Cox Marjolein C H, Peeters Anton J M, Voesenek Laurentius A C J
Plant Ecophysiology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, the Netherlands.
Plant Cell Environ. 2006 Feb;29(2):282-90. doi: 10.1111/j.1365-3040.2005.01420.x.
The flooding-tolerant plant species Rumex palustris (Sm.) responds to complete submergence with stimulation of petiole elongation mediated by the gaseous hormone ethylene. We examined the involvement of auxin in petiole elongation. The manipulation of petiolar auxin levels by removing the leaf blade, or by addition of synthetic auxins or auxin transport inhibitors, led to the finding that auxin plays an important role in submergence-induced petiole elongation in R. palustris. A detailed kinetic analysis revealed a transient effect of removing the auxin source (leaf blade), explaining why earlier studies in which less frequent measurements were taken failed to identify any role for auxin in petiole elongation. We previously showed that the onset of stimulated petiole elongation depends on a more upright petiole angle being reached by means of hyponastic (upward) curvature, a differential growth process that is also regulated by ethylene and auxin. This raised the possibility that both ethylene and auxin stimulate elongation only indirectly by influencing hyponastic growth. We show here that the action of ethylene and auxin in promoting petiole elongation in submerged R. palustris is independent of the promoting effect that these hormones also exert on the hyponastic curvature of the same petiole.
耐水淹植物物种沼生酸模（Rumex palustris (Sm.)）在完全淹没时，会通过气态激素乙烯介导的叶柄伸长刺激做出反应。我们研究了生长素在叶柄伸长中的作用。通过去除叶片、添加合成生长素或生长素运输抑制剂来控制叶柄生长素水平，结果发现生长素在沼生酸模淹没诱导的叶柄伸长中起重要作用。详细的动力学分析揭示了去除生长素来源（叶片）的短暂效应，这解释了为何早期测量频率较低的研究未能确定生长素在叶柄伸长中的任何作用。我们之前表明，刺激叶柄伸长的开始取决于通过偏下（向上）弯曲达到更直立的叶柄角度，这是一个也受乙烯和生长素调节的差异生长过程。这就提出了一种可能性，即乙烯和生长素都仅通过影响偏下生长间接刺激伸长。我们在此表明，乙烯和生长素在促进淹没的沼生酸模叶柄伸长中的作用，独立于这些激素对同一叶柄偏下弯曲的促进作用。
