灰叶胡杨根蘖繁殖的形态解剖学特征

利用常规石蜡切片法对灰叶胡杨(Populus pruinosa)根蘖繁殖特性进行形态解剖学研究。结果表明: 灰叶胡杨横走侧根由周皮、次生维管组织和四原型的初生木质部构成, 具有次生维管组织中维管射线、次生韧皮薄壁组织发达的结构特征。灰叶胡杨的根蘖繁殖源于横走侧根上不定芽的发生及生长发育。不定芽起源于横走侧根的木栓形成层, 木栓形成层经细胞分裂活动形成不定芽原基, 不定芽原基细胞分裂和生长分化形成在横走侧根表面可观察到的不定芽, 进而生长发育为根蘖苗。不定芽的发生具有同步或非同步的时间特征和单点或多点聚集的空间分布特点, 在生长发育过程中其基部可以产生新的不定芽。不定芽发生、分布和生长特点是根蘖苗大小不一、密集丛生的内在原因, 表明灰叶胡杨具有较强的根蘖繁殖能力。

Morphological and Anatomical Features of Root Sucker Propagation of Populus pruinosa

We studied the morpho-anatomic characteristics of the clonal growth of root suckers of Populus pruinosa by the conventional paraffin method.Transverse lateral roots were formed by periderm,secondary vascular tissue,and the tetrarch’s primary xylem,with developed vascular rays and secondary elongated parenchyma in secondary vascular tis-sues.The clonal growth of root suckers of P.pruinosa is based on the development and growth of adventitious buds on transverse lateral roots.Adventitious buds originated from cork cambium of transverse lateral roots and expressed the time characteristics of synchronous and asynchronous generation and the spatial characteristics of single-point and multi-point gathered generation.The cork cambium cells formed primordia of adventitious buds by cell division.The cell division,proliferation,and differentiation of adventitious primordia formed visible primordia on the surface of transverse lateral roots and directly developed as root suckers.The features of adventitious bud development,distribution,and growth were the key reason for root suckers to keep growing to different sizes and form a densely fasciculate shape.P.pruinosa has good ability for clonal growth of root suckers.