Vitamin B12-stimulated growth and development of Jungermannia leiantha Grolle and Gymnocolea inflata (Huds.) Dum. (Hepaticae)

Exogenous vitamin B,2 supplied to axenically cultured gametophytes of Jungerman- nia leiantha Grolle (Jungermanniaceae) and Gymnocolea inflata (Huds.) Dum. (Lophoziaceae) significantly stimulated growth in both species. Pink-pigmented, facultative methylotrophic bacteria, which synthesize and accumulate vitamin B,2, have been regularlyfound associated with bryophytes. Our findings and those of others cited herein indicate that if the vitamin B2, synthesized by these bacteria, or from any other source, should become available, bryophytes and other embryophytes could benefit.