褪黑素种子引发处理对干旱胁迫下朝天椒生长与生理特性的影响

Effects of melatonin seed priming on growth and physiological characteristics of Capsicum annuum under drought stress

为探究褪黑素种子引发处理对辣椒耐旱性的调控作用,以茂蔬360为材料,通过盆栽PEG模拟干旱胁迫,分析10种不同浓度褪黑素种子引发处理对朝天椒植株生长及生理特性的影响。结果表明:随着引发液浓度的增加,朝天椒的根长、株高、根冠比、根鲜重、地上部鲜重、地上部干重和根干重呈先上升后下降趋势,浓度为100μmol·L^(-1)时,株高、地上部鲜重和地上部干重达到最大值;褪黑素浓度为75μmol·L^(-1)时,根长、根冠比、根鲜重和根干重达到最大值。生理分析表明,100μmol·L^(-1)褪黑素引发后,干旱胁迫下的植株叶片丙二醛、过氧化氢和超氧阴离子含量最低,可溶性糖、脯氨酸、抗坏血酸(AsA)、脱氢抗坏血酸(DHA)含量和过氧化物酶(POD)、超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性以及根系可溶性蛋白含量最高;75μmol·L^(-1)褪黑素引发后,根系丙二醛、过氧化氢、超氧阴离子含量最低,根系可溶性糖、可溶性蛋白、脯氨酸含量,抗氧化酶(POD、SOD、CAT、APX和GR)活性,AsA、DHA含量和AsA/DHA最高,叶片可溶性蛋白含量、CAT活性和AsA/DHA最高。综上,100μmol·L^(-1)和75μmol·L^(-1)褪黑素引发种子可有效提高朝天椒的耐旱性。

In order to explore the regulatory effect of melatonin seed priming treatment on drought tolerance of pepper,the effects of 10 different concentrations of melatonin seed priming treatment on plant growth and physiological characteristics of pepper were analyzed by pot PEG simulating drought stress with Maoshu 360 as the material.The results showed that the root length,plant height,root-shoot ratio,root fresh weight,shoot fresh weight,shoot dry weight and root dry weight increased firstly and then decreased with the increase of starter solution concentration,and the plant height,shoot fresh weight and shoot dry weight reached the maximum when the concentration was 100μmol·L-1.The root length,root shoot ratio,root fresh weight and root dry weight reached the maximum when the concentration was 75μmol·L^(-1).Physiological analysis showed that the contents of malondialdehyde,hydrogen peroxide and superoxide anion were the lowest,while the contents of soluble sugar,soluble protein,proline,AsA,DHA and antioxidant enzyme activities(POD,SOD,APX and GR)were the highest in leaves under drought stress induced by 100μmol·L^(-1)melatonin.After 75μmol·L^(-1)melatonin,the contents of malondialdehyde,hydrogen peroxide,and superoxide anion were the lowest,and the soluble sugar,soluble protein,proline contents,antioxidant enzymes(POD,SOD,CAT,APX and GR)activities,AsA,DHA contents and AsA/DHA in roots were the highest.The activity of CAT and contents of soluble protein and AsA/DHA in leaves were the highest.These results indicated that 100μmol·L^(-1)and 75μmol·L^(-1)melatonin seed priming treatment was beneficial to improve drought resistance of pepper.