Gametophyte Development of the Moss Bartramia pomiformis under in Vitro Culture Condition

The present studies were conducted to develop a mass micropropagation system for Bartramia pomiformis. Spores of B. pomiformis were germinated in vitro and gametophytic development was examined by observing development of primary and secondary protonema. In vitro cultures of indehiscent mature spores yielded primary protonema and suspension cultures of gametophytes secondary protonema. Distinctive bud development of gametophytes was obtained from comparative studies of primary and secondary protonema. The time taken for bud induction was shorter in secondary protonema. After the transition of chloronema, the highest percentage of caulonema was observed from secondary protonema. Caulonemae from a secondary protonema were thicker-walled and darker than those from primary protonema when grown on the same media. During the differentiation stage, bud induction formed three-faced apical cells for primary protonema and multi-faced for secondary protonema. Gametophytes also produced gemmae, rhizoid and stoloniferous caulonema as specialized propagules. The most pertinent morphological finding in these studies was that it took different amounts of time for growth of single caulonema strands and for bud initiation.