林业科学2016，Vol.52Issue(10)：38-44,7.DOI:10.11707/j.1001-7488.20161005
光皮桦应拉木的显微特征及其形成早期内源激素分布
Xylem Characteristics of Tension Wood and Endogenous Hormones Distributions during Its Early Formation Period in Betula luminifera
摘要
Abstract
Objective]Reaction wood is one of the limiting factors for efficient cultivation and wood utilization of fast-growing timber species. There are various types of tension woods ( TWs) in Betula luminifera plantation,but the research on their characteristics and forming causes is absent. In this study,microscopic structure,physical and chemical characteristics of B. luminifera TW were determined,and distributions of endogenous hormones were analyzed during the early period of its formation to provide knowledge of the TW formation mechanism in birch.[Method]B. luminifera clone 1V25-2 was used for artificially inducing tension wood by bending. Anatomical characteristics of xylems were observed,and fiber characteristics, microfibril angle,and contents of cellulose and lignin were determined. The distributions of four endogenous hormones were analyzed using the ELISA during the early period of TW formation ( from 6 h to 7 d of a tension time course) .[Result]TWber presented a conspicuously thickened inner layer of the cell wall after bending for 12 months,and the fiber of the double wall was averagely 1. 8 times more thickness than the opposite wood (OW) fiber. The double-stained results with Safranin-Astra blue showed that a gelatinous layer deposited in the lumen side of secondary cell wall of TW. Fiber lengths and cellulose contents of TW were both obviously greater than those of OW,but lignin contents exhibited the converse tendency. At the early stages of bending treatment,four endogenous hormones showed the distinct distributions in different xylem regions. The IAA content of TW was all lower than that of OW,but the difference between the two regions reached to significant level only after 7 days bending. The distributions of GAs ( GA1 +GA3 ) were same as IAA. Except for the sample of 6 h bending,the BR contents of OW were significantly higher than those of TW,and showed a rising tendency as bending progressed. Although ZR content showed a rising tendency as bending progressed,their differences between TW and OW were insignificant for each sampling time. However,the ZR content of TW and OW was significantly higher than that of the control after 7-day of bending.[Conclusion]After 12 months bending,cell walls of B. luminifera were obviously thickened in TW xylem. A typical gelatinous layer was deposited in the lumen side of secondary cell wall of this region. And specific physical and chemical characteristics,such as the longer fibers and higher cellulose content,were found in TW. At the early stages of bending,four endogenous hormones showed the different distribution patterns in the xylems,implying that re-distributions of these hormones may be associated with the TW formation in B. luminifera.关键词
光皮桦/应拉木/显微特征/理化特性/内源激素/分布规律Key words
Betula luminifera/tension wood/anatomical characteristics/physicochemical properties/endogenous hormones/distribution regulations分类
农业科技引用本文复制引用
何辉,楼雄珍,林二培,俞友明,童再康,黄华宏..光皮桦应拉木的显微特征及其形成早期内源激素分布[J].林业科学,2016,52(10):38-44,7.基金项目
国家自然科学基金项目(31470674) （31470674）
浙江省农业科技重点项目(2012C12908－8) （2012C12908－8）
浙江省林学一级重中之重学科学生创新计划项目(201526)。 （201526）
