GA3处理对采后竹笋木质化及内源激素水平的影响

 研究了外源GA₃ 浸泡处理对采后竹笋木质化的生理生化变化及内源激素水平的影响。结果表明: 竹笋贮藏期间, 苯丙氨酸解氨酶(PAL) 、肉桂酸- 4 - 羟化酶(C4H) 和过氧化物酶( POD) 活性先增加后减少, 木质素含量和组织硬度逐渐增加, 而可食用率逐渐下降, GA₃ 和IAA含量逐渐减少, ABA含量先增加后减少。PAL、C₄H和POD活性与ABA /GA₃ 的比值呈正相关。外源GA₃ 处理能增加内源GA₃ 含量, 降低ABA /GA₃ 的比值, 并抑制PAL、C4H和POD活性的上升, 降低木质素含量和硬度, 提高可食用率, 从而延缓竹笋木质化进程。推测外源GA₃ 处理可能通过降低ABA /GA₃ 的比值来延缓竹笋木质化进程。

Effects of GA3 Treatment on Lignification and Endogenous Hormone Levels of Postharvest Bamboo Shoots

The effect of treatmentwith 50 mg·kg^{- 1} GA₃ solution for 30 min on lignification and endogenous hormone levels in postharvest bamboo (Phyllostachys praecox f. preveynalis) shoots were investigated. Results showed that the activities of phenylalanine ammonia lyase ( PAL) , cinnamate 4-hydroxylase (C₄H) and peroxidase ( POD) increased initially and declined later during the 30 days storage at 2 ℃. The lignin content and firmness continuously increased, but edible rate decreased gradually. The contents of GA₃ and IAA declined continuously, where as ABA content increased firstly and then declined. The activities of PAL, C₄H and POD were correlated with the rate of ABA /GA₃. Exogenous GA₃ treatment increased endogenous level of GA₃ content and decreased the rate ofABA /GA₃ aswell as inhibited the increase of PAL, C₄H and POD activities in bamboo shoots. The firmness and lignin content in GA₃ treated bamboo shoot were lower than those of control, while the edible rate was higher than that of control. It is suggested that GA₃ treatment retarded lignification through decreasing the rate of ABA /GA₃ in postharvest bamboo shoots.