| This study was conducted at the agriculture of experimental base of Shenyang Agriculture University from 2015 to 2016.Using pot condition and soil column cultivation method respectively the root morphological and physiological characteristics of sorghum under drought stress,effect of nitrogen on physiological response of sorghum in drought and in different soil layers the root of sorghum physiology and yield were systematically studied.Explored in drought process the change regulation of sorghum root and its effect on above ground parts with the different treatment and different droughr resistance culivar,enriched research content of sorghum drought resistant.And the study provided a theoretical basis and technical support for the drought resistance cultivation measures and breeding direction of sorghum.The main results were as follows:The impact of differences in root morphology and root activity of 2 different drought resistant cultivars of sorghum under drought stress,drought makes Jiza305 in roots at seedling stage and filling stage length,root surface area,root volume was significantly higher than that of Jiza127,showed good root ability rewater Jiza305 can quickly show some compensation effect;drought reduced the root activity of 2 sorghum cultivars,Jiza127 big decline after water recovery slower.Drought stress affected the photosynthesis of 2 sorghum cultivars,stomatal limitation of sorghum cultivars of Pn,Gs,Ci and Tr appeared to varying degrees of decline,and the decline was lower in Ji za305;reduce the drought also caused the PSII reaction center activity,leading to increased Fo and Fv/Fm,qL and ETR were decreased after re watering,Jiza305 good recovery degree miscellaneous,showing a drought adaptability.Drought stress decreased 2 sorghum cultivars in all parts of the organ dry matter accumulation,Jiza127 seriously affected,root dry weight decreased significantly,the root shoot ratio below Jiza305,after rewatering,promote the growth of the ground,2 cultivars of sorghum root shoot ratio decreased drought.The impact of the 2 cultivars of sorghum grain yield and biological yield,harvest index decreased to Jiza127,yield index decline was higher than that of Jiza 305,drought affected greatly,drought resistance index was low.Under different nitrogen levels,the drought of 2 sorghum cultivars of antioxidase system have a different effect due to drought antioxidant enzymes have different degree of elevated nitrogen levels of SOD,POD and CAT activity was significantly higher than no nitrogen level,the activity of antioxidant of B35 enzymes in drought resistant cultivars was higher than Sanchisan;the antioxidant enzyme activity was recovered after rewatering,and the nitrogen significantly decreased the MDA content in leaves and roots at the same time.The drought has reduced 2 sorghum cultivars in different levels of nitrogen on PEP and RUBP carboxylase activity,rewater made 2 kinds of carboxylaseactivity has been restored under normal water condition,nitrogen levels on PEP carboxylase activity was significantly higher than no nitrogen level,while RUBP carboxylase was not sensitive to nitrogen.The stomatal limitation affects sorghum photosynthetic capacity,nitrogen made sorghum cultivars Pn,Gs,Ci and Tr was higher than that of nitrogen level,but also improve the PSII reaction center activity for nitrogen showed obvious promotion of photosynthetic characteristics of drought resistant cultivars B35 light.Nitrogen levels improve sorghum cultivars in different organs of N,K elements of the P element accumulation effect was not obvious.Nitrogen was for sorghum cultivars of dry matter accumulation and yield formation were promoted,which makes the organ dry weight,increased biomass and grain yield.In the process of continuous drought,sorghum root bleeding intensity has continued to reduce,the bleeding intensity of root in different soil layers followed by the size of CK>R60>R30,Jiza305 was high than Jizal27.Drought caused the content of soluble sugar and amino acid in root bleeding of CK than R30 and R60,and soluble protein in the continuous drought in the process of accumulation decreased gradually.ABA concentration of root exudates in different soil drought under different conditions,CK with sustained performance for drought increased firstly and then decreased,while R30 and R60 treated with drought duration decreased in different degree,the content of Jiza305 root exudate.Below the Jilin cross 127 under drought condition,the root of different soil on dry matter accumulation of aerial part was significantly affected,sorghum R30 stem,dry matter accumulation of the city have been remarkably restrained,With the continuous drought decreased.Under drought conditions R30 and R60 roots have been seriously affected,2 sorghum cultivars R30 grain yield and biomass yield was the lowest yield of this variety,R60 for CK fell more obvious,the root yield of sorghum cultivars formed affected to a great extent. |
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