首页 | 本学科首页   官方微博 | 高级检索  
     


Role of auxin and gibberellin in regenerative differentiation of tracheids in Pinus pinea seedlings
Authors:NATALIE KALEV,&   RONI ALONI
Affiliation:Department of Plant Sciences, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; To whom correspondence should be addressed. E-mail:
Abstract:A new experimental system was developed for studying the hormonal mechanisms which control tracheid differentiation. In this system the tracheids redifferentiated from parenchyma cells in the hypocotyl of young Pinus pinea L. seedlings. The experimentally induced tracheids have unique shapes and patterns, and are therefore easily distinguished from the primary and secondary tracheids formed before the experiments. Auxin (0·1–1% NAA) alone sufficed to cause the redifferentiation of short tracheids, usually in discontinuous patterns across the hypocotyl. Gibberellin by itself did not induce redifferentiated tracheids. Combinations of auxin with gibberellin (0·1% NAA+0·1–1% GA3) promoted the differentiation of long tracheids (up to threefold greater than those induced by auxin) in continuous patterns along the stem axis. Gibberellin in the presence of auxin promoted tracheid elongation by stimulating intrusive growth of both the upper and lower ends of the differentiating tracheids. The role of auxin and gibberellin in controlling the evolution of tracheary elements, from tracheids to vessels and fibres, is discussed.
Keywords:Phytohormones (auxin, gibberellin)    Pinus pinea L. (pine)    tracheid differentiation    xylem (regeneration, evolution)
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号