Response Of Different Maize Inbred Lines To Salt Stress And Its Salt Tolerance

In order to study the response of maize inbred lines under salt stress,provide the theoretical basis for the adaptability cultivation of Maize in saline alkali soil and the evaluation of salt tolerance in Ningxia,the salt-tolerant materials were screened and the salt-tolerant identification technology system was constructed.In this study,maize inbred lines from different regions were used as materials,and the responses of maize inbred lines to salt stress were studied by means of laboratory simulation salt stress,pot culture and field experiment.The germination rate,germination potential,salt damage rate,salt tolerance index,plant height,stem diameter,leaf area,biomass,membrane permeability and MDA,changes of photosynthetic parameters,yield and yield components under salt stress were measured,and the response of maize inbred lines to salt stress was revealed.Based on the above research,through the comparison of three identification methods,the technical system of salt tolerance identification of maize was constructed,and the salt-tolerant materials were screened.The main findings are as follows:1.The results of laboratory simulation of salt stress test showed that salt stress can inhibit the germination of maize inbred lines,based on the comprehensive analysis of the membership function,the salt tolerance of 72 maize inbred lines was evaluated,and 10 salt-tolerant materials were screened,114/A,Qin Qingnong/05m,H816,KH207,Spring 2-1,Liao 3162,77,L172,F140,North 6,KH831,L277self.The germination rate,germination potential,relative germination rate and relative germination potential,the greater the salt stress concentration,the greater the decrease,the lower the salt-resistant material than the salt-sensitive material.2.The results of pot experiment showed that Salt stress could inhibit the growth of maize inbred lines,and also lead to the changes of physiological and biochemical indexes.The results showed that there were 10 kinds of salt-resistant materials F140,Spring 2-1,A27-1,1583,KH207,H482,114/A,Qinqingnong/05m,A27-2-1,A27-4-2,B13.the seedling height,stem diameter,leaf area,chlorophyll content and biomass of maize seedlings decreased with the increase of stress degree,and the effect on the underground was higher than that in the upper part Root-to-root ratio increases.The physiological and biochemical indexes of maize inbred lines also changed significantly to reduce the damage of salt and increase the cell membrane permeability.The contents of proline and malondialdehyde were significantly increased,the activity of antioxidant enzymes increased significantly.3.Field test results show:Salt stress had significant effects on the morphology,photosynthesis and yield of maize inbred lines at different growth stages,according to the comprehensive evaluation of salt tolerance in field experiment,4 high salt tolerance maize inbred materials were obtained:KH207,KH831,A27-2-1,F140.under salt stress,the plant height,stem diameter of maize inbred lines were decreased at different growth stages,the net photosynthetic rate decreased,the chlorophyll content decreased and the organic matter production capacity decreased.With the increase of salt stress,the net photosynthetic rate of maize inbred lines decreased,intercellular carbon dioxide concentration increased,transpiration rate increased.The yield of maize inbred lines decreased,and the salt stress concentration was negatively correlated with the yield.The salt yield was higher than that of the sensitive salt.Maize emergence to jointing stage is not sensitive to salt stress,salt tolerance is good.The big trumpet period of the maize growth period of maize is the most salt tolerant,and the flowering period is the most sensitive and least salt-resistant period of maize.The sensitivity of Maize to salt stress during grain filling stage,and the salt tolerance of maize were lower than that of big mouth,and higher than that of flowering stage.4.Principal component analysis was used to identify the system of salt tolerance:0.3%NaCl solution was the suitable concentration of salt tolerance in germination period,and salt tolerance index,relative germination rate,relative salt damage rate and germination rate were the suitable indexes.0.45%NaCl solution was suitable concentration for salt tolerance at seedling stage,stem diameter,leaf area,SPAD,SOD,POD,water content is suitable index.Plant height,stem diameter,SPAD and seedling emergence rate were the suitable indexes of maize inbred lines for salt tolerance at seedling stage.Plant height,membrane permeability were suitable indexes for maize inbred joint salinity identification.Plant height,SPAD,Pn,Gs,Ci,Tr were the suitable indexes for maize inbred Large bell stage.The plant height,stem diameter,Pn,were suitable for the identification of maize inbred Flowering stage.Plant height,stem diameter,SPAD,Pn,were the suitable indexes for maize inbred during grain filling stage.The leaf greening,grain number,single ear yield and yield were suitable for the identification of maize inbred lines at maturity.Soil total salt content of 5.76g/kg,can be used as maize inbred line salt tolerance identification of the appropriate concentration.5.The results showed that the maize inbred lines KH207,F140,H482,6,and 1583 had stronger salt tolerance,and could be used for the selection of new varieties of salt tolerant maize and the cultivation of saline alkali soil in the following experiments.6.In this study,KH207,L488,L277 and 7922 were suitable for cultivation under the condition of salt content of 3.91 g/kg.the materials L172,H482,B13,F140,2-1 were suitable for cultivation under the condition of salt content of 5.76g/kg,the materials A27-2-1,H816,8-2-2 114/A/05m,Qin Qing farm 1583,were suitable for cultivation under the condition of salt content of 7.97 g/kg.