INDUCED APOSPORY IN THE LIVERWORT BLASIA PUSILLA

Immature sporophytes of Blasia pusilla L. collected in the field were excised from the protective gametophytic tissues and cultured on a slightly modified Knop's agar substrate in microphytotrons. Under the experimental conditions the setae elongated and after 33½ to 6 weeks many began to give rise to from 1 to 20 or more aposporous outgrowths. These subsequently developed into young gametophytes. The apices were then cut off, sterilized, and grown on glucose-mineral agar in aseptic culture. The resulting gametophytes were similar to haploid plants derived from spores in pattern and rate of growth, and in possession of rhizoids, ventral scales, lateral lobes, auricles, and stellate and discoid gemmae. They produced archegonia but no antheridia. The chromosome number of the aposporous plants was 18 in contrast to the normal haploid number of 9.