| In order to promote fruit fruiting and increase yield,the effects of exogenous gibberellin on fruit structure and endogenous gibberellin were studied.In this experiment,Junzao was used as material,and different concentrations of exogenous gibberellin were sprayed on the leaves of jujube trees at the flowering stage.Photosynthesis of Junzao leaves was determined.The endogenous gibberellin content of fruits at slow growth stage,rapid growth stage,white ripening stage,turning color stage and full ripeness period was detected.Paraffin sections were made to observe the pericarp structure.The indexes related to nutrition quality of Junzao were investigated in the full ripeness period of Junzao.It was expected to determine the effects of different concentrations of gibberellin on fruit quality,leaf photosynthetic efficiency,pericarp structure and endogenous gibberellin content of Junzao at flowering stage.The research results are as follows:（1）The photosynthesis of exogenous gibberellin on Junzao leaves was promoted at low concentration and inhibited at high concentration.At the flowering stage,the photosynthetic effect of the leaves was better after spraying 40 mg/L gibberellin,and the adaptability to the environment was also stronger.（2）After GA3 treatment of 80 mg/L,the transverse diameter,longitudinal diameter,thickness,stem length and chlorophyll of Junzao leaves were the smallest among the six treatments.The cell thickness of epidermis layer of Junzao treated with low concentration at the full ripeness period was slightly greater than that of the control group.（3）The treatment of gibberellin（40 mg/L）could obviously alleviate the wrinkling of the epidermal structure of Junzao.The cell thickness of epidermis layer of Junzao treated with low concentration at the full ripeness period was slightly greater than that of the control group.（4）After 60 mg/L gibberellin treatment,the average single fruit weight of Junzao reached 28.43g,the transverse diameter of Junzao reached 54.03 mm and the cellulose content was at least 425.74 mg/L.Under the treatment of 40 mg/L gibberellin,the fruit quality was the best,the maximum longitudinal diameter of fruit was 36.17 mm,the maximum soluble sugar content was 221.47 mg/g,and the maximum plant yield was5.86 kg.There was no significant difference between fruit shape index and stalk tensile resistance and starch content.（5）After being treated with exogenous gibberellin,the content of endogenous gibberellin in Junzao increased significantly in the young fruit stage and decreased rapidly in the slow fruit growth stage.Gibberellin treatment could significantly increase the content of endogenous gibberellin in fruits.Compared with the control group,the content of endogenous gibberellin in fruits of the red-ripening treatment group was increased by 0.011～0.031 mg/kg.There was a significant negative correlation between endogenous gibberellin content and epidermal thickness of Junzao at the crisp ripe period and full ripeness period.But there was a residual risk compared with the standard of 0.2 mg/kg.The application of gibberellin can significantly improve the fruit quality and leaf photosynthetic efficiency of Junzao.Therefore,it is suggested to spray 40 mg/L gibberellin in Xinjiang for the goal of high yield and good quality. |
