Faculty of Agriculture, Food, and Natural Resources, University of Sydney, Sydney, Australia.
Plant Signal Behav. 2011 Jun;6(6):901-4. doi: 10.4161/psb.6.6.15323. Epub 2011 Jun 1.
The hormones auxin and cytokinin are key regulators of plant growth and development. As they are active at minute concentrations and regulate dynamic processes, cell and tissue levels of the hormones are finely controlled developmentally, diurnally, and in response to environmental variables. This fine control, along with a regulation of the capacity to respond ensures that the appropriate type, duration and intensity of responses are elicited. We have recently discovered that cytokinin and auxin regulate the synthesis of each other, demonstrating a mechanism for mutual feed back and feed forward control of auxin and cytokinin levels. This regulatory loop could be important for many developmental processes in plants, i.e., in fine-tuning plant hormone levels in the developing meristems of the root and shoot apex. These findings could also give a molecular explanation for earlier observations of auxin and cytokinin effects on cell cultures,1 where specific auxin and cytokinin ratios have been used to trigger different morphological events.
激素生长素和细胞分裂素是植物生长和发育的关键调节剂。由于它们在微小的浓度下起作用，并调节动态过程，因此激素在细胞和组织水平上的发育、昼夜和对环境变量的反应受到精细控制。这种精细控制以及响应能力的调节确保了引发适当类型、持续时间和强度的响应。我们最近发现细胞分裂素和生长素调节彼此的合成，这证明了生长素和细胞分裂素水平的相互反馈和前馈控制的机制。该调控回路对于植物的许多发育过程可能很重要，例如，在微调根和茎尖分生组织中植物激素水平。这些发现也可以为生长素和细胞分裂素对细胞培养物的早期观察结果提供分子解释，其中使用特定的生长素和细胞分裂素比例来触发不同的形态事件。
