油菜素内酯对干旱胁迫下羊草渗透调节及抗氧化酶的影响研究

受全球气候变化影响,我国牧区干旱现象日益严重,极大限制了草原生产力的提高。本文采用盆栽人工控水的方法,研究不同浓度油菜素内酯(BR)处理对羊草生长和抗旱特性的影响。结果表明干旱显著抑制植株的生长,而BR能有效减缓干旱胁迫对羊草造成的伤害。经过不同浓度的BR处理后,与干旱胁迫相比,株高、叶面积、干重、含水量、叶绿素a、叶绿素b、类胡萝卜素、根系活力、脯氨酸、可溶性蛋白、可溶性糖和5种抗氧化酶活性均随浓度增加而升高,但高浓度下又有降低的趋势,而丙二醛(MDA)和叶片电导率则相反,其中以BR浓度为0.1 mg/L时的抗旱效果最好。研究发现适当浓度的BR提高羊草株高、叶面积和光合色素含量,促进干物质积累和根系活力,与其降低膜脂过氧化产物MDA与质膜透性,提高脯氨酸、可溶性蛋白、可溶性糖等渗透调节物质含量,增强超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)等抗氧化酶活性密切相关。

Effects of brassinosteroid application on osmotic adjustment and antioxidant enzymes in Leymus chinensis under drought stress

Droughts have become increasingly severe in pastoral areas of China and have greatly constrained the productivity of grassland.The influence of brassinosteroids(BR)on the growth and drought tolerance of Ley-mus chinensis has been studied under controlled soil and water conditions using a pot experiment design.The results showed that drought stress substantially disrupted plant growth and development but that BR could ef-fectively alleviate this damage.The most effective concentration of BR was 0.1 mg/L.Plant height,leaf area, dry weight,water content,chlorophyll a,chlorophyll b,carotenoids,root activity,proline,soluble protein,
soluble sugar and 5 kinds of enzyme activity increased with all BR concentrations except for the highest concen-tration level.BR decreased malondialdehyde (MDA)content and leaf electrical conductivity.The optimal con-centration of BR increased the content of photosynthetic pigment and promoted the accumulation of dry matter and root activity compared to the drought control.These changes might be closely related to the decrease of membrane lipid peroxidation production,MDA content and membrane permeability.Also significant may be the increase of osmotic adjustment substances such as proline,soluble protein,soluble sugar,and the enhance-ment of antioxidase activities such as superoxide dismutase,catalase,peroxidase,ascorbate peroxidase and glu-tathione reductase.