Postharvest Changes in Activities of GS, ACC Synthase, ACC Oxidase, and PAL in Bamboo Shoots at Different Storage Temperatures

Abstract

In this study, we investigated the postharvest changes in glutamine synthetase (GS; EC 6. 3. 1. 2), 1-aminocyclopropane-1-carboxylate (ACC) synthase (EC 4. 4. 1. 14), ACC oxidase (EC 1. 4. 3) and phenylalanine ammonia lyase (PAL; EC 4. 3. 1. 5) activities in relation to ammonia content, ethylene production, respiration rate, and texture and color changes after harvest of moso bamboo (Phyllostachys edulis) shoots stored at 1 and 20°C for up to 9 days. GS activity decreased in shoots stored at 20°C with increasing ammonia content up to approximately 6-fold the initial content after a 9-day storage period. Although the highest ACC oxidase activity corresponded to the highest ethylene production, the highest ACC synthase activity was delayed 8 h or more compared with that in the previous study. The development of PAL activity coincided with an increase in breaking strain at 20°C up to 3 days. Low-temperature storage of shoots at 1°C retained good shoot color and quality since it was effective in decreasing respiration rate, ammonia accumulation, ACC synthase, ACC oxidase, and PAL activities after the harvest of moso bamboo shoots.