石山苏铁与锈毛苏铁羽片解剖学研究

ANATOMICAL STUDIES ON PINNA E OF CYCAS MIQUELII AND C.FERRUGINEA

摘要:

研究了石山苏铁与锈毛苏铁叶的羽片横切面结构。结果表明,石山苏铁叶表面具厚的角质层,表皮细胞壁厚,排成整齐的一列;下皮层厚壁细胞仅分布于中脉隆起区和叶缘;叶肉由栅栏组织和海绵组织构成,栅栏组织为排列整齐的柱状细胞组成,位于近轴面的表皮层下方,并延伸至中脉区;海绵组织的细胞分布于副转输组织两侧,含晶细胞少;韧皮部在远轴面,排成弧形;木质部在近轴面,管胞分散。锈毛苏铁的羽片横切面结构在叶缘的形态、叶脉区隆起形态、韧皮部形态、分泌道有无及下皮层厚壁细胞的特点等方面与石山苏铁存在较明显的差异。本文支持把两者作为独立种的观点。

Abstract:

In order to make sure whether Cycas miquelii and C．ferruginea are of the same species，the authors have observed an atomically the two species．The results show that the leaf surface of C. miquelii covered with thick cuticle． Wall of epidermal cell is thick and arranged regularly in one layer．Hypodermal sclerenchyma cells exist in the raised midrib region and pinna margins．Mesophyll consists of patisade and spongy tissues．Palisade tissue is composed of cylindrical cells being regularly arranged，beneath adaxial hypodermis and present above the midrib． The cells of spongy tissue are distributed at the two sides of the accessory transfusion tissue．Crystal cells are few．The phloem locates on abaxial side and is arranged in arch shape，while the xylem on adaxial side．Tracheids are scattered．Cucas miquelii is obviously different from C. ferruginea in structure in transverse section, such as the shapes of pinna margin，raised midrib region and hypodermal sclerenchyma cells． Based on such difference between C. miquelii and C. ferruginea，the authors consider that they are separate species．