干旱胁迫下不同生态型西瓜叶片抗氧化酶活性及产量分析

Antioxidant enzymes activities in leaves and yield analysis of different ecological types watermelon under drought stress

选取11份不同生态型西瓜品种为研究对象,通过比较它们在旱砂田和正常供水条件下的生理响应,研究开花期不同生态型西瓜叶片抗氧化酶活性等生理特性。结果表明:旱砂田生长环境对西瓜形成较为强烈的干旱胁迫作用,不同生态型西瓜产量均降低,大果形西瓜产量降低幅度为18.6%~35.3%,小果形降低59.7%~67.8%,且品种间存在显著差异。分析认为大果形西瓜抗旱性优于小果形;干旱胁迫下,叶片丙二醛、脯氨酸积累,抗氧化酶SOD、POD、CAT活性增加,表明西瓜对干旱生长环境具有较高的敏感性,但不同生态型西瓜对干旱生长环境的生理响应存在显著差异;大果形西瓜品种脯氨酸含量、SOD、POD、CAT活性增幅较大,分别为83.2%~121.4%、55.2%~75.3%、118.1%~204.4%、52.0%~86.6%,而丙二醛含量增加幅度较小,为13.4%~39.8%;综合比较不同生态型西瓜产量和生理响应差异,认为不同生态型西瓜在旱砂田条件下均有一定的产量形成,且大果形西瓜抗旱性优于小果形,品种(组合)中青9号、NWU-13、陇抗9号、陇抗11号、JY12、津抗5号抗旱性较强,适合旱砂田栽培应用。

The aim of this experiment was to study the relationship between yield and antioxidant enzyme activity in leaves of different ecological types of watermelon during flowering period. Eleven watermelon varieties with different eco-types were grew in gravel - mulched field （water shortage） and normal water supply condition,the malondialdehyde （MDA） , proline content and antioxidant enzymes activity such as superoxide dismutase （SOD） , catalase （CAT） and perox-idase （POD） in leaves were measured. The results showed that there existed marked drought stress in gravel-mulched field, yields of all types of watermelon were decreased, being 1 8 . 6 % -35.3% and 5 9 . 7 % -67.8% in large fruit size and small fruit size, respectively, suggesting that large fruit size possessed stronger drought resistance than that of small one. In addi-tion, there were significant differences among varieties. Under drought stress, MDA, proline content, as well as SOD, POD, CAT activity in leaves were increased, indicating that watermelon was sensitive to drought. Moreover, the response of watermelon to drought were variety dependent. The content of proline, activity of SOD, POD, CAT in large fruit size vari-eties in creased by 83.2% ？121.4%,55.2% ？75.3%,118.1% ？204.4%,52.0% ？86.6%,respectively, the range was greater than that of small fruit size varieties,meanwhile,the content of MDA increased by 13 .4 % -39. 8% ,the range was smaller than that of small fruit size. Taking fruit yield and physiological response into consideration, we argued that all ecotypes of watermelons gained a certain yield level under gravel-mulched conditions, and large fruit watermelon had a stronger drought resistance than small fruit did. Zhongqing9, NWU- 1 3 , Longkang 9, Longkang 11, JY12 and Jinkang 5 had stronger drought resistance, which may be suitable for gravel-mulched field.