Gametophyte Development and Sporophyte Formation of the Fern Osmunda japonica in Two Culture Media

The gametophyte development and sporophyte formation cultured on agar and humus media were studied using microscopical techniques.(1)The spores are green,tetrahedral,and trilete.The polar germination of spore leads to produce a primary rhizoid and a prothallial cell.The prothallial cell develops into the sphere,plate and then matured gametophyte(adult prothallus),respectively.(2)The matured gametophytes are distinguished as the male,female or hermaphroditic prothallia.The male gametophytes are usually small and produce antheridia in the basal of their wings.The female gametophytes are usually large and produce archegonia in the lateral side of the midrib.There is only one archegonium in each prothallus which can be fertilized and develops into embryo and sporophyte.(3)The matured gametophytes and sporophytes can be obtained in the two different culture media.However,the gametophytes develop fast on agar medium.But the viability of sporophytes obtained on this medium is weak and difficult to transplant.The gametophytes develop slowly on humus medium.But the viability of sporophytes obtained on this medium is strong and easy to transplant.In addition,the gametophyte can survive for a long time and produces new gametophytes through vegetative propagation.