黄柳不同级序根的解剖结构及其细根的研究

采用石蜡切片法和徒手切片法对3年生黄柳不同级序的根进行解剖结构研究,并结合直径和根序对其细根进行定义,为沙生植物细根及其碳分配等相关研究提供依据。结果表明:(1)黄柳1、2级根为初生根,4、5级根为次生根,3级根为过渡型根。(2)黄柳根的初生木质部为三原型或四原型。(3)黄柳不同级序根的形态与解剖结构存在显著差异,随着根序的增加,根直径与维管柱直径逐渐增大;低级根直径主要影响因素为维管柱直径、皮层薄壁细胞直径和皮层层数;高级根直径主要影响因素为维管柱直径。(4)定义黄柳的细根为前3级根中未形成连续木栓层且直径小于0.7mm的根。该研究明确了黄柳不同级序根的解剖结构特征,并界定了黄柳细根的范围,其研究方法对于精确估计细根在生态系统中的作用具有重要的意义。

Anatomical Characteristics of Roots with Different Orders and Fine Root of Salix gordejevii

We studied on the anatomical characteristics of roots with different orders of Salix gordejevii by paraffin and hand-sliced methods,and defined its fine root combining with the diameters and root orders.The results showed that:(1)The first and the second order roots had only primary growth.The fourth and the fifth order roots had secondary growth.Some of the third order roots had primary growth,but some had secondary growth.(2)The primary xylem was triarch or tetrarch.(3)There were significant differences in root morphology and anatomy of different orders of S.gordejevii.With the increase of the root order,the diameters of roots and vascular cylinder increased.The diameters of lower roots were mainly influenced by vascular cylinder diameters,the diameters of cortical parenchyma cells and cortical layers,and the diameters of senior roots were mainly affected by vascular cylinder diameters.(4)We defined the fine roots of S.gordejevii that should do not form successive phellogen among the first and the third root orders and have diameters less than 0.7 mm.The anatomical characteristics and fine root of roots among different orders of S.gordejevii were determined.The research was provided a reference for the studies on the fine roots and the carbon allocation of psammophyte.The method we used was important to accurately estimate the function of fine roots in the ecosystem.