作 者 ：李 松,周 磊,郭传龙,陈 奇,陈丽梅*
期 刊 ：西北植物学报 2013年 5期 页码：976~983
关键词：玉米；干旱；气孔开度；质膜H+-ATP酶；过氧化氢；
Keywords:maize, drought, stomatal, plasma membrane H+-ATPase, hydrogen peroxide,
摘 要 ：以白种皮(白玉米)和黄种皮(黄玉米)2个玉米栽培品种为材料,在水培条件下进行聚乙二醇(PEG-6000)模拟干旱胁迫处理,分析玉米叶片抗旱性相关生理特性和质膜H+-ATP酶活性的变化,探讨2种玉米幼苗耐旱性生理机制。结果表明:（1）在2%、5%、10% PEG-6000处理条件下,随处理浓度和时间的增加,2种玉米幼苗植株失水率上升,叶片蒸腾速率降低,气孔传导率下降;在所有相同处理条件下,白玉米植株失水率明显小于黄玉米,而叶片蒸腾速率和气孔传导率下降幅度明显大于黄玉米,即白玉米的耐旱性比黄玉米强。（2）在相同浓度PEG-6000处理下,白玉米叶片可溶性蛋白、可溶性糖含量、游离脯氨酸含量均高于黄玉米,它在干旱胁迫下的渗透调节能力强于黄玉米。（3）在抗氧化酶体系中,随着PEG-6000胁迫浓度的升高,2种玉米叶片CAT活性呈下降趋势,但白玉米CAT活性在2%和5% PEG-6000胁迫下均显著高于黄玉米,其叶片中H2O2含量显著低于黄玉米。（4）随着PEG-6000胁迫浓度的升高,白玉米叶片质膜H+-ATPase磷酸化水平及其与14-3-3蛋白的结合受到的抑制作用比黄玉米强,白玉米叶片质膜H+-ATPase活性比黄玉米叶片低,叶片气孔开度小于黄玉米,叶片蒸腾速率和气孔传导率均低于黄玉米,这可能是白玉米耐旱性强于黄玉米的一个重要机制。
Abstract:Using a white maize(WM) cultivar and a yellow maize(YM) cultivar as the materials,we analyzed the changes in physiological characteristics and activity of plasma membrane(PM) H+-ATPase in the two maize cultivars treated with polyethylene glycol (PEG-6000) simulation drought stress under hydroponic conditions.The results indicated:(1)Under the treatment conditions of 2%,5% and 10% PEG-6000,with an increase in PEG-6000 concentration and treatment time,an elevation in the water loss rate,a decrease in leaf transpiration rate and stomatal conductance were observed in the two maize cultivars.Under all the same treatment conditions,the water loss rate in WM was less than that in YM,whereas,the reduction in leaf transpiration rate and stomatal conductance of WM were larger than those of YM,indicating that drought tolerant of WM was stronger than that of YM.(2)Under the same PEG-6000 treatment conditions,the leaf soluble protein,soluble sugar and free proline contents in WM were higher than those in YM,suggesting that osmotic regulation capacity of WM was larger than that of YM.(3)In the antioxidant enzyme system,with an increase in PEG-6000 stress concentration,CAT activity in both maize leaves display a decreasing pattern.Under 2% and 5% PEG-6000 stress conditions,the CAT activity in WM leaves was still significantly higher than that in YM leaves,which led to a significant lower H2O2 content in WM leaves than that in YM leaves.(4)Under drought stress conditions,the inhibition in the PM H+-ATPase phosphorylation level and its interaction with 14-3-3 protein in WM leaves were stronger than those in YM leaves.The PM H+-ATPase activity in WM leaves was lower than that in YM leaves.Consequently,the stomata aperture in WM leaves was less than that in YM leaves.Leaf transpiration rate and stomatal conductivity in WM were lower than those in YM leaves.This might be an important mechanism underlying the stronger drought tolerance in WM than that in YM.