Desiccation-tolerant (DT) bryophytes are exposed to frequent dehydration/rehydration
cycles.
The variability and time course of the regenerative and repair mechanism activated
upon
rehydration are significantly determined by the intensity and duration of the desiccation
episode. Because of the unknown physiological history of field-collected plants, before
laboratory tests on desiccation tolerance (also abbreviated as DT), the plants should
be fully
dehardened by allowing through a state of uninterrupted hydration under nonstressful
conditions. This work used field-collected bryophytes for the study of desiccation
tolerance
with particular attention to the deacclimation (dehardening) of plants, rate of desiccation,
and
water content. It also takes into account the ecological factors of rehydration and
the
physiological processes that take place and contribute to regeneration. DT is a variable
plastic
trait in some bryophytes, which increase or decrease DT in response to environmental
cues
such as previous drying. The plasticity of DT response means the potential reversibility
of
acclimation and deacclimation to DT. Bryophyte species that can tolerate drying, at
any rate,
are known as “fully DT”. Several issues remain to be clarified about regeneration
after
dehydration.
