Effects Of Source And Sink Regulation On Photosynthesis And Fruit Quality Of Ziziphus Jujuba Mill.cv.’Lingwuchangzao’

Ziziphus jujuba Mill.cv.’Lingwuchangzao’ is a fresh jujube variety with local characteristics,with strong adaptability,high fruit nutritional value,and significant economic and ecological value.In order to explore the suitable leaf-fruit ratio of ’Lingwuchangzao’ and integrate cultivation techniques to improve fruit quality,this experiment uses 9-year-old ’Lingwuchangzao’ grafted plants as the research material.Four treatments are set up by picking leaves and removing fruits.Number of leaves:fruit,The numbers were 10:1,15:1,20:1,25:1,and the leaf-to-fruit ratio 10:1 was used as a control to analyze and compare leaf photosynthesis,leaf carbohydrate accumulation and maturity under different leaf-to-fruit ratio treatments.The main results of the difference in fruit quality during the period are as follows:1.The net photosynthetic rate,stomatal conductance,and transpiration rate of the leaves of’Lingwuchangzao’ show a bimodal change trend at different development stages,and the intercellular CO2 concentration of the leaves shows a single peak change trend.The leaf-fruit ratio is 15:1,20:1,25:1 compared with the control,the net photosynthetic rate of leaves in the fruit expansion stage was reduced by 14.3%,27.6%,16.2%,and in the white maturity stage were reduced by 18.2%,31.0%,and 38.3%.In the expansion stage,the leaf net photosynthetic rate decreased by 18.2%,31.0%,and 38.3%.The carboxylation efficiency increased by 6.9%,0.8%,26.5%,respectively;with the increase of leaf-fruit ratio,the net photosynthetic rate,stomatal conductance,transpiration rate,intercellular CO2 concentration gradually decreased,and the effective water rate gradually increased.2.The results showed that the contents of sucrose and fructose in leaves,glucose,sorbitol and starch in leaves were significantly increased by different leaf fruit ratio treatments.The content of sucrose in leaves decreased at first and then increased at different fruit development stages,while the content of fructose in leaves increased at first and then decreased Fructose content increased with the increase of the ratio of leaf to fruit.In the fruit expansion stage,the sucrose content in leaves of different ratio of leaf to fruit decreased by 57.4%,54.0%,56.7%and 60.4%,respectively,compared with that in young fruit stage;During the whole fruit development period,the content of glucose in leaves decreased gradually,the content of sorbitol continued to accumulate,and the content of starch had no significant change.The content of chlorophyll increased first,then decreased,and then increased.In the young fruit stage,the ratio of leaf to fruit of 20:1 and 25:1 increased by 2.0%and 9.9%respectively.3.Different leaf-fruit ratio treatments could improve the single fruit weight,vertical and horizontal diameter of‘Lingwuchangzao’,promote the accumulation of soluble sugar,soluble solids and anthocyanin in fruit,and reduce the contents of titratable acid,flavonoids and carotenoids in fruit.Compared with the control,the single fruit weight of leaf-fruit ratio 20:1 and 25:1 increased by 19.3%and 21.6%,respectively.The soluble sugar content of leaf-fruit ratio 15:1,20:1 and 25:1 increased by 34.3%,128.9%and 94.1%,The soluble solids content increased by 2.0%,11.4%and 21.0%,The anthocyanin content increased by 3.6%,6.5%and 3.1%,The titratable acid content decreased by 11.8%,5.8%and 19.1%,The flavonoids content decreased by 1.7%,12.5%and 12.7%,The carotenoid content decreased by 12.0%,20.3%and 20.5%,The principal component analysis of fruit quality of ’Lingwuchangzao’ under the four leaf-fruit ratios showed that the fruit quality was the best when the leaf-fruit ratio was 20:1..4.Leaf net photosynthesis rate is significantly positively correlated with transpiration rate,and extremely significantly positively correlated with stomatal conductance;leaf sucrose,fructose and starch content are significantly positively correlated with fruit soluble sugar,and starch content is significantly positively correlated with fruit weight;Leaf sucrose,fructose,starch have a significant negative correlation with fruit flavonoids and carotenoids.In summary,with the gradual increase of the leaf-fruit ratio,the continuous accumulation of carbohydrates in the leaves increased the fruit weight,soluble sugar,and soluble solid content of the’Lingwuchangzao’ fruit,and reduced the titratable acid content.The increase in the ratio increased the sugar-acid ratio and solid-acid ratio of the fruit,and improved the fruit quality.When the leaf-fruit ratio was 20:1,the fruit quality was the best,followed by 25:1.