毛竹茎竿纤维细胞发育过程中酸性磷酸酶的动态变化

应用磷酸铅沉淀技术对毛竹(Phyllostachys edulis(Carr.)H.De Lehaie)茎竿纤维细胞发育过程中酸性磷酸酶的动态变化进行了研究。结果表明:在纤维原始细胞形成期,酸性磷酸酶主要分布于质膜和细胞核染色质上;在初生壁形成早期,酸性磷酸酶主要分布在质膜、液泡和细胞核染色质上,并在质膜上密集分布;随着初生壁的继续形成,质膜上的酸性磷酸酶逐渐减少呈稀疏分布,而细胞核染色质上的酸性磷酸酶逐渐增多呈密集成团分布;随着次生壁的形成,染色质开始凝聚,细胞核染色质上分布的APase活性有所减弱。但随着液泡膜的裂解,在裂解的液泡膜、降解的线粒体和细胞质上具有APase活性。随着次生壁持续增厚,APase在胞间连丝、质膜、质膜内陷结构、运输小泡和凝聚并边缘化的染色质等部位持续多年保持较强的活性。因此,酸性磷酸酶可能是引起纤维细胞程序性死亡的原因之一,不同的酸性磷酸酶同功酶可能分别参与了毛竹茎秆纤维细胞初生壁和次生壁的形成,以及细胞程序性死亡过程中原生质体的降解。酸性磷酸酶持续保持较高活性与竹子纤维细胞的长寿特性也密切相关。

The Dynamic Changes of Acid Phosphatase during the Fiber Development in Phyllostachys edulis Culm

The distribution of acid phosphatase during fiber development in the culm of Phyllostachys edulis(Carr.) H.De Lehaie was studied by using the lead precipitation method.Acid phosphatase(APase) was mainly localized on the plasmalemma and nuclear chromatin at the stage of fiber initial formation.With the primary wall formation,the enzymatic activity in the cells was examined on the plasmalemma,tonoplast and nuclear chromatin.The enzyme activity on the nuclear chromatin would condensely be accumulated at the later stage of fiber primary wall formation.As fiber secondary wall formed,APase was deposited on the plasmalemma,the disintegrated cytoplasm,mitochondrion and tonoplast and the agglutinated chromatin.With the continual thickening of the secondary wall,APase activity on the plasmalemma,plasmodesmata,plasmalemma invagination and transfer vesicles and agglutinated chromatin of fiber were persistent for many years.These findings indicated that the APase condensely accumulated on the nuclear chromatin was closely related to the occurrence of fiber programmed cell death(PCD),and APase had functions in the whole formation of primary and secondary wall,and the disintegration of protoplast during PCD,and the persistent APase was correlated to the long-lived characteristic of fiber.