Heilongjiang Academy of Agricultural Sciences Postdoctoral Programme, 368 Xuefu Road, Harbin 150086, China.
Industrial Crops Institute, Heilongjiang Academy of Agricultural Sciences, 368 Xuefu Road, Harbin 150086, China.
Int J Mol Sci. 2019 Feb 12;20(3):792. doi: 10.3390/ijms20030792.
Although phytohormones are known to be important signal molecules involved in wood formation, their roles are still largely unclear. Here, × seedlings were treated with different concentrations of exogenous phytohormones, indole-3-acetic acid (IAA), gibberellin (GA₃), and brassinosteroid (BR), and the effects of phytohormones on growth were investigated. Next, 27 genes with known roles in wood formation were selected for qPCR analysis to determine tissue-specificity and timing of responses to phytohormone treatments. Compared to the control, most IAA, GA₃, and BR concentrations significantly increased seedling height. Meanwhile, IAA induced significant seedling stem diameter and cellulose content increases that peaked at 3 and 30 mg·L, respectively. Significant increase in cellulose content was also observed in seedlings treated with 100 mg·L GA₃. Neither stem diameter nor cellulose content of seedlings were affected by BR treatment significantly, although slight effects were observed. Anatomical measurements demonstrated improved xylem, but not phloem, development in IAA- and BR-treated seedlings. Most gene expression patterns induced by IAA, GA₃, and BR differed among tissues. Many IAA response genes were also regulated by GA₃, while BR-induced transcription was weaker and slower in than for IAA and GA₃. These results reveal the roles played by phytohormones in plant growth and lay the foundation for exploring molecular regulatory mechanisms of wood formation in .
尽管植物激素是已知参与木材形成的重要信号分子，但它们的作用在很大程度上仍不清楚。在这里，我们用不同浓度的外源植物激素（吲哚乙酸（IAA）、赤霉素（GA₃）和油菜素内酯（BR））处理 × 幼苗，研究植物激素对生长的影响。然后，我们选择了 27 个已知在木材形成中具有作用的基因进行 qPCR 分析，以确定其对植物激素处理的组织特异性和时间响应。与对照相比，大多数 IAA、GA₃ 和 BR 浓度显著增加了幼苗的高度。同时，IAA 诱导了幼苗茎直径和纤维素含量的显著增加，分别在 3 和 30mg·L 时达到峰值。在 100mg·L GA₃ 处理的幼苗中也观察到纤维素含量的显著增加。BR 处理对幼苗茎直径和纤维素含量均无显著影响，尽管有轻微影响。解剖学测量表明，IAA 和 BR 处理的幼苗木质部发育得到改善，但韧皮部发育没有改善。IAA、GA₃ 和 BR 诱导的大多数基因表达模式在组织间存在差异。许多 IAA 响应基因也受 GA₃ 调控，而 BR 诱导的转录在 中的作用比 IAA 和 GA₃ 弱且慢。这些结果揭示了植物激素在植物生长中的作用，并为探索 中木材形成的分子调控机制奠定了基础。
