中国苏铁属花粉形态研究

对中国苏铁属花粉进行了光镜和扫描电镜观察。花粉中等大，极轴长２６．５－３５．７μｍ，赤道轴长２０．６－２６．４μｍ；极面观椭圆形至近圆形，赤道面观船形或肾形，具远极单沟，达两端，其开闭和形状随花粉干燥或潮湿而变化，内部具多种不规则突起，两端具皱纹；远极面外壁光滑或稀具微突起，近极面具穿孔，孔穴或蜂窝状纹饰。

ASTUDYOFPOLLEN MORPHOLOGY OF THE GENUS CYCASFROM CHINA

The pollen morphology of the genus Cycas from China has been investigated under LMand SEM. The pollen grains are ofmedium size,with polar axis 26.5-35.7um, and equatorial ax-is 20.6-26.4um in length.In shape they are elliptic or circular on AMB, and boat- orkidney-shaped on eq uatorial contour,with a single deep and longitudinal furrow reaching fromend to end on distal face.The opening or closure ofthe furrows and pollen shape change when thgrains are dry or moistened.The inner surface of the furrows are ofter wringled with strips.Thedistal surface are smooth or rarely minutely warty while on the opposite face it is perforate offoveolate. The interspecific differences are very obscure,implying a natural group of Cycas. Thegenus Cycas is similar to other genera of cycads in pollen morphology.Similar pollen type is foundonly in the genus Ginkgo. Their pollen resemblence implys that their relationship is possibly closerthan cvcads with other extant taxa ofg ymnospems.