Study On The Relationship Between Canopy Characteristics,Photosynthetic Characteristics And Fruit Yield And Quality Of Ziziphus Jujuba Cv. Huizao In Different Shapes

In this study,Ziziphus jujuba cv.Huizao trees in Alar Farm of the First Division of Xinjiang Construction Corps were used as experimental materials to solve the problems of poor quality and low yield of jujube fruit caused by the disorder and inconsistent shape of jujube trees,which made it difficult to achieve scientific and effective unified management.The relationship between canopy characteristics,photosynthetic characteristics and fruit yield and quality was preliminarily explored by comparing the simplified"trunk"shape with the conventional small-crown sparse-layer shape of Ziziphus jujuba cv.Huizao trees.The main results are as follows:1.Relative to the small crown sparse layer tree,the branch size of the main trunk of Ziziphus jujuba cv.Huizao is less,the LAI is smaller,and the MTA,DIFN and TRANS are larger.The number of trunk-shaped secondary branch and fruiting branch were 27/plant and 407/plant respectively,and the number of small crown sparse layer-shaped secondary branch and fruiting branch were 44/plant and 717/plant respectively.The LAI of two tree forms increased month by month from May to July,and declined in August and September after reaching the peak in July?trunk shape 3.62,small crown sparse layer shape 4.13?.The change rule of MTA was similar to that of LAI,but the peak appeared in August?trunk shape 50.8°,small crown sparse layer shape 46.1°?.The change rule of DIFN and MTA was just opposite,decreasing month by month from May to August and reaching the lowest value in August?trunk shape 0.16,small crown sparse layer shape 0.08?.The canopy sparse layer shape increased in September after 0.08,and the values of TRANS in May to September were larger in trunk tree shape.2.The Pn,Gs and Evap of the trunk-shaped tree of Ziziphus jujuba cv.Huizao are larger than that of the small crown sparse layer-shaped tree,and the Ci is smaller than that of the small crown sparse layer-shaped tree.Seasonal variations:The Pn,Gs,Evap and Ci of the two tree types increased month by month from May to August,peak in August?Pn:trunk shape 19.46?mol/?m²·s?,small crown sparse layer shape17.05?mol/?m²·s?;Gs:trunk shape 0.647 mmol/?m²·s?,small crown sparse layer shape 0.438 mmol/?m²·s?;Evap:trunk shape 6.10 mmolH₂O/?m²·s?,small crown sparse layer shape 4.84 mmolH₂O/?m²·s?;Ci:trunk449.91?molCO₂/mol,small crown 386.35?molCO₂/mol?,decline in September.In diurnal variations:At the beginning of August,the diurnal variation of net photosynthetic rate of the two tree forms showed asymmetric"double peak"curve,The first peaks all appeared around 13:00,it is the strongest photosynthesis in the whole day?trunk 18.65?mol/?m²·s?and small crown sparse layer 16.51?mol/?m²·s??,the second peak appears around 17:00;The trough is about 15:00.The net photosynthetic rate of the two tree forms was lower in the morning and in the evening,higher near noon.From 9:00 to 21:00,except for about 15:00,the net photosynthetic rate of the trunk-shaped tree was higher than that of the small-crowned sparse-layered tree.In different crown spaces:At the beginning of August,the Pn,Gs and Evap of the trunk tree shape in different crown layers,positions and directions were significantly larger than that of the small crown sparse layer tree shape,the order of size is:upper layer>middle layer>lower layer,outer layer>Inner hall,southeast side>Northwest side.on the contrary,Ci changes regularly,that is to say,the lower layer>the middle layer>the upper layer,the inner Hall>the outer layer,the northwest side>the southeast side of the crown.By fitting the light response curve,we can see that,at the beginning of August,the light compensation point?LCP?of the trunk-shaped tree of Chinese jujube was lower than that of the canopy-shaped tree,the light saturation point?LSP?and maximum net photosynthetic rate?Pmax?were larger,the LCP value of trunk type was 27?mol/?m²·s?,the sparse canopy shape was 36?mol/?m²·s?,the LSP value of trunk type was 1311?mol/?m²·s?,the sparse canopy shape was 1239?mol/?m²·s?,the Pmax value of trunk type was 24.24?mol/?m²·s?,and the sparse canopy shape was 21.79?mol/?m²·s?.3.The maximum specific leaf weight and chlorophyll content of main trunk and small canopy sparse layers of Ziziphus jujuba cv.Huizao appear in the upper periphery of the canopy,and the specific leaf weight and chlorophyll content of trunk shape were higher,specific leaf weight of trunk shape was 0.12g/cm²,chlorophyll content was 1.81 mg/g,specific leaf weight of small canopy sparse layer shape was0.115 g/cm² and chlorophyll content was 1.71 mg/g,respectively.The minimum specific leaf weight and chlorophyll content of the two types of trees appeared in the lower inner hall of the canopy.There were also significant differences in specific leaf weight and chlorophyll content among different canopy directions,namely,the specific leaf weight and chlorophyll content in the southeast side of the two tree crowns were significantly higher than those in the Northwest side,the specific leaf weight and chlorophyll content of trunk-shaped trees were higher in all directions of crown.4.The yield of the trunk-shaped tree of Ziziphus jujuba cv.Huizao is slightly lower than that of the small-crown sparse-layered tree?The yield per plant of trunk type was 4.82 Kg,and that of small crown sparse layered type was 5.63 Kg?,however,the yield distribution of trunk-shaped trees among canopy layers was more uniform,the small crown sparse layered tree is concentrated in the middle of the canopy.Specifically manifested in:The yield of upper,middle and lower layers of trunk canopy accounted for33.32%,37.01%and 29.61%of the total yield,respectively,the canopy sparse layers were 24.99%,41.65%and 33.36%.Between different parts of tree crown,the yields of the two tree types were mainly distributed around the crown,and the yields of the southeast side were slightly higher than those of the Northwest side.5.Fruit quality of main trunk tree-shaped Ziziphus jujuba cv.Huizao was better than that of small crown sparse layer-shaped.The contents of single fruit weight,soluble solids,soluble sugar and vitamin C of jujube fruits in trunk-shaped tree were higher than those in small-crown sparse-layered tree at different levels,positions and directions of crown.For example,the single fruit weight 11.4g,soluble solids 34.3%,soluble sugar 32.03%and vitamin C 431.75 mg/100g of jujube fruits in the upper periphery of trunk canopy,the single fruit weight was 10.21g,soluble solids 31.9%,soluble sugar 30.36%and vitamin C 424.79mg/100g of the canopy sparse layer.Conclusion:Under the plant and row spacing of 1 x 3 m,trunk shape is more suitable for local Ziziphus jujuba cv.Huizao production than small crown sparse layer shape.