Effect of ethylene and temperature on physiological and biochemical changes during fruit drop of longkong postharvest

摘要

Longkong (Aglaia dookoo Griff.) is a popular tropical fruit that currently experiences around 99.37% domestic consumer demand. The main problem in terms of export is that longkong fruit drops from its bunch after harvesting. Therefore the objective ofthis research is to study the development of fruit drop in longkong bunches being harvested and stored at room temperature. Weight loss, fruit drop and polygalacturonase (PG) activity increased rapidly during storage time; while firmness, respiration rate and ethylene of longkong fruit bunches decreased after storage at room temperature. Activity of the enzymes pectinesterase (PE), cellulase (Cx) and peroxidase (POD) of longkong fruit slightly increased up to six days and then decreased until the end of storage. The effect of ethylene (at the concentration of 0, 200 and 400 ppm) on physiological and biochemical changes during fruit drop of longkong postharvest was evaluated. Dipping longkong in 200 and 400 ppm ethephon rapidly increased fruit abscission and respiration rate. The untreated fruit showed increased ethylene production and activity of enzymes PG, PE and Cx, and weight loss was delayed longer than longkong dipped in 200 and 400 ppm ethephon. Firmness and POD were not significantly different between the fruit treated with ethephon and those untreated. Effects of temperature (at 13 and 25°C) on physiological and biochemical change during fruit drop of harvested longkong bunches was also evaluated. The results indicate that storage at 13°Cdelayed the weight loss, fruit drop, firmness, respiration rate, ethylene production and activity of enzymes pectinesterase (PE), cellulase (Cx) and peroxidase (POD).