四季花金花茶花芽分化进程及叶片内源激素变化

Flower bud differentiation and leaf endogenous hormone changes of Camellia perpetua

关键词:  四季花金花茶, 花芽分化, 持续开花, 内源激素, 濒危植物

Key words:  Camellia perpetua, flower bud differentiation, continuous flowering, endogenous hormones, endangered plant

摘要:

四季花金花茶(Camellia perpetua)为山茶属中唯一几乎全年开花的珍稀濒危植物。为探究其花芽分化进程及不同花发育时期和年生长周期叶片内源激素变化,该研究通过石蜡切片,观察四季花金花茶花芽分化进程,采用酶联免疫吸附法测定不同花发育时期叶片及年生长周期内有花芽和无花芽叶片的脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA₃)和玉米素核苷(ZR)含量的变化规律。结果表明:(1)四季花金花茶花芽分化顺序由外向内进行,分为6个时期,共历时35 d,从花芽分化至开花约2个月。(2)花芽形态分化期叶片ABA、GA₃的含量及GA₃/ABA、(IAA+GA₃)/ZR的比值较高,IAA、ZR的含量及IAA/ABA、ZR/ABA的比值较低。(3)年生长周期内有花芽叶片ABA、IAA、ZR的含量整体上高于无花芽叶片; IAA/ZR及(IAA+GA₃)/ZR的比值整体上低于无花芽叶片。综上表明,四季花金花茶花芽分化至开花时间较短; 高水平的ABA、GA₃及低水平的IAA、ZR有利于花芽分化; 较高水平的ABA、IAA及ZR有利于花芽发育。该研究为该物种持续开花机理的阐明提供了参考依据。

Abstract:

Camellia perpetua is the only rare and endangered plant in the genus Camellia that blooms almost all year round. In order to explore the flower bud differentiation process and the changes of endogenous hormones in leaves at different flower development periods and annual growth cycles, the process of C. perpetua flower bud differentiation was observed by paraffin sections. The contents of abscisic acid(ABA), indole-3-acetic acid(IAA), gibberellin(GA₃)and zeatin nucleoside(ZR)in leaves in different flower development periods and in leaves with flower bud and leaves without flower bud in annual growth cycle were determined by enzyme-linked immunosorbent assay(ELISA). The results were as follows:(1)The flower bud differentiation sequence of C. perpetua was from the outside to the inside, and it was divided into six periods, which lasted 35 d in total, from the bud differentiation to flowering about two months.(2)The contents of ABA and GA₃ and the ratios of GA₃/ABA and(IAA + GA₃)/ZR were higher in flower bud morphological differentiation period, while the contents of IAA and ZR and the ratios of IAA/ABA and ZR/ABA were lower.(3)The contents of ABA, IAA and ZR in the leaves with flower bud were higher than those in the leaves without flower bud. The IAA/ZR and(IAA + GA₃)/ZR ratios were lower than those of the leaves without flower bud. In conclusion, the flower bud differentiation to flowering time of C. perpetua is shorter. High levels of ABA and GA₃ and low levels of IAA and ZR are beneficial to flower bud differentiation; higher levels of ABA, IAA and ZR are beneficial to flower bud development. The study provides the reference for clarifying the continuous flowering mechanism of this species.