水稻幼苗对干旱和高温交叉逆境的适应机制研究

Studies on the Adaptive Mechanism of Rice Seedlings under the Cross Stress of Drought and High Temperature

利用水培的方法,通过比较水稻幼苗在干旱、高温单一和交叉逆境下渗透调节物质含量和活性氧清除系统的变化,研究了水稻幼苗对干旱和高温交叉逆境的适应机制。结果表明,与对照相比,高温、干旱单一逆境下,水稻幼苗可溶性糖含量、脯氨酸含量、相对电导率、O-2.产生速率和H2O2含量均显著提高,保护酶(SOD、POD、CAT)活性和GSH、ASA含量显著降低;与单一逆境处理相比,交叉逆境处理可溶性糖、脯氨酸含量进一步提高,而相对电导率、O-2.产生速率和H2O2含量降低,保护酶活性和GSH、ASA提高。说明逆境预处理可通过促进水稻叶片渗透调节物质的积累,提高活性氧的清除能力,进而增强水稻幼苗对其它逆境的适应能力。

The mechanism of adaptability to the cross stress of drought and high temperature of rice was studied by comparing the changes of the contents of osmotic regulation substances and the active oxygen removal system of rice seedlings under the stress of drought or high temperature and the cross stress of them in water culture. The results showed that the soluable sugar content,proline content,relative conductivity,O-2.production rate and H2O2 content were significantly increased while the activity of protective enzymes（ SOD,POD and CAT） and the contents of GSH and ASA were significantly decreased after the treatment of high temperature or drought. The treatments with cross stress of drought and high temperature showed higher contents of soluble sugar,proline,GSH and ASA and activity of protect enzymes but lower relative conductivity,O-2.production rate and H2O2 content than those with only stress of drought or high temperature,indicating the pretreatment of a stress would improve rice seedlings in the resistance to another stress through promoting the accumulation of osmotic regulation substances and enhancing the capacity of scavenging active oxygen in rice leaf.