热激诱导的玉米幼苗耐热性及其与脯氨酸的关系

Heat shock induced heat tolerance in maize seedlings and involvement of proline

关键词:  玉米幼苗  热激  耐热性  脯氨酸  抗氧化酶

Key words:  maize(Zea mays)seedlings  heat shock  heat tolerance  proline  antioxidant enzyme

摘要:

研究了热激对玉米幼苗耐热性的效应及其与脯氨酸的关系。结果表明，培养2.5 d的玉米幼苗经过42 ℃热激4 h并于26.5 ℃下恢复4 h后，提高了玉米幼苗在48 ℃下的存活率，并且热激及其后的恢复过程中都表现出脯氨酸的积累。不同浓度的外源脯氨酸预处理也可提高玉米幼苗内源脯氨酸的水平和抗氧化酶抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)、过氧化物酶(GPX)的活性，从而提高玉米幼苗在高温胁迫下的存活率。这些结果暗示热激过程中脯氨酸的积累所诱发的抗氧化酶活性的增强可能是热激诱导的玉米幼苗耐热性形成的生理基础之一。

Abstract:

Effect of heat shock(HS)on heat tolerance in maize seedlings and its relation to proline(Pro)were studied in this paper. The results showed that HS pretreatment at 42 ℃ for 4 h followed by a 4 h recovery at 26.5 ℃significantly increased survival percentage of maize seedlings under high temperature at 48 ℃，and the procedure of HS and recovery displayed Pro accumulation in maize seedlings. In addition，pretreatment of different concentration exogenous Pro markedly enhanced the level of endogenous Pro and the activities of antioxidant enzyme ascorbic acid peroxidase(APX)，catalase(CAT)，superoxide dismutase(SOD)，glutathione reductase(GR)and peroxidase(POD)in maize seedlings，and improved survival percentage of maize seedlings under high temperature. These results suggested that the increase of antioxidant enzyme activities by HS induced Pro accumulation inducement could be one of the physiological basis in the formation of HS induced heat tolerance in maize seedlings.