Effects Of Girdling And Growth Regulators On Branch Development And Accumulation Of Carbon And Nitrogen Metabolites In ’Xinwen 81’ Walnut

This experiment used’Xinwen 81’walnut as the research material and conducted girdling and foliar spraying of growth regulators on the walnut from June to October 2022.The effects of girdling and foliar spraying on the growth,photosynthesis,enzyme activity,and fruit quality of the main fruiting walnut were studied,and the differences between each treatment were analyzed to explore the best way to use girdling and growth regulators.The tree shape construction provided a scientific basis for the application of girdling and growth regulators Provide theoretical basis for improving quality and increasing production.The main results of this experimental study are as follows:（1）The treatment of girdling and foliar spraying with growth regulators had a certain impact on the nutrient branch diameter and internode length of walnut,and both treatments could increase the fruit branch diameter and shorten the internode length to varying degrees;The internode length of nutrient branches after girdling treatment was significantly lower than that of the control（decreased by 26.6%）,but the number of internodes significantly increased（30.4%）;After two rounds of girdling treatment,the internode thickness of nutrient branches increased by 16.5%compared to the control;When the concentration of betamethasone sprayed on the leaves was 300mg/L,the total length of nutrient branches in the treatment significantly decreased by 47.29%compared to the control,but the thickness of nutrient branches significantly increased by 22%,the length of internodes decreased by 20.16%,but the number of internodes significantly increased（47.91%）;When the concentration of betamethasone was 400mg/L,the number of nutrient branches in the treatment significantly increased by 50%compared to the control,and the internode diameter significantly increased by 63.5%;The total number of flower buds significantly increased after girdling and foliar spraying of betamethasone and uniconazole compared to the control.This indicates that girdling and foliar spraying of growth regulators can significantly affect branch thickness and internode growth characteristics.（2）Both girdling and growth regulator treatments showed varying degrees of improvement in chlorophyll content and photosynthetic characteristics of walnut.Moderate spraying of chloramphenicol and uniconazole significantly increased chlorophyll content in walnut nutrient branches and leaves,with400mg/L chloramphenicol and 250mg/L uniconazole treatments having the best effect on improving leaf chlorophyll.The net photosynthetic rate（Pn）,intercellular CO₂ concentration（Ci）,stomatal conductance（Gs）,and transpiration rate（Tr）of walnuts all reached their peak during the oil conversion period in this experiment.During this period,the net photosynthetic rate of leaves treated with two cycles of girdling was significantly increased compared to the control.When measuring the photosynthetic indicators,the net photosynthetic rate of walnuts showed regular changes,while the intercellular CO₂ concentration The changes in stomatal conductance and transpiration rate are irregular.（3）Under different girdling and growth regulators,the activities of peroxidase,catalase,superoxide dismutase,sucrose synthase and neutral invertase in walnut leaves increased significantly.High enzyme activity enhances the activity of nutrient branches,which helps to accumulate sucrose in the branches.However,the effect of high concentration of uniconazole treatment on enzyme activity improvement is better than that of sulfamethoxazole treatment.During the oil conversion period,the sucrose synthase treated with 300mg/L uniconazole increased by 304.31%compared to the control;The treatment with500mg/L concentration of betamethasone significantly reduced the activity of neutral invertase,which may be due to the early senescence of leaves caused by high concentration of betamethasone treatment.（4）The treatment with a concentration of 500mg/L of betamethasone significantly reduced the carbon content of the leaves,while the treatment with a concentration of 200mg/L of uniconazole significantly increased the carbon content of the leaves.At different stages of the fruit,the treatment with uniconazole showed varying degrees of improvement in the carbon content of walnut leaves,while the treatment with betamethasone had the opposite effect,showing a reducing effect.The treatment with a concentration of300mg/L of uniconazole significantly increased the carbon nitrogen ratio of walnut leaves.（5）The interval girdling treatment significantly increased the transverse,longitudinal,and lateral diameters of walnut fruits,significantly reduced the thickness of the fruit’s kernel shell by 28.94%,and significantly increased the single fruit weight and kernel yield by 26.83%and 14.75%,respectively.Amine treatment significantly increased the lateral diameter of walnut fruit,decreased the fruit shape index,and made the fruit more round.The 250mg/L uniconazole treatment significantly increased the lateral and longitudinal diameter of walnut fruit,and reduced the thickness of the fruit’s core shell.The treatment with500mg/L metamine significantly increased the single fruit weight of the fruit by 15.67%,while the treatment with 250mg/L uniconazole significantly increased the kernel weight of walnut fruit by 14.19%.The soluble protein content of walnuts significantly increased by 31.70%after treatment with 300mg/L melamine,but significantly decreased the soluble sugar content of the fruit,reaching 34.11%;The crude fat content of walnuts significantly increased by 10.76%after being treated with 500mg/L meta amine;The higher the concentration of Uniconazole treatment,the lower the soluble sugar content in walnut fruit.The300mg/L Uniconazole treatment significantly reduced the soluble sugar content by 19.46%compared to the control.（6）The treatment of two circles of interval girdling significantly increased the lignin and cellulose of middle and rear branches,but significantly reduced the hemicellulose.Amine treatment reduced the lignin content in various parts of walnut branches,and in the third part of the branches,400mg/L Amine treatment significantly reduced the lignin content,reaching 64.05%.Uniconazole treatment can significantly increase the content of lignin,cellulose and hemicellulose in the second to fourth parts.