Abstract:

Viviparous reproduction is a beneficial supplement to spore reproduction of pteridophytes， which enriches the reproduction and regeneration system and affects the population genetic diversity and environmental adaptability. In this study， Cystopteris chinensis， a national key protected wild plant， was selected as materials， and morphological and anatomical methods were used， the morphological and anatomical characteristics of the gemmae with the unknown process behind the pinna were examined， and the reproductive structure and development process were revealed， and the viviparous origin and ecological adaptation mechanism of the gemmae were traced. The results showed that： （1）The gemmae and sporangium groups appeared in the middle of the last veins on the abaxial leaf pinna， but the gemmae were located in the apical pinnate lobes. The gemmae formation included three stages： initiation， expansion and maturation， the gemmae gradually grew from yellow-green globule to dark green spindle-shaped， and matured when the base turned black to form a separate layer. （2）The gemmae originated from the parenchyma cells in the extension area of the vascular bundle sheath， which continuously divided and grew to form the gemmae primordium， and gradually broke through the lower epidermis of the leaf to form spherical gemmae. With the gemmae expansion， the middle and lower cells differentiated into storage cells and vascular bundles， and the apex differentiated into growth points to form buds. （3）Few gemmae could directly sprout on the leaves to form new autotrophs. After falling to the soil for 1 week， the mature gemmae began to germinate， which grew cylindrical roots at the base， and the fist bud germinated at the top. The residual gemmae still germinated into new leaves in the second year， which were different from those produced by stem buds.

Key words: Cystopteris chinensis, gemmae, anatomical structure, vegetative viviparity