赤霉素及二氢茉莉酸丙酯对抑制温州蜜柑果实浮皮的影响OACSTPCD

In order to investigate the methods of preventing citrus fruit from puffing and the mechanism of gibberellin(GA3)and propyldihydrojasmon(PDJ)inhibiting peel puffing,the effects of calcium or GA3 and PDJ on the fruit puffing index and fruit quality were examined by foliar spraying on satsuma mandarin Miyagawa with delayed harvest cultivation,and the alterations in peel cell wall structure,cell wall substance content,hydrolytic enzyme activity,phytohormone content,and the relevant gene expression with GA3 and PDJ-treated were analyzed.The results demonstrated that all treatments were able to reduce the fruit puffiness index.However,only spraying twice with GA3 and PDJ-treat before harvest could control the fruit puffiness index at a low level without affecting the external and internal quality of the fruit.In the GA3-and-PDJ treatment,the activity of pectin methylesterase(PME),cellulase(Cx)and the expression of CitPME and CitCx genes was suppressed.The protopectin and hemicellulose content in the peel and fruit hardness were increased in GA3-and-PDJ treatment.Compared with congtrol,cellulose content decreasing was delayed,and the degree of membrane lipid peroxidation in the peel was reduced.Meanwhile,the expression of the CitACO gene was suppressed,which resulted in a decrease of ethylene synthesis,while the CitETR1 gene was up-regulated,and the IAA content and CitIAA27 gene expression increased.The results of this study indicated that combined spraying of GA3-and-PDJ twice was the most effective method to prevent the peel puffing of satsuma mandarin with delayed harvest cultivation.The treatment inhibited the degradation of cell wall structural substances,reducing the degree of membrane lipid peroxidation,decreasing ethylene synthesis and reducing the sensitivity of peel cells to ethylene,and improving peel IAA content,and thus inhibiting peel senescence and the occurrence of peel puffing.This research provides a theoretical and practical foundation for understanding the mechanism of citrus fruit puffing and developing strategies to control citrus puffing.