不同耐旱性玉米杂交种及其亲本叶片活性氧代谢对水分胁迫的响应

Response of activated oxygen metabolism to water stress in different drought-tolerant maize hybrids and their parents

干旱是制约玉米生产最主要的逆境因子。通过在活动式防雨棚下进行盆栽试验,以耐旱性不同的2个玉米杂交种及其亲本自交系为材料,研究了水分胁迫下玉米叶片活性氧代谢的变化及膜脂过氧化水平。结果表明,在水分胁迫下:(1)玉米叶片O 2-产生速率和H2O2含量升高、活性氧清除酶类SOD、CAT、AsP活性和清除剂AsA含量在生育前期略微升高,在生育后期明显降低,致使膜脂过氧化产物MDA含量在整个生育期,特别在生育后期明显升高;(2)耐旱性不同的玉米材料维持活性氧代谢平衡的能力存在差异,且该差异在生育后期更为明显。耐旱性较强的掖单2号及其亲本叶片O 2-产生速率和H2O2含量增加幅度小,生育前期SOD、CAT和AsP活性,以及AsA含量增幅大,后期清除酶活性和清除剂含量较高,全生育期内MDA含量增幅小,表现出较强的维持活性氧代谢平衡能力。而耐旱性较弱的掖单13及其亲本正相反;(3)杂交种维持活性氧代谢平衡的能力受亲本维持能力遗传决定。杂交种各指标的相对耐旱值与其两亲本的平均值呈正相关,其中CAT和AsP活性以及AsA含量3个指标差异达显著水平。

Drought might be the biggest adversity in the nature and might seriously affect maize （ Zea Mays L. ）, one of the most important food-feedstuff crops in China. Although ecologists and physiologists have focused on the response of the activated oxygen metabolism to water stress in maize for a long period and made a great progress, the changes of activated oxygen metabolism, under water stress, and the relationship between the hybrid＇ s and its parents＇ ability to maintain the balance of activated oxygen metabolism in different drought-tolerant maize during the whole life are still lacking. A pot-cultivation experiment, therefore, was conducted in the waterproof shed to try to explore these issues. Different drought-tolerant maize hybrids, Yedan 2, Yedan 13 and their parents were used in the experiment. The result showed that under water stress ： （ 1 ） The O2 production rate and the content of H2O2 in maize leaves increased rapidly, whereas the activities of SOD, CAT, ASP, and the content of ASA were increased a little in the early growing stage and decreased obviously in the late growing stage. Consequently the content of MDA, the outcome of lipid peroxidation, was much higher in the whole life period, especially in the late stage. （2） There was a difference in the ability to maintain the balance of activated oxygen metabolism between different drought-tolerant maize hybrids, and much more difference was found in the late period. The high drought-tolerant maize, Yedan 2 and its parents, showed a higher ability to maintain the balance of activated oxygen metabolism. In Yedan 2 and its parents, the increase in the O2 production rate and the content of H2O2 in maize leaves was less, accompanied by a much more increase in the activities of SOD, CAT and ASP, and in the content of ASA in the early stage, a much more increase in the enzymes＇ activity and the content of scavengers in the late stage, and a smaller increase in the content of MDA during the whole life period. The changes were to the contrary in Yedan 13 and its parents whose drought-tolerance was low. （3）The hybrid＇s ability to maintain the balance of activated oxygen metabolism was decided genetically by that of its parents. There was a positive correlation in WS/CK ratio between the hybrid and the averages of its parents. Moreover, the correlation was significant in terms of CAT, ASP, and ASA.