Seasonal variation in desiccation tolerance in some British bryophytes

Abstract

Six bryophyte species were investigated: Plagiochila spinulosa, Hylocomium splendens, Scorpiurium circinatum, Tortula ruraliformis, Rhacomitrium aquaticum and Andreaea rothii. Of these, all except A. rothii showed clear evidence of seasonal variation in desiccation tolerance, as measured by net assimilation following 24 h remoistening.

(2) In general these species showed low desiccation tolerance in autumn (October) and winter (January) and increased tolerance in spring and summer. Hylocomium splendens was a partial exception in showing relatively high tolerance in January and little change from then until July.

(3) On the whole, the seasonal pattern of desiccation response accords well with what might be expected from conditions in the habitats of the plants. The results are briefly discussed in relation to distribution of rainfall and some microenvironmental factors, and compared with some data from the literature.