甘肃窑街中侏罗世Coniopteris lanzhouensis的微细构造研究

STUDY ON THE MICROSTRUCTURE OF THE MIDDLE JURASSIC CONIOPTERIS LANZHOUENSISFROM YAOJIE,GANSU PROVINCE,CHINA

本文对甘肃窑街中侏罗统窑街组采集的真蕨类化石标本进行了描述,通过与相似种的小羽片的形态和大小、羽片排列和间距、羽轴宽度、孢子囊群形态等特征对比,明确该化石植物为Coniopteris lanzhouensis。通过实验分析揭示了Coniopteris lanzhouensis的原位孢子基本特征:孢子为四面体,赤道轮廓呈圆三角形,顶角钝圆,三边线微凸或微凹;具三射线,三射线平直且较窄,长度为孢子半径的3/4或延伸至孢子边缘,顶端具与其垂直的褶皱;外壁光滑,壁薄,极面观直径30-40μm,平均约33μm;孢子的颜色以浅黄色为主。明确了Cibotiumspora juncta可能是Coniopteris lanzhouensis的孢子,后者为前者的母体植物。

A fossil fern is described, from the Middle Jurassic Yaojie Formation in Gansu Province, NW China. By comparing its characteristics such as shape and size of pinnules, the arrangement and distance of pinna, the width of rachis, the morphology of sorus with several species that belong to the genus Coniopteris and the fossil plant are identiffed as Coniopteris lanzhouensis. In situ spores of Coniopteris lanzhouensis are tetrahedral spores; equatorial con tour is a rounded triangular, obtuse-rounded apex angle; three edges are slightly convex or slightly concave, with three straight and narrow rays which are 3/4 length of radius or almost reaching the edge of the spore. There are some vertical folds at the top of it; the exine is smooth and thin, the diameter of spore in polar view ranges from 30 to 40 μm and the average is about 33 μm; the color of spore is mainly pale yellow. The present study indicates that Ci- botiurnspora juncta is the spore of Coniopteris lanzhouensis, i. e. the latter is the parent plant of the former.