Effects Of Storage Nutrition On Growth And Nitrogen Absorption And Utilization Of Apple

Storage nutrition refers to the nutrients stored in the roots,stems and branches during the dormancy period,including carbohydrates,proteins and nitrogenous acids.The level of storage nutrition is important to the safe overwintering of fruit trees and the growth and development of the roots and shoots in the early spring of the fruit tree and the flowering and fruit setting of the fruit trees.In the current apple production,the level of storage nutrition is a major limiting factor of apple quality and yield and nitrogen utilization.How to improve the level of storage nutrition and promote the absorption and utilization of nutrients in fruit trees is an important guarantee for achieving high quality and high yield in orchard.In this study,in order to provide theoretical basis for increasing the technology of nitrogen absorption and utilization of fruit trees in spring,six-year-old�Fuji3'/SH6/Malus hupenensis Rhed.was used as a test material,and ¹⁵N tracer technique was used to study the effects of leaf picking,nitrogen spraying in branches and foliar application of nitrogen in late autumn on the growth of tree and nitrogen absorption and utilization in spring.The main results were as follow:1.Effects of picking off leaves and branches spraying nitrogen on apple growth and nitrogen absorption and utilization in spring,the experiment was studied by not picking the leaves and branches without spraying nitrogen?CK?,picking off leaves and branches not spraying nitrogen?T1?,picking off leaves and branches spraying nitrogen?T2?,not picking the leaves and branches with spraying nitrogen?T3?.The main results were as follow:From April 4th to May 15th,the content of soluble sugar,starch and soluble protein in root system decreased with time goes by,and the content of free amino acids in root system increased gradually.In different treatments,the content of soluble sugar and starch in root of leaf picking off?T1,T2?was significantly lower than that of non leaf picking?CK,T3?,while?T3and CK?,?T1 and T2?had no significant changes in soluble sugar and starch content in root system.During the whole period of tests,the contents of soluble protein and free amino acid in roots showed a rule of T3>CK>T2>T1.The total root length?28353.31cm?,root total surface area?7168.73cm²?,root tip number?81187.87?were all higher than those of other treatments,and the difference was significant.The root activity of T3 treated between different treatments was the highest.In the new shoot growing stage,the chlorophyll content,leaf area and net photosynthetic rate of leaves were significantly higher than those of other treatments under T3 treatment.In the new shoot growing stage,the Ndff value of root is the highest in all treatments,and the new organs of the upper part of the annual branch,leaf and flower are the next,and the Ndff value of the perennial branch and the trunk is the lowest.The Ndff value of all organs was highest in T3 treatment among different treatments.The nitrogen utilization rate under T3 treatment was the highest,which was 12.15%,CK treatment was 7.74%,and the utilization rate of leaf removal was significantly lower than that of CK,and the nitrogen utilization rate of T1 was only 5.05%,while the nitrogen utilization rate of nitrogen treatment?T2?after leaves extraction was improved,which was 6.65%,but still lower than that of non leaf picking?CK,T3?.2.Effects of foliar application of nitrogen on apple growth and nitrogen absorption and utilization of apple in spring.The effects of foliar applications of nitrogen on apple growth and nitrogen absorption and utilization of apple in early spring were studied by setting 4foliar nitrogen treatments with 0N,1N%,3N%and 5N%?CK,N1,N2,N3?before deciduous.The main results were as follow:compared with the control treatment,the chlorophyll,leaf area and net photosynthetic rate of leaves increased with the increase of foliar spraying concentration.The leaves chlorophyll?50.93?,leaf area?16.57 cm²?and net photosynthetic rate?15.52?mol/?m²�s??of leaves treated by N3 were significantly higher than those of other treatments.N3 treatment increased SOD,POD,CAT enzyme activities and MDA content in leaves effectively.From April 4th to May 15th,all treatments showed that the content of soluble sugar,starch and soluble protein in root system decreased gradually,and the content of free amino acids in root system increased gradually.During the whole experiment period,the contents of soluble sugar,starch,soluble protein and free amino acid in root system showed a rule of N3>N2>N1>CK.The root activity of N3 was significantly higher than that of other treatments,and the total biomass of plants increased by 17.03%,11.52%and8.55%than that of CK,N1 and N2 respectively.Compared with the control,the total root length,root surface area and root tip number of root system were improved to varying degrees by N1,N2 and N3 treatment.Among them,the effect of N3 treatment was the most obvious.In the new shoot growing stage,¹⁵N were preferentially distributed to the roots,and then transported to aboveground for the construction of new organs after fertilization in spring,the Ndff value of root is the highest one in all treatments,and the new organs of the upper part of the annual branch,leaf and flower are the next,and the Ndff value of the perennial branch and the trunk is the lowest.The Ndff value of all organs was highest in N3treatment among different treatments.Under N3 treatment,the utilization rate of nitrogen fertilizer of apple in spring was up to 13.61%,while N2 and N1 were 10.29%and 9.11%respectively,and the lowest utilization rate of CK was 7.65%.