《植物生理学报》 2016, 52(8): 1191-1198

外源生长素对镉胁迫下玉米幼苗生长及抗氧化系统的影响

陈晶^1,2, 庞思琪^1,2, 赵秀兰^1,2,*

¹西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆400715; ²重庆市农业资源与环境研究重点实验室, 重庆400716

通信作者：赵秀兰；E-mail: zxl@swu.edu.cn

摘　要：

采用水培试验, 研究了0.5 mg•L^-1 Cd胁迫下添加10 μmol•L^-1吲哚-3-乙酸(IAA)、吲哚丁酸(IBA)和萘乙酸(NAA) 3种外源生长素对玉米幼苗生长、镉吸收、丙二醛(MDA)、脯氨酸(Pro)和谷胱甘肽(GSH)含量及抗氧化酶活性的影响。结果表明, 镉胁迫下, IAA和IBA能显著提高玉米幼苗根和地上部生物量, 显著降低叶片MDA和GSH含量, IAA使玉米幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性显著提高, 但IBA和NAA使上述3种酶活性显著降低。IAA对玉米幼苗根镉含量的影响不显著, 却使地上部镉含量显著降低, IBA使玉米幼苗根和地上部镉含量均显著提高。NAA使玉米幼苗根和地上部的生物量、镉含量、GSH含量和3种酶活性显著降低, 使玉米幼苗叶片MDA显著提高。3种外源生长素均可提高玉米幼苗叶片脯氨酸含量。说明10 μmol•L^-1不同外源生长素对玉米幼苗生长及抗氧化系统的影响不同。IAA和IBA可通过减轻膜脂过氧化程度来缓解镉对玉米幼苗的伤害, 而NAA却加剧了玉米幼苗受到的伤害。相关分析显示, 玉米幼苗叶片MDA含量与3种酶活性及Pro含量的相关性不显著, 但与GSH含量显著相关, 表明GSH在镉胁迫下玉米幼苗抗氧化系统中起作十分重要的作用。

关键词：生长素; 镉胁迫; 玉米幼苗; 抗氧化系统

收稿：2016-03-05   修定：2016-07-16

资助：国家自然科学基金(41471272)。

Effects of exogenous auxins on growth and antioxidation system in maize seedlings under cadmium stress

CHEN Jing^1,2, Pang Si-Qi^1,2, ZHAO Xiu-Lan^1,2,*

¹College of Resources and Environment, Southwest University; Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, China; ²Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China

Corresponding author: ZHAO Xiu-Lan; E-mail: zxl@swu.edu.cn

Abstract:

A hydroponic experiment was carried out to study the effects of exogenous auxins [indole-3-acetic acid (IAA), indole butyric acid (IBA) and naphthalene acetic acid (NAA)] at the concentration of 10 μmol•L^-1 on the growth, cadmium uptake, malondialdehyde (MDA), proline (Pro), glutathione (GSH) and the activities of antioxidant enzymes of maize (Zea mays) seedling under 0.5 mg•L^-1 Cadmium (Cd) stress. The results showed that, under the Cd stress, IAA and IBA significantly increased the biomass of maize seedling, and reduced the contents of MDA and GSH in leaves significantly. Compared with IBA and NAA which decreased the activities of SOD, POD and CAT, IAA significantly improved the activities of these three anti-oxidative enzymes. In IAA treatment, the Cd contents in shoots had been decreased significantly, while showed little change for Cd contents in roots. However, IBA improved the content of Cd in both roots and shoots. In NAA treatment, the biomass, Cd contents, the contents of GSH and the activities of three antioxidant enzymes were all decreased, but the content of MDA was improved. In addition, three exogenous auxins improved the leaves proline content of maize seedlings. These results indicated that the influences of different exogenous auxins on the growth and the antioxidant system of maize seedlings were different under Cd stress. IAA and IBA could alleviate Cd toxicity for maize seedlings by reducing the degree of membrane lipid peroxidation, but NAA intensify the harm of Cd for maize seedlings. Correlation analysis showed that the MDA content of seedling leaves was not significantly correlated to the activity of three enzymes and the content of Pro, but has a significant correlation with GSH content. It is suggested that GSH plays an important role in the antioxidant system of maize seedling under cadmium stress.

Key words: auxin; cadmium stress; maize seedling; antioxidant system