Mohria caffrorum (L.) Desv. : a new, unique model organism for the study of desiccation tolerance

Vegetative desiccation tolerance is the ability of a plant to dry to equilibrium with its surrounding atmosphere and remain in this dry state for prolonged periods of time. Upon rehydration, these plants are able to regain full physiological functionality. Vegetative desiccation tolerance is common and partially understood in the less complex clades including the algae, bryophytes and lichens but is uncommon in the vascular land plants. Vegetative desiccation tolerance is partially understood in the angiosperms but there has been little work on desiccation tolerance in pteridophytes Mohria caffrorum (L.) Desv is one such desiccation tolerant pteridophyte This fern has the unique characteristic of having both desiccation tolerant and desiccation sensitive forms, which alternate seasonally, which this study is the first to show. We show here that; 1) M caffrorum is indeed a desiccation tolerant fern. 2) M. caffrorum has desiccation tolerant and desiccation sensitive frond types. which are morphologically distinct. 3) These morphological differences are directly related to the ability to survive desiccation as well as playing a role in tine ecologies of the two growth forms. 4) The spores of M. caffrorum are also desiccation tolerant. A hypothesis is proposed detailing why M. caffrorum is able to change between being desiccation tolerant and desiccation sensitive