Study On The Growth And Development Of Peanut Under Saline-alkali Stress And The Effect Of Modifier Application

【Objective】:Peanut is a medium salt tolerant crop with the highest yield among oil crops in China.Peanut plays an important role in the economy.Saline-alkali stress has become the main bottleneck affecting peanut germination,hindering crop growth and development,reducing crop yield and quality,and restricting the sustainable development of oasis agriculture.This study takes peanut in saline alkali land of Xinjiang as the research object.In view of the response mechanism of different salt tolerant peanut varieties to different saline alkali types and stress concentrations,Yihua 1（YH 1）,Huayu 25（HY 25）,Huayu 39（HY 39）,Fenhua 1（N 1）and Yuhua 37（Y 37）were selected as experimental materials to study the germination of peanut seeds,compare the salt and alkali tolerance of different peanut varieties and analyze the effects of saline-alkali stress on the growth and physiological characteristics of peanut seedlings.To explore the effects of biochar,calcium inhibitor,soil regeneration factor stock solution and microbial agent on the agronomic properties and yield of peanut.This study is expected to provide technical reference for screening and cultivating saline alkali tolerant peanut varieties,improving peanut yield and saline alkali land utilization.【Methods】:There are three types of saline alkali:NaCl,NaHCO₃and NaCl+NaHCO₃（1:1）,four stress concentrations:0.3%,0.6%,0.9%and 1.2%.The 0%was distilled water.All varieties were cultured in light constant temperature incubator for 10 days.The germination index was determined,and the saline alkali tolerant varieties were selected.After the peanut grew to the seedling stage,the taproot length,aboveground fresh and dry weight,underground fresh and dry weight,POD activity,SOD dismutase activity,CAT activity,MDA and Pro content were measured.Field plot experiments were carried out on selected saline alkali tolerant varieties with different application rates of biochar（A）,calcium inhibitor（B）,soil regeneration factor stock solution（C）and microbial agent（D）,the control was no modifier（CK）.After treatment with modifier,the plant height,main root length,first lateral branch length,second lateral branch length,stem and leaf dry matter mass,root dry matter mass,SPAD value,leaf area,full fruit rate,100 fruit weight,100 kernel weight,seed kernel rate and yield of peanut at each growth stage were measured.The results are as follows:【Results】:（1）Different types of saline-alkali stress have different inhibitory effects on peanut seed germination.With the increase of the concentration of saline alkali solution,the germination rate,germination potential and germination index showed a downward trend,and the salt damage rate showed an upward trend.The stress degree of NaCl+NaHCO₃（1:1）was greater than that of NaCl and NaHCO₃.The seeds did not germinate at the concentration of 0.9%and 1.2%.The results of salt damage classification and comprehensive evaluation of membership function showed that Yihua 1 had a high level of salt and alkali tolerance under each salt-alkali stress,and Huayu 39 had the worst salt and alkali tolerance under each salt-alkali stress.（2）With the increase of NaCl,NaHCO₃and NaCl+NaHCO₃stress concentration,the growth of peanut was inhibited,and the main root length of different varieties gradually decreased.The main root length of all varieties decreased sharply under NaCl+NaHCO₃stress.When the stress concentration reached 0.9%,the seeds did not germinate and grow.With the increase of saline-alkali stress concentration,the dry weight and fresh weight of peanut aboveground and below ground also showed a downward trend,and the degree of NaCl+NaHCO₃stress was the greatest.（3）With the increase of saline alkali concentration,the activities of antioxidant enzymes（POD,SOD,CAT）,MDA content and Pro content of peanut seedlings were significantly affected.POD and SOD enzyme activities increased first and then decreased.CAT enzyme activities decreased under NaCl and NaCl+NaHCO₃stress,and increased slightly and then decreased under NaHCO₃stress.The content of MDA and Pro increased significantly.The decrease of POD and SOD activities of saline alkali tolerant varieties Yihua 1 and Huayu 25 was lower than that of other salt sensitive varieties.The MDA content of saline alkali tolerant variety Yihua 1 was the lowest and the Pro content was the highest.The MDA content of saline alkali sensitive variety Huayu 39 was the highest and the Pro content was the lowest.（4）Biochar,calcium inhibitor,soil regeneration factor stock solution and microbial agents all increased the plant height,main root length,first lateral branch length,second lateral branch length,stem and leaf dry weight,root dry weight,SPAD value and leaf area of peanut to varying degrees,and finally significantly improved the full fruit rate,seed kernel rate,100 fruit weight,100 kernel weight and yield.Among them,microbial agent T3 treatment（8750.10 g/hm²）has more significant growth promoting effect on peanut,and the yield increasing effect is the best.Under this treatment,the full fruit rate,seed kernel rate,100 fruit weight and 100 kernel weight of Huayu 25 increased by 19.84%,2.71%,4.05%and 11.94%respectively compared with the control,and Yihua 1 increased by 6.39%,4.98%,34.27%and 7.34%respectively.The yields of Huayu 25 and Yihua 1 were 5981.84 kg/hm²and 6048.40 kg/hm²respectively.【Conclusion】:Yihua 1 is the dominant variety under salt-alkali stress.The concentration of 0.6%of each index can be used as the critical concentration of salt and alkali tolerance of each variety.Under the influence of saline-alkali stress,the growth and development of peanut is hindered.With the increase of salt concentration,the activity of antioxidant enzymes in peanut root tip was inhibited and the Osmoregulation Substances increased significantly.By applying different amounts of biochar,calcium inhibitor,soil regeneration factor stock solution and microbial agent,the growth and development of peanut at each growth stage were significantly promoted,and the dry matter accumulation and yield were significantly increased.Among them,the effect of microbial agent T3（8750.10 g/hm²）was the best.