Comparative Differences In Carbon And Nitrogen Metabolism Of Young And Old Leaves From Wild And Cultivated Soybean Under Low Nitrogen-stress Conditions

Nitrogen is one of the essential mineral nutrients in the process of plant growth,and it is also a key factor limiting crop yield and quality.When nitrogen deficiency,plant growth will be inhibited,which will lead to crop yield and quality decline.Increasing the amount of nitrogen fertilizer can promote the growth and development of plant,increase the yield and quality of soybean.Excessive application of nitrogen fertilizer leads to low nitrogen use efficiency and high nitrogen loss.These losses caused serious environmental pollution through soil runoff,leaching,denitrification,volatilization and other ways,which affected the sustainability of agricultural production.Therefore,cultivating low nitrogen tolerant varieties,improving nitrogen use efficiency and reducing nitrogen use are effective strategies for sustainable agriculture.Carbon and nitrogen metabolism in young and old leaves of wild soybean and cultivated soybean were measured under low nitrogen stress.Wild soybean is the ancestor of cultivated soybean,which has a lot of rich genetic diversity.In order to adapt to the long-term evolution process,it has evolved many excellent germplasm characteristics,such as rich protein content,strong stress resistance,insect resistance,disease resistance,salt resistance and many other excellent traits.It is a valuable plant genetic resource in China and even the whole world.In order to explore the regulation mechanism of wild soybeans to adapt to low nitrogen stress,this study used wild soybeans and cultivated soybeans as experimental materials,and artificially simulated low nitrogen stresses to treat the two seedlings.Growth indexes,ion accumulation,photosynthetic parameters and activities of key enzymes in nitrogen metabolism of wild soybean and cultivated soybean under low nitrogen stress were studied.The main purpose of this experiment is to study the physiological adaptation mechanism and difference between wild soybean and cultivated soybean under low nitrogen stress,provide reliable theoretical basis for improving cultivated soybean using wild soybean and cultivating low-nitrogen tolerant crop varieties,and reveal the dynamic response process of carbon and nitrogen coupling relationship.The results showed that the growth of wild soybean was better than that of cultivated soybean under low nitrogen stress.Under different intensities of low nitrogen stress,especially under high intensity stress,the root length and root shoot ratio of wild soybean increased significantly.The young and old leaves of wild soybean maintained stable balance of photosynthetic gas exchange parameters,photosynthetic pigment content,anion and cation content.Therefore,compared with cultivated soybean,wild soybean could maintain stable balance of carbon and nitrogen metabolism under low nitrogen stress,which is the mechanism of resistance of wild soybean to low nitrogen stress.This study provided a clear idea and reliable theoretical basis for improving and cultivating soybean by using wild soybean and studying the low nitrogen tolerance of other plants.It is of great significance to promote the green and sustainable development of agricultural production.