Effects of Exogenous Melatonin on Chlorophyll Metabolism of Soybean under Saline-Alkali Stress
Ma Yue
Ding Xu
Hu Jiachen
Pan Qifeng
Yu Yang
Zhao Qiang
Zhou Wei
Du Jidao
Abstract：Saline-alkali stress(SA)is a kind of common abiotic stress in nature that can inhibit the ab-sorption of water and nutrients by plants,induce plant cells to produce a large number of reactive oxygen spe-cies(ROS),and inhibit plant growth and biomass accumulation.As an active molecule with various regulatory abilities,melatonin(MT)plays the important role in regulating seed germination and plant growth and devel-opment under stresses.In this study,the soybean varieties HH49(with saline-alkali tolerance)and HN95(with saline-alkali sensitivity)were used as experimental materials,and their seedlings were cultured in sa-line-alkali soil(pH=8.78)to V1 stage by potted method.Foliar application of exogenous 300 µmol·L-1 MT was conducted to clarify the effects of MT treatment on chlorophyll metabolism and photosynthetic capacity of soybean leaves under SA.The results showed that compared with the control(CK),SA increased the contents of superoxide anion(O2·-)and hydrogen peroxide(H2O2)in soybean seedling leaves,regulated the expres-sion levels of genes related to chlorophyll(Chl)synthesis and decomposition in soybean seedling leaves,de-creased chlorophyll content and photosynthesis and fluorescence parameters,affected the accumulation and metabolism of carbohydrates,and inhibited plant growth.Exogenous MT treatment significantly increased the activity of antioxidant enzymes in leaves,decreased the ROS accumulation,up-regulated the expression levels of GmGSA2,GmGUN4,GmPORB and GmCHLG genes related to chlorophyll synthesis,down-regulated the ex-pression levels of GmHCAR,GmPPH,GmPAO and GmRCCR genes related to chlorophyll decomposition,in-creased the content of chlorophyll in leaves,improved the photosynthetic capacity of plants,promoted the ac-cumulation and metabolism of soluble sugar,sucrose and starch,and so promoted plant growth of soybean.The results of this study could provide a theoretical basis for breeding saline-tolerant soybean varieties and develo-ping saline-alkali tolerant tillage measures.
Keywords：Soybean(Glycine max L.)MelatoninROS accumulation and removalChlorophyll syn-thesis and decompositionPhotosynthesis
Publication Date：2025-04-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：12( 77-88 )