The pattern of recovery of bryophytes after desiccation

(1) Net assimilation and respiration rates were measured at intervals after re-moistening, following various periods of desiccation, in Hookeria lucens, Hylocomium splendens, Neckera crispa, Plagiochila spinulosa, Plagiothecium undulatum, Rhacomitrium lanuginosum, Rhytidiadelphus loreus, Saccogyna viticulosa, Scorpiurium circinatum and Tortula ruraliformis.(2) Rhacomitrium lanuginosum was extremely resistant, recovering apparently normally after 239 days' desiccation at 32% R.H.; Plagiochila spinulosa and Hookeria lucens were the most sensitive.(3) Rhacomitrium lanuginosum and Tortula ruraliformis were most quickly damaged at the highest humidity (76%) and Plagiothecium undulatum at the lowest humidity tested (32%).(4) Saccogyna viticulosa and Scorpiurium circinatum combined relatively rapid impairment and slow recovery of assimilation with the capacity to survive long dry periods.(5) Dark respiration was relatively slow (commonly c. 5–20% of net assimilation). It usually showed a slight initial stimulation and a longer-term build-up following moderate or prolonged desiccation.(6) Desiccation responses of bryophytes can be characterized in terms of parameters defining rate of loss of photosynthetic capacity with desiccationtime, rate of recovery after short periods of desiccation, and survival.