In vitro studies of two drought tolerant bryophytes

Abstract

Bryophytes constitute a group of non-vascular plants that include mosses, liverworts and hornworts. Our research group has initiated the search and study of Mexican bryophyte species that have high levels of drought tolerance. Mature gametophytes and sporophytes of the moss Ceratodom stenocarpus and the hepatic Targionia hypophylla were collected before the rainy season at a Juniperus forest localized in Tlaxcala state. Phenotypic analyses under water-deficit conditions showed that these species can withstand a total loss of water content from their cell protoplasm, but they can also rehydrate rapidly after watering. Thus, the selected bryophytes present clear characteristics of the resurrection phenomenon (desiccation tolerance). Spores obtained from superficially disinfected sporophytes were used to perform germination in vitro assays in the presence and absence of salt (NaCl) and osmotic agents at different concentrations. To investigate the effect of salt and osmotic stress on adult stages, we focused experiments on transferring mature tissues to stressing plates. The obtained results showed that both studied species are osmotic stress tolerant but salt sensitive plants at both germination and mature stages of development.