外源甲基乙二醛(MG)对盐胁迫下板栗幼苗生理特性的影响

Effect of Exogenous Methylglyoxal(MG)on Physiological Characteristics of Chestnut Seedlings under Salt Stress

甲基乙二醛(MG)为近年来发现的新兴信号分子,在调控植物发育和抗逆过程中具有重要作用。为了探讨MG缓解盐胁迫对板栗幼苗损伤的生理机制,以板栗品种‘蒙早’2 a生幼苗为试验对象,研究了施用0.5 mmol/L MG及其清除剂N-乙酰半胱氨酸(NAC)对盐胁迫(NaCl含量200 mmol/L)下板栗幼苗抗氧化系统、乙二醛酶系统和渗透调节物质含量的影响。结果表明:施用外源MG能够提高盐胁迫下板栗幼苗抗氧化酶(SOD、POD、CAT、APX、GR)的活性,激活乙二醛酶系统(GlyI和GlyII酶活性提高),调节AsA—GSH循环,增加抗氧化剂(GSH、AsA)含量以及渗透调节物质脯氨酸(Pro)在叶片中的积累,减少丙二醛(MDA)、MG和超氧阴离子(O2-)的积累,缓解盐胁迫下板栗幼苗遭受的MG胁迫、氧化胁迫和渗透胁迫伤害,增强板栗幼苗的耐盐性;而添加MG清除剂NAC后,抑制了MG的缓解损伤效应。MG对增强板栗的耐盐性具有积极作用,研究MG作为新型外源调节物质调控植物抗逆胁迫为拓展板栗适用范围和盐碱地区板栗资源挖掘提供了重要的理论依据。

Methylglyoxal(MG)is a newly discovered signaling molecule that plays an important role in regulating plant development and stress resistance processes.In order to explore the physiological mechanism of MG alleviating salt stress damage to chestnut seedlings,the effects of 0.5 mmol/L MG and its scavenger N-acetylcysteine(NAC)on the antioxidant system,glyoxase system,and osmoregulatory substance content of chestnut seedlings under salt stress(NaCl content of 200 mmol/L)were studied in the 2-year-old seedlings of the chestnut variety Mengzao.The results showed that the application of exogenous MG could increase the activity of antioxidant enzymes(SOD,POD,CAT,APX and GR)in chestnut seedlings under salt stress,activate the glyoxase system(GlyI and GlyII enzyme activities increased),regulate the AsA-GSH cycle,increase the content of antioxidants(GSH and AsA),and the accumulation of osmotic regulator proline(Pro)in leaves,while reduce the accumulation of malondialdehyde(MDA),MG,and superoxide anion(O2-),relieve the damage caused by MG stress,oxidative stress,and osmotic stress on chestnut seedlings under salt stress,and enhance the salt tolerance of chestnut seedlings.After adding the MG scavenger NAC,the alleviating effect of MG was inhibited.MG has a positive effect on enhancing the salt tolerance of chestnut.Studying MG as a new exogenous regulatory substance to regulate plant stress resistance provides important theoretical basis for expanding the applicability of chestnut and exploring chestnut resources in saline alkali areas.