The relationship between lignification and endogenous hormone content of excised bamboo shoots

chinois. 研究采后竹笋贮藏期间的木质化机理，探讨采后竹笋内源激素对木质化进程的调控作用。以采收后雷竹笋和毛竹笋为材料，分析了两个品种竹笋在（2±1）and#61616;C下贮藏期间内源激素（IAA、GA3、ABA）含量和木质素合成相关酶活性的动态变化规律。雷竹笋和毛竹笋贮藏期间，GA3和IAA含量都逐渐减少，而ABA含量先增加后减少，其中雷竹笋的GA3、IAA和ABA含量高于毛竹笋的。两个品种竹笋的苯丙氨酸解氨酶(PAL)、4-香豆酸辅酶A连接酶(4CL)和过氧化物酶（POD）活性都先增加后减少，木质素和纤维素含量逐渐增加，导致竹笋组织硬度增加。经相关分析发现，两个品种竹笋的PAL、4CL和POD活性与ABA/GA3的比值都呈显著正相关。ABA/GA3比值的变化对竹笋木质化起着关键的调控作用，推测通过降低ABA/GA3比值可抑制PAL、4CL和POD活性而延缓竹笋的木质化进程。

anglais. In order to study the mechanism of lignification and research on the impacts of endogenous hormone (IAA, GA3, ABA) on lignification in excised bamboo shoots. The relationship between endogenous hormone (IAA, GA3, ABA) levels and enzyme activities related to lignification of Phyllostachys praecox f. preveynalis and Phyllostachys pubescens Mazel were investigated. The content of GA3 and IAA in the two bamboo shoots declined continuously, but ABA content increased initially and declined later. The content of endogenous hormone (IAA, GA3, ABA) in excised bamboo shoots of Phyllostachys praecox f. preveynalis were higher than those of Phyllostachys pubescens Mazel. The activities of phenylalanine ammonia lyase (PAL), 4-coumarate CoA ligase (4CL) and peroxidase (POD) increased initially and declined later during the storage. The content of lignin and cellulose and firmness of bamboo shoots continuously increased. The activities of PAL, 4CL and POD were significantly correlated with the ratio of ABA/GA3. These results indicated that the ratio of ABA/GA3 is very important for lignification in excised bamboo shoots. The lignification of excised bamboo shoots maybe retarded when the activities of PAL, 4CL and POD were inhibited by decreasing ABA/GA3 ratio.