PEG胁迫下褪黑素对生菜幼苗形态和生理特性的影响  

Effects of Melatonin on Seedlings Morphology and Physiological Characteristics of Lettuce Under PEG Stress

作　　者：张盼盼[1,2] 高研 王小林 刘育仁 梁喜龙 张雄 ZHANG Panpan;GAO Yan;WANG Xiaolin;LIU Yuren;LIANG Xilong;ZHANG Xiong(College of Life Science,Yulin University,Yulin,Shanxi 719000;Heilongjiang Province Engineering&Technology Research Center of Plant Growth Regulation,Daqing,Heilongjiang 163316)

机构地区：[1]榆林学院生命科学学院,陕西榆林719000 [2]黑龙江省植物生长调节剂工程技术研究中心,黑龙江大庆163316

出　　处：《北方园艺》2022年第10期1-8,共8页Northern Horticulture

基　　金：国家自然科学基金资助项目(31860340);陕西省自然科学基础研究计划资助项目(2020JQ-902);陕西省产业技术体系资助项目(2021);榆林市科技局科技计划资助项目(2018-cxy-2);榆林学院引进人才科研启动资助项目(17GK21)。

摘　　要：以‘奥跃生菜’为试材,采用盆栽法,设置正常浇灌营养液(对照,CK)、根系浇灌含有100μmol·L^(-1)褪黑素的营养液(MT)、根系浇灌含有25%PEG的营养液(D)和25%PEG的营养液+根系浇灌含有100μmol·L^(-1)褪黑素的营养液(D+MT)4个处理,研究了PEG胁迫下褪黑素对生菜幼苗生长和生理特性的影响,以期为褪黑素在生菜中抗旱栽培的应用提供参考依据。结果表明:干旱胁迫下根施褪黑素生菜幼苗总根长、根体积、根表面积、根平均直径、地上地下部分干质量、根冠比、叶绿素相对含量显著增加(P<0.05),叶片相对含水量也呈增加趋势,但差异不显著;同时干旱胁迫下褪黑素增加了生菜叶片实际光化学效率和光化学淬灭系数,降低了叶片PSⅡ的非光化学淬灭系数;除根系过氧化物酶(POD)活性外,干旱胁迫下根施褪黑素幼苗叶片和根系超氧化物歧化酶(SOD)活性、POD活性、可溶性蛋白质含量均升高;而丙二醛(MDA)含量下降;其中SOD活性差异在叶片和根系中均达显著水平(P<0.05)。因此,根施100μmol·L^(-1)褪黑素能够通过调控生菜幼苗形态特征,增强根系和叶片保护酶活性和可溶性蛋白质含量,提高生菜叶片光合指标,来缓解生菜在干旱条件下受到的胁迫作用。‘Aoyue lettuce’was used as the experimental material.The potted method was adopted,four treatments were set up including the nutrient solution(CK),the nutrient solution containing 100μmol·L^(-1) melatonin(MT),the nutrient solution containing 25%PEG(D)and 25%PEG nutrient solution+root irrigation nutrient solution contained 100μmol·L^(-1) melatonin(D+MT),and the effects of melatonin on the growth and physiological characteristics of lettuce seedlings under PEG stress were studied,in order to provide reference for drought-resistant cultivation of melatonin in lettuce.The results showed that root length,root volume,root area,average root diameter,aboveground and underground dry weight and root-shoot ratio of melatonin applied lettuce seedlings were significantly increased in melatonin applied to roots under drought stress(P<0.05),leaf relative water content also increased,but the difference was not significant.Melatonin increased the actual photochemical efficiency and photochemical quenching coefficient of the photosystemⅡof lettuce leaves,and decreased the non-photochemical quenching coefficient of PS components in leavesunder drought stress.In addition to root peroxidase(POD)activity,superoxide dismutase(SOD)activity,peroxidase(POD)activity and soluble protein content in leaves and roots were increased by melatonin under drought stress,but malondialdehyde(MDA)contentin leaves and roots decreased.SOD activity in roots and leaves was significantly different between D and D+MT(P<0.05).Therefore,root application of 100μmol·L^(-1) melatonin can regulate the morphological characteristics of lettuce seedlings,enhance the activities of protective enzymes and soluble protein content in roots and leaves,and improve photosynthetic index of lettuce leaves,alleviating the stress of lettuce under drought conditions,thus providing theoretical basis for high yield cultivation of lettuce.

关 键 词：生菜 褪黑素 干旱胁迫 形态 生理特征 

分 类 号：S636.2[农业科学—蔬菜学]