Corbesier Laurent, Prinsen Els, Jacqmard Annie, Lejeune Pierre, Van Onckelen Harry, Périlleux Claire, Bernier Georges
Department of Life Sciences, Laboratory of Plant Physiology, University of Liège, B22 Sart Tilman, B-4000 Liège, Belgium.
J Exp Bot. 2003 Nov;54(392):2511-7. doi: 10.1093/jxb/erg276. Epub 2003 Sep 25.
Understanding the complete picture of floral transition is still impaired by the fact that physiological studies mainly concern plant species whose genetics is poorly known, and vice versa. Arabidopsis thaliana has been successfully used to unravel signalling pathways by genetic and molecular approaches, but analyses are still required to determine the physiological signals involved in the control of floral transition. In this work, the putative role of cytokinins was investigated using vegetative plants of Arabidopsis (Columbia) induced to flower synchronously by a single 22 h long day. Cytokinins were analysed in leaf extracts, leaf phloem exudate and in the shoot apical meristem at different times during floral transition. It was found that, in both the leaf tissues and leaf exudate, isopentenyladenine forms of cytokinins increased from 16 h after the start of the long day. At 30 h, the shoot apical meristem of induced plants contained more isopentenyladenine and zeatin than vegetative controls. These cytokinin increases correlate well with the early events of floral transition.
由于生理学研究主要关注那些遗传学背景了解甚少的植物物种，反之亦然，因此对花期转变全貌的理解仍然存在障碍。拟南芥已成功用于通过遗传和分子方法揭示信号通路，但仍需要进行分析以确定参与花期转变控制的生理信号。在这项研究中，使用经单次22小时长日照诱导同步开花的拟南芥（哥伦比亚型）营养植株，研究了细胞分裂素的假定作用。在花期转变的不同时间，对叶片提取物、叶片韧皮部渗出液和茎尖分生组织中的细胞分裂素进行了分析。结果发现，在叶片组织和叶片渗出液中，细胞分裂素的异戊烯腺嘌呤形式从长日照开始后16小时起增加。在30小时时，诱导植株的茎尖分生组织中所含的异戊烯腺嘌呤和玉米素比营养对照组更多。这些细胞分裂素的增加与花期转变的早期事件密切相关。
