乙烯对棉花适应淹水胁迫的作用及其机制

Effects of Ethylene on Cotton Adaption to Waterlogging Stress and the Underlying Mechanism

【目的】淹水胁迫影响棉花生长发育,持续淹水可导致棉花减产甚至绝产,增强棉花适应淹水胁迫的能力对棉花抗涝夺丰收至关重要。乙烯(Ethylene)是备受关注的重要信号分子,在植物抗逆过程中发挥着重要作用,但在缓解棉花淹涝伤害中作用和机制尚不清楚。本文以棉花(Gossypium hirsutum L.)品种K638为材料,在山东棉花研究中心试验站(山东临清)的田间电动遮雨棚内,对盛花期棉花淹水处理10 d,通过叶面喷施乙烯信号通路抑制剂1-甲基环丙烯(1-methylcyclopropene,1-MCP)或乙烯合成前体1-氨基环丙烷-1-羧酸(1-Aminocyclopropane-1-carboxylic acid,ACC)抑制或促进棉株体内乙烯合成,探究了乙烯含量对棉花适应淹水胁迫的作用及其生理机制。结果表明,与未喷施的淹水处理相比,喷施1-MCP乙烯含量降低了5.3%,丙二醛(Malondialdehyde,MDA)、厌氧代谢酶乙醇脱氢酶(Alcohol dehydrogenase,ADH)、丙酮酸脱羧酶(Pyruvate decarboxylase,PDC)和乳酸脱氢酶(Lactate dehydrogenase,LDH)分别降低了39.2%、37.8%、20.5%和8.2%,主茎功能叶光合速率和单株干物质质量分别提高了13.5%和3.3%,籽棉产量提高了4.6%;而ACC的效果相反,喷施ACC促进受淹棉株体内乙烯积累,乙烯含量升高了8.0%,MDA、ADH、PDC和LDH分别增加了19.5%、17.5%、11.2%和8.0%,光合速率和单株干物质质量分别降低了6.0%和7.7%,籽棉产量减少了8.0%。由此可见,降低棉株体内乙烯含量,可显著降低活性氧对细胞膜的损伤,抑制厌氧代谢有毒产物的积累,减轻淹水胁迫下棉花所受的低氧损伤,缓解受淹棉株光合生产和生长发育的受抑制程度,一定程度上缓解了淹水胁迫造成的伤害,是提高棉花适应淹水胁迫的重要途径。

[Objective]Waterlogging adversely affects cotton growth and development,and continuous waterlogging may further result in considerable yield loss or crop failure.Enhancing the ability of cotton to adapt to waterlogging stress to preserve yield and quality is therefore critical.Ethylene is an important signal molecule,which plays a vital role in the process of plant stress resistance.However,the mechanism of ethylene in mitigating cotton waterlogging damage is still unclear.[Method]In this study,we setup an experiment with a cotton(Gossypium hirsutum L.)variety K638 in an electric rain shelter at the experimental station of the Shandong Cotton Research Center at Linqing,Shandong.We treated the cotton plants by waterlogging for 10 d during the flowering stage and used a non-waterlogged treatment as the control.During the waterlogging stress treatment,cotton plants were treated with an ethylene signal transduction inhibitor(1-MCP)or ethylene synthesis precursor(ACC)to detect the effects of ethylene content on cotton waterlogging injury and its physiological mechanism.[Result]The results revealed that a foliar spray of 1-MCP significantly inhibited ethylene synthesis in the stressed cotton plants,the content of ethylene and malondialdehyde(MDA)decreased by 5.3%and 39.2%,and the activities of alcohol dehydrogenase(ADH),pyruvate decarboxylase(PDC),and lactate dehydrogenase(LDH)decreased by 37.8%,20.5%,and 8.2%,respectively.The photosynthetic rate,dry weight of the whole plant,and seed cotton yield increased by 13.5%,3.3%,and 4.6%,respectively.The effect of ACC on the plants was the opposite because spraying ACC promoted ethylene accumulation in the waterlogged cotton.The ethylene and MDA content increased by 8.0%and 19.5%,respectively.The activities of ADH,PDC,and LDH increased by17.5%,11.2%,and 8.0%,respectively,while the photosynthetic rate,dry weight of the whole plant,and seed cotton yield decreased by 6.0%,7.7%,and 8.0%,respectively.[Conclusion]In summary,reducing ethylene content in waterlogged cotton plants can significantly alleviate hypoxia damage caused by waterlogging stress and subsequently promote cotton growth and development by restoring physiological metabolism.