Improved drought tolerance by early IAA- and ABA-dependent H_lus-plus">2O_lus-plus">2 accumulation induced by α-naphthaleneacetic acid in soybean plants

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• 作者：Xinghua Xing ; Hongqiang Jiang ; Qin Zhou ; Han Xing ; Haidong Jiang…
• 关键词：IAA ; ABA ; H2O2 ; Antioxidant enzymes ; Drought ; NAA ; Soybean
• 刊名：Plant Growth Regulation
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：80
• 期：3
• 页码：303-314
• 全文大小：872 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Physiology
  
• 出版者：Springer Netherlands
• ISSN：1573-5087
• 卷排序：80

文摘

α-Naphthaleneacetic acid (NAA), a synthetic auxin, improves plant stress tolerance. A hydroponic experiment was carried out to investigate how NAA pretreatment could improve drought resistance in soybean seedlings. NAA pretreatment triggered an early increase in hydrogen peroxide (H₂O₂), indole-3-acetic acid (IAA) and abscisic acid (ABA), a late elevation of net photosynthetic rate (Pn), a late decrease in malondialdehyde (MDA) and electrolyte leakage and a rise in antioxidant enzyme activities during both early and late phases, under drought stress. However, the application of the ABA biosynthesis inhibitor tungstate and the IAA biosynthesis inhibitors l-Amino-oxyphenylpropionic acid and aminoethoxyvinylglycine resulted in an early decrease in H₂O₂ and an early and late decline in the activities of antioxidant enzymes in NAA-pretreated stressed plants. Moreover, the inhibitors also induced an increase in H₂O₂, MDA and electrolyte leakage and decrease in Pn in the late phase in stressed leaves pretreated with NAA. Similarly, the application of the NADPH oxidase inhibitor diphenyleneiodonium and H₂O₂ scavenger dimethylthiourea arrested the early accumulation of H₂O₂, but not of IAA and ABA in stressed plants pretreated with NAA, and blocked the early and late rise in antioxidant enzyme activities, the late increase in Pn and the late decrease in H₂O₂, MDA and electrolyte leakage induced by NAA in drought-stressed plants. Our data suggest that NAA application triggers early IAA- and ABA-dependent H₂O₂ accumulation, which, in turn, results in an enhancement of antioxidant capacity and drought stress tolerance in soybean seedlings.