Effects of Salt and Drought Stresses on Growth and Photosynthetic Characteristics of Different Soybean Varieties(Lines)

Li Siqi; Du Yanli; Hu Aibo; Liu Yan; Song Guoqing; Du Jidao

doi:10.14083/j.issn.1001-4942.2024.11.005

Abstract：In order to determine the effects of salt stress,drought stress and their combination on growth and photosynthetic characteristics of different soybean(Glycine max L.)varieties(lines),7 soybean varieties(lines)were used as materials,and the pot experiment was conducted by setting four treatments including control(CK,normal water supply,75％of maximum field water capacity),salt stress(S,0.44％of soil salt content),drought stress(D,35％of maximum field water capacity)and salt-drought combined stress(S+D,35％of maximum field water capacity,0.44％of soil salt content).The effects of different treatments on 31 in-dicators of soybean seedlings such as growth parameters,photosynthetic characteristics,chlorophyll content,chlorophyll fluorescence parameters and root configuration were studied.The results showed that compared with CK,the digital biomass,leaf area,normalized vegetation index,leaf chlorophyll content,and some chloro-phyll fluorescence parameters including Fm,Fv/Fm,Fv/Fo,ΦPS Ⅱ,ETR and NPQ of soybean seedlings were significantly reduced under S and S+D treatments,especially under S+D treatment.Drought stress signif-icantly increased the leaf angle value and leaf projection area of soybean seedlings.The three stress treatments significantly reduced total root length,root surface area,root volume,root tip number,root bifurcation num-ber,cross number,photosynthetic rate,stomatal conductance,intercellular CO2 concentration and transpira-tion rate of soybean seedlings,and most of these indicators decreased to a significant level,but the reduction range under drought stress treatment was smaller than that under salt stress and their combination.In conclu-sion,the effects of salt and drought combined stress on soybean seedling growth were the most obvious,fol-lowed by salt stress and drought stress in order.According to the results of principal component analysis and membership function comprehensive evaluation,21C49 was a salt-tolerant line,Mengdou 46 was a variety re-sistant to drought stress and salt-drought combined stress,Heike 68 was a salt-sensitive and drought-sensitive variety,and Longken 330 was a variety sensitive to salt-drought combined stress.