Screening Of High Nutrient Efficiency Of Different Rice Varieties Based On Root Morphology

The yield and quality of rice were influenced by genetic characteristics and environmental conditions.Among many environmental factors,nitrogen application was one of the important measures for nitrogen absorption in rice.Different nitrogen application conditions were important factors affecting rice nutrient uptake.Nitrogen?N?,phosphorus?P?and potassium?K?were indispensable to rice growth.Amounts of nitrogen,phosphorus and potassium absorbed by rice were determined by various forms of nitrogen and nitrogen-supply levels.In recent years,nitrogen fertilizer had played a key role in grain yield,yield increase and stability,and had made an important contribution to the protection of grain security in china.However,the utilization rate of nitrogen fertilizer in China was very low,the nitrogen utilization efficiency was only about35%or so,far lower than the rich-country average.The nitrogen fertilizer was widely used and applied extensively in agriculture,that not only reduced the use efficiency of nitrogen,but also caused bad influence on ecological environment.It was effective methods to breed high nitrate utilization efficiency varieties by genetics breeding.The existing studies had showed the index of nutrient uptake rate and grain yield of rice were used to estimate the efficiency of nutrient.It was difficult to actually reflect nutrient absorption efficiency due to too many affecting factors..So the ideal approach was to look for the morphological and physiological characteristic that was closely related to a nutrient character,together as a nutrient efficiency evaluation index.Root morphology of rice as one of the main factors affecting the nutrient uptake and utilization,in the process of nitrogen and phosphorus uptake of potassium nutrient in rice,root parameters change played an important role,with clear N?P?K accumulation correlation screening nutrient efficient genotypes of rice varieties was the effective way to improve the nitrogen utilization efficiency and reduce the environmental pollution.This article unified the domestic and foreign research present situation,To study the correlation,principal component analysis between the absorption,accumulation of nitrogen,phosphorus,potassium and the total root length,total root area,root volume,average root diameter,root number,branch number,number of root morphological index by the method of cultivating the international rice nutrition of rice varieties?lines?under the same nitrogen level(40 mg?L^-1)and different nitrogen forms?ammonium and nitrate?.And by the method of membership function evaluation standard,based on the comprehensive nutrient efficiency value,using the hierarchical clustering analysis to distinguish the 102varieties of rice nutrient efficiency types.By studying variation on root morphology index analysis,plant biomass,nitrogen,phosphorus and potassium content in fitting nitrogen,phosphorus and potassium cumulative stepwise regression model between the optimal quantity and root morphology index,provide the theoretical basis for screening nitrogen efficient varieties.The main results are as follows:1?The study showed the 102 rice varieties under the same nitrogen level(40mg?L^-1)and different nitrogen forms?ammonium and nitrate?index in rice seedling traits under the conditions of the analysis found:in the ammonium nitrogen and nitrate nitrogen conditions,each organ and whole plant the root biomass,nitrogen content,nitrogen content of whole plant and leaf nitrogen accumulation in different organs,and the whole plant phosphorus accumulation and organ and whole plant K accumulation have significant difference in coefficient.These traits can show the difference among rice varieties.Through the analysis of the conditions of rice seedling root morphological traits found in cultured in different nitrogen in ammonium nitrogen conditions,the coefficient of variation is:root tip number>total root length>root branch number>total root area>root crossing number>total root volume>average diameter;in nitrate nitrogen conditions,the coefficient of variation is:root tip number>root branch number>total root length>total root area>root crossing number>total root volume>average diameter of the trend.2?The factor analysis showed that the difference in ammonium nitrogen and nitrate nitrogen cultivation under the condition of principal components,the ammonium nitrogen medium,the first principal component mainly reflects the accumulation of rice seedling biomass,nitrogen accumulation,phosphorus content,potassium content,potassium accumulation,distribution of root density index.The second principal component was mainly reflected in the nitrogen content index of rice seedling stage.The third principal component was mainly reflected in phosphorus content in rice seedling stage.The fourth principal component was mainly reflected as rice root diameter index at seedling stage.Under the condition of nitrate nitrogen cultivation,the first,fourth principal component was the same as the principal component under the condition of ammonium nitrogen culture,but the second,third principal components were reflected as phosphorus content and nitrogen content index in rice seedling stage.3?Correlation analysis of rice nutrition index and morphological index showed that in ammonium nitrogen conditions,the rice root morphology in total root length,total root area,root number,branch number and the correlation between plant biomass was the most significant?R²=0.82⁰.96?.Total root volume,root tip number,crossing number,total root length and nitrogen absorption and accumulation were the most significant?R²=-0.25⁰.91?.Total root length,branch number,crossing number,total root area were most significantly correlated with plant P uptake and accumulation?R²=-0.41⁰.88?.Total root length,total root area,crossing number,root tip number were most significantly correlated with K uptake and accumulation of plants?R²=0.55⁰.92?.Under the condition of nitrate nitrogen cultivation,the total root length,number of root tips,crossing number and branch number of rice root morphology were most significantly correlated with plant biomass?R²=0.83⁰.99?.Total root length,total root volume,root tips,crossing number were most significantly correlated with plant nitrogen absorption and accumulation?R²=-0.48⁰.80?.Total root length,root tip number,crossing number,total root volume and plant P uptake and accumulation were the most significant?R²=0.35⁰.91?.Total root length,root tip number,crossing number,total root volume and potassium absorption and accumulation were the most significant?R²=0.43⁰.92?.4?Under different nitrogen nutrition index of rice cultivation and morphological index of multivariate linear regression analysis showed that in the ammonium nitrogen culture conditions,different varieties of rice root morphology indexes in total root length,total root area,number of branches,the number of cross effects on plant biomass;in total root area effects on plant nitrogen content the maximum number of branches,the number of cross;taking on plant nitrogen accumulation effect;in the crossing number effect on plant phosphorus content;in the number of branches,the crossing number of plant phosphorus accumulation effect;to the total root length of plant potassium content;the total root length,number of branches of plants the biggest influence on potassium accumulation.Cultured in the nitrate nitrogen under the condition of different varieties of rice root morphology indexes in total root length,total root area effects on plant biomass;to the total root length of plant nitrogen content;the total root area on plant nitrogen accumulation effect;with the number of branches,crossing number effect on plant phosphorus content;the total root length,number of branches on plant phosphorus accumulation effect;with the number of branches,number of cross effect on plant potassium content;the total root length and average root diameter of plant K accumulation in the greatest impact,they have reached a significant level.5?Determination of stem leaf biomass,root biomass,stem leaf N accumulation in whole plant,P accumulation,whole plant K accumulation,total root length,root number,the number of branches as the rice seedling nutrient efficiency comprehensive evaluation index,different nitrogen conditions of rice seedling nutrient efficiency value and heat map analysis results showed that 102 rice varieties could be divided into nutrient efficient type,nutrient efficiency,low nutrient type 3 categories,respectively,accounted for 11.76%?58.82%?29.41%of the total varieties.In the ammonium nitrogen and nitrate nitrogen supply conditions,determined‘YY 9'?‘LY 766'?‘?Y602'?‘SLY 1813'?‘ZX 2503'?‘YJ 11'?‘DX 4103'?‘FLY 80'?‘GLY 3905'?‘LJ 7'?‘LRD',‘WO32'for two kinds of nitrogen supply under high nutrient varieties.