Ecological Responses of Bryophytes to Changing Climate
Tuba, Zoltán .
Ecophysiology of mosses under elevated air CO2 concentrations: an overview.
THIS paper summarises the ecophysiological responses of bryophytes to elevated atmospheric CO2 concentrations. Bryophytes are belonging to the most prominent groups of desiccation-tolerant (DT) photosynthetic organisms. Recent synthetic phylogenetic analyses suggest that vegetative desiccation tolerance was primitively present in the bryophytes (the basal-most living clades of land plants), but was then lost in the evolution of tracheophytes. Variations in atmospheric CO2 concentration are nothing new: CO2 concentrations were higher or lower during some earlier geological periods. Bryophytes as ancient land C3 plants experienced these changes of CO2 concentrations in air. Results of research on bryophytes are compared with those on desiccation sensitive and evolutionary younger vascular C3 plants, the most widely investigated group in the field of global change. The present ambient CO2 concentration can be suboptimal for bryophytes and for other land plants,. Therefore both bryophytes and non-DT vascular plants show an immediate positive response of photosynthesis to elevated CO2, but in both groups the longer term effect is generally reduced or even reversed by down-regulation or negative feedback inhibition of photosynthesis, or other limitations on growth/production. In bryophytes enhanced short-term photosynthesis may or may not be reflected in increased production because bryophytes have limited source-sink differentiation. Negative, downward acclimation of photosynthetic system in bryophytes can also be detected. However bryophytes as DT plants may gain some advantage from elevated CO2 at both low and excessive water contents. Neither theoretical considerations nor experimental results suggest that elevated atmospheric CO2 will lead to any substantial shift in the balance of advantage between DT bryophytes and non-DT plants.
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1 - Szent István University, Faculty of Agricultural & Environmental Sciences, Department of Botany & Plant Physiology, Páter K. u. 1., Gödöllő, H-2103, Hungary
Presentation Type: Symposium or Colloquium Presentation
Date: Monday, July 31st, 2006
Time: 8:45 AM