| China is the largest apple producer in the world.The unreasonable use of N and K fertilizer not only fail to achieve the purpose of increasing yield and improving quality,but also affects the normal growth and development of trees.Hence,the 5-year old‘Changfu2’/Xinjiang Wild Apple arborescent tree was used as the experimental material in this experiment.Study of 12 different proportion of nitrogen and potash（N0 K200、N0 K400、N0 K600、N200 K200、N200 K400、N200 K600、N400 K200、N400 K400、N400 K600、N600 K200、N600 K400、N600 K600）and no nitrogen potash（CK）on apple’s growth,fruit quality and sorbitol,sucrose and galactose,malic acid and other synthetic metabolism related genes expression,to improve the yield and quality of apple,etc.To provide theoretical and technical basis.The main results are as follows:1.All treatments improved the growth and development of apples in different degrees.Under the treatment of N400 K400 and N400 K600,the leaf area,the weight and thickness of 100 leaves were significantly increased,and the accumulation of carbohydrate in apple leaves was also increased.The net photosynthetic rate,transpiration rate,stomatal conductance and chlorophyll content of apple leaves were increased,which promoted the photosynthesis of apple leaves.The relative water content of the leaves was reduced and the instantaneous water use efficiency was improved.The contents of N,Mg,K,Ca and P in the leaves were increased.2.All treatments improved the quality of apple fruit in different degrees.Under the treatment of N400 K400 and N400 K600,the single fruit weight was 252.39g and 247.36g,and under the treatment of N400 K600,the yield of apple reached the maximum of 56.69kg per plant,the fruit hardness reached the maximum of 10.13 kg·cm-2,the soluble solid content reached the maximum of 13.85%,the sucrose content also reached the maximum.Under the treatment of N400 K400,the pigmentation rate was the highest（90.18%）,and the starch content was increased to 3.93 mg·g-1FW.Compared with CK,the contents of sorbitol,glucose,fructose and galactose were significantly increased,and the content of malic acid was significantly reduced to improve the fruit quality.3.The q RT-PCR analysis of related genes affecting apple fruit quality showed that,except for the gene CWIN1,all treatments can increase the expression of related genes.When the N fertilizer application rate is between 0-400 g,with the increase of the K fertilizer application rate,the expression levels of SDH1 and NINV1 genes gradually increase.When it exceeds 400 g/plant,as the K fertilizer application rate increases Increased,the gene expression of genes A6PR,NINV1,SPS1,GALK showed a downward trend;under N400K400 treatment,its gene expression reached the maximum value compared with CK and other treatments.It is consistent with the experimental conclusion in Result 2.The above results proved that different proportions of N and K fertilizer could improve the growth and development of apples and fruit quality,but different treatments had different effects.N400 K400 ratio fertilization can significantly improve the growth and development of trees,improve fruit quality,improve nutrient utilization efficiency,and improve the economic benefits of fruit growers,which provides a reference for the formulation fertilization of apple orchard in the future. |
