Sporophyte desiccation tolerance in the moss Aloina

Ecological strategies of desiccation tolerance in plants vary along a continuum from highly inducible to highly constitutive. Stark and Brinda study cultured sporophytes and vegetative shoots from a single genotype of the moss Aloina ambigua and find that the gametophytes and embryonic sporophytes employ a predominantly inducible strategy of desiccation tolerance, while the post-embryonic sporophytes employ a moderately constitutive strategy of tolerance. The transition from inducible to constitutive occurs over a period of just 2 days, and represents only the second time such a shift has been shown in a plant and the first time it has been observed in a bryophyte. Desiccation tolerance in mosses may therefore be an either/or phenomenon that varies in degree along a gradient of ecological inducibility.