid combinations and were not in accordance with the ability of cold resistance. Comparing the more resistant variety 'Wei-you 287' with the less resistant variety 'Wei-you 49', it was found that the leakage of electrolytes, the activities of SOD, peroxidase and catalase and the content of glutathione were all higher in the more resistant variety, but the accumulation of MDA was more in the less resistant variety. Higher temperature was less harmful than lower one to the seedlings of hybrid rice. Both enzymic and non-enzymic systems scavenging activated oxygen were similarly important in protecting the seedlings from damage by such oxygen.