外源茉莉酸甲酯对镉胁迫下多年生黑麦草种子萌发及幼苗生理的影响

Effects of exogenous methyl jasmonate on seed germination and physiological characteristics of Loliumperenne under cadmium stress

为了探究外源茉莉酸甲酯(MeJA)对镉胁迫下多年生黑麦草(Lolium perenne)种子萌发及幼苗生理特性的影响,以多年生黑麦草品种“夜影”为试验材料,采用不同浓度的外源茉莉酸甲酯(MeJA)对镉胁迫下的黑麦草种子和幼苗进行处理,研究各处理对黑麦草发芽、干物质含量和叶片相对含水量、光合色素含量、活性氧代谢的影响.结果显示,在镉离子浓度为100μmol·L^-1时,多年生黑麦草的生长受到严重抑制;施加MeJA(浓度小于50μmol·L^-1)可以促进多年生黑麦草种子发芽,增加多年生黑麦草幼苗叶绿素含量,促进叶片干物质的积累,增加叶片相对含水量,提高叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,降低游离脯氨酸(Pro)、丙二醛(MDA)、超氧阴离子自由基(O 2·^-)和过氧化氢(H 2O 2)含量.说明低浓度的MeJA可以有效缓解镉胁迫对多年生黑麦草幼苗的伤害;而高浓度的MeJA(大于75μmol·L^-1)则表现出抑制作用,影响多年生黑麦草幼苗的代谢.外源MeJA可促进镉胁迫下多年生黑麦草的发芽和幼苗生长,其效应与MeJA浓度有关.

To investigate the effects of exogenous methyl jasmonate(MeJA)on seed germination and seedling physiological characteristics of perennial ryegrass(Loliumperenne)under cadmium stress,different concentrations of exogenous methyl jasmonate(MeJA)were used to treat the seeds and seedlings of perennial ryegrass under cadmium stress.The germination,dry matter content,relative water content,photosynthetic pigment content and activity oxygen metabolism of perennial ryegrass were studied.The result showed that the growth of perennial ryegrass is severely inhibited when the cadmium ion concentration is 100μmol·L^-1.The application of MeJA(concentration less than 50μmol·L^-1)can promote the germination and increase the photosynthetic pigment content of perennial ryegrass seedlings,promote leaf dry matter content and increase relative water content,the activity of superoxide dismutase,peroxidase,catalase and ascorbate peroxidase are increased and reduced the content of malondialdehyde,proline,O 2·^-and H 2O 2.The low concentration of MeJA could effectively alleviate the damage of cadmium stress.However,high concentration of MeJA(above 75μmol·L^-1)exhibits inhibitory effects on the metabolism of perennial ryegrass seedlings.Exogenous MeJA can promote the germination and seedling growth of perennial ryegrass under cadmium stress and the effects is related to the concentration of MeJA level.