ibclogo XVI International Botanical Congess


Abstract Number: 5125
Session = 12.17.2


THE BRYOPHYTE PARADOX: TOLERANCE OF DESICCATION, EVASION OF DROUGHT


M. C. F. Proctor, University of Exeter, UK.


Bryophytes in general have adapted to the intermittent availability of water on land by evolving desiccation tolerance. Gas-exchange and chlorophyll-fluorescence measurements show that recovery from desiccation is often largely complete within 15-20 minutes. This fast initial recovery is independent of protein synthesis, and is commonly accompanied by a peak of xanthophyll-cycle related NPQ. Desiccation-tolerant bryophytes typically have external water conduction and storage, most of the water associated with the plants can be lost before cell function is affected. Most of the time the cells are either functioning at full turgor, or are dry and metabolically inactive. Typical vascular-plant drought responses and metabolites are notably absent in ry habitat bryophytes, which are all C3 plants generally with relatively low light-saturation levels.


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