莲幼苗初生维管系统研究

莲（Ｎｅｌｕｍｂｏ ｎｕｃｉｆｅｒａ Ｇａｅｒｔｎ．）幼苗属无根型。子叶片下部愈合呈筒状,并和子叶节区及其下部愈合为一体。子叶节区下部维管柱为χ形单中柱;子叶节区中部为周韧单中柱,子叶迹呈６束辐射均匀地进入子叶;子叶节区上部为散生中柱,其央的４－６个大维管束由子叶节区中部的单中柱分裂形成;周围的小维管束一部分由子叶迹分裂形成,一部分由周围薄壁细胞脱分化形成。

Studies on the Primary Vascular System of the Seedling of Nelumbo nucifera

Nelumbo nucifera Gaertn. has a no-radicle seedling. The lower part of the cotyledon lamina fuses into a tube-shaped object, and comes into an integrity with the cotyledon node zone (CNZ) and the part below it. The lower part of CNZ has a χ-shape haplostele. The middle part has a haplostele with the xylem enclosed by the phloem. The six vascular bundles of the cotyledon trace extend into the cotyledon radiantly and evenly. The haplostele of the middle part of CNZ is separated into 4～6 big vascular bundles which were in the central part of the atacto-stele in the upper part of CNZ. Part of the small vascular bundles of the atacto-stele originats from the division of the cotyledon trace, and the other comes from redifferentiation of the surrounding parenchyma cells.