Regeneration responses differ among three boreal mosses after exposure to extreme temperatures

Abstract

Many factors may affect the survival and establishment of a moss’s vegetative propagules after dispersal, but little is known about the species-specific nature of the response. This study examined the survival and regeneration of gametophore fragments after exposure to temperature changes for three boreal forest mosses from different habitats: Dicranum polysetum, Orthotrichum obtusifolium, and Pleurozium schreberi. Fragments were cultured on water agar and the survival and regeneration responses were recorded. Logistic regression analyses and AIC modeling evaluated the association between the response with the size of the gametophore fragments exposed to five abrupt or gradual temperatures for up to six exposure durations. The increased survival and regeneration was best explained when species were exposed to gradual, rather than abrupt temperatures; lower, rather than higher temperatures; and when the fragments had larger, rather than smaller sizes. The mosses had different survival and regeneration responses that may be species-specific, including clonal growth via the production of gametophore branches and protonemata, or mostly protonemata, even when exposed to elevated temperatures.