The effects of ethylene on the physiological and biochemical properties of longkong fruits at postharvest stage

In the exportation of longkong (Aglaia dookkoo Griff), a common problem facing the exporters is the premature postharvest shedding of the fruits from the bunch. To cast more light on the issue, this experimental research thus utilized ethephon (i.e. at 0, 200 and 400 ppm concentrations) to investigate the effects of ethylene on the postharvest physiological and biochemical properties of longkong fruits, particularly the fruit drop. In the experiments, the longkong fruits were either untreated (0 ppm) or dipped in 200 or 400 ppm ethephon. The findings revealed that the ethephon treatment significantly increased the fruit abscission and respiration rate. On the other hand, the untreated fruits exhibited a greater amount of ethylene production and the increased polygalacturonase (PG), pectinmethylesterase (PME) and cellulase (Cx) enzyme activities, while the weight loss was noticeably delayed compared to the ethephon-treated fruit group. Nonetheless, the firmness and peroxidase (POD) activity of the untreated and treated fruits were insignificantly different.