College of Horticulture, South China Agricultural University, Guangzhou, China.
Sci Rep. 2021 Feb 17;11(1):3976. doi: 10.1038/s41598-021-83519-z.
Plant growth and development are tightly regulated by phytohormones. However, little is known about the interaction between auxin and gibberellin acid (GA) during flower stalk elongation and how it is directly related to organ formation. Therefore, the effects of indole acetic acid (IAA) and GA treatments and their interaction on flower stalk elongation in flowering Chinese cabbage were investigated. The growth of flowering Chinese cabbage is regulated by IAA and GA and the opposite results were observed after treatments with uniconazole (GA synthesis inhibitor) and N-1-naphthylphthalamic acid (NPA) (auxin transport inhibitor). Anatomical analysis of the pith region in stalks revealed that IAA promoted expansion via signal transduction and transport pathways. GA regulated the elongation of flower stalks by controlling GA synthesis and partially controlling the IAA signaling pathway. GA also had a stronger effect on stalk elongation than IAA. The results of qRT-PCR and histological analysis revealed that GA and IAA induced the expansion of cell walls by activating the expression of genes encoding cell wall structural proteins such as Expansin (EXP). These findings provide new insights into the mechanism of stalk formation regulated by the combination of IAA and GA.
植物的生长和发育受到植物激素的严格调控。然而，人们对生长素和赤霉素（GA）在花茎伸长过程中的相互作用以及它如何与器官形成直接相关知之甚少。因此，研究了吲哚乙酸（IAA）和 GA 处理及其相互作用对开花白菜花茎伸长的影响。开花白菜的生长受 IAA 和 GA 调控，经 uniconazole（GA 合成抑制剂）和 N-1-萘基邻苯二甲酰亚胺（NPA）（生长素运输抑制剂）处理后观察到相反的结果。对茎节髓区的解剖分析表明，IAA 通过信号转导和运输途径促进扩张。GA 通过控制 GA 合成和部分控制 IAA 信号通路来调节花茎的伸长。GA 对茎伸长的影响也强于 IAA。qRT-PCR 和组织学分析的结果表明，GA 和 IAA 通过激活细胞壁结构蛋白（如 Expansin（EXP））基因的表达来诱导细胞壁的扩张。这些发现为 IAA 和 GA 共同调节茎形成的机制提供了新的见解。
