Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045 USA.
Am J Bot. 2000 Oct;87(10):1540-5.
The induction of shoot buds in the moss Funaria hygrometrica is a classic and quantitative bioassay for cytokinin. This cytokinin-stimulated response can be inhibited by the plant hormone abscisic acid, ABA; the inhibition is concentration dependent and was proposed for use as a bioassay for ABA. This paper characterizes the ABA inhibition of the cytokinin-stimulated formation of shoot buds. Experiments transferring protonema between cytokinin and cytokinin plus ABA show that ABA does not interfere with the initial perception of cytokinin. Other experiments compare the results of transferring protonema from cytokinin to cytokinin-free medium or to medium with cytokinin plus ABA and reveal that ABA acts by blocking the cytokinin-mediated stable commitment of nascent buds. Extension of the technique of double-reciprocal plots to this whole-organism bioassay finds that ABA is not a competitive inhibitor of cytokinin. Analysis of the ABA inhibition of bud formation identifies a new regulatory step in the developmental process of bud formation in mosses.
在藓类植物水苔中芽的诱导是细胞分裂素的经典和定量生物测定法。这种细胞分裂素刺激的反应可以被植物激素脱落酸（ABA）抑制；抑制作用呈浓度依赖性，并被提议用作 ABA 的生物测定法。本文描述了 ABA 对细胞分裂素刺激芽形成的抑制作用。在将原丝体在细胞分裂素和细胞分裂素加 ABA 之间转移的实验中表明，ABA 不干扰细胞分裂素的初始感知。其他实验将原丝体从细胞分裂素转移到无细胞分裂素培养基或含有细胞分裂素加 ABA 的培养基中的结果进行比较，揭示 ABA 通过阻断细胞分裂素介导的芽的稳定承诺来起作用。将双倒数图的技术扩展到这个整体生物测定法中发现，ABA 不是细胞分裂素的竞争性抑制剂。对芽形成的 ABA 抑制作用的分析确定了苔藓类植物芽形成发育过程中的一个新的调节步骤。
