Effects of pre-harvest gibberellic acid spray on endogenous hormones and fruit quality of kumquat ( Citrus japonica ) fruits

Gibberellic acid (GA3) is important in plant growth, development, ripening, and senescence. In the present study, we evaluated the effect of pre-harvest GA3 application on the maintenance of postharvest fruit quality in kumquat (Citrus japonica). On-tree fruits were sprayed with 20 mg/L GA3. Unsprayed harvested fruit stored at 6 °C were used as the control. The contents of indoleacetic acid, GA3, and zeatin ribosides in the GA3-sprayed fruits were significantly higher than those in the control, while the contents of both abscisic acid and titratable acid in sprayed fruits were lower than those in the control. Regarding peel colour, GA3 treatment resulted in a lower decrease in hue angle value, with a slow increase in citrus colour index and browning index. Additionally, GA3 treatment inhibited the accumulation of malondialdehyde. In conclusion, pre-harvest application of GA3 may represent a novel strategy for the preservation of fruits on trees, by maintaining nutritional quality and prolonging the postharvest life of kumquat fruits.