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The desert moss Pterygoneurum lamellatum (Pottiaceae) exhibits an inducible ecological strategy of desiccation tolerance: Effects of rate of drying on shoot damage and regeneration
Premise of the study: Bryophytes are regarded as a clade incorporating constitutive desiccation tolerance, especially terrestrial species. Here we test the hypothesis that the opposing ecological strategy of desiccation tolerance, inducibility, is present in a desert moss, and addressed by varying rates of drying in a laboratory study. Methods plants were cloned, grown in continuous culture (dehardened) for several months, and subjected to rates of drying ranging from 30 min to 53 h, rehydrated and tested for recovery using chlorophyll fluorescence, leaf damage, and regeneration of protonema and shoots. Key results: Rate of drying significantly affected all recovery responses, with very rapid drying rates severely damaging the entire shoot except the shoot apex and resulting in slower growth rates, fewer regenerative shoots produced, and a compromised photosynthetic system as inferred from fluorescence parameters. Conclusions: For the first time, a desert moss is shown to exhibit an ecological strategy of desiccation tolerance that is inducible based upon the rate of prior drying, thus challenging the assumption that aridland bryophytes rely exclusively on constitutive protection from desiccation. A technique is presented that allows a separation of rate of drying from equilibrating relative humidity, and which removes site (field) effects and age heterogeneity from shoots. Results indicate that previous considerations defining a slow-dry event in bryophytes need reevaluation, and that the ecological strategy of inducible desiccation tolerance is probably more common than currently understood among terrestrial bryophytes.
Melvin J Oliver
desiccation (plant physiology)
mosses and liverworts
American journal of botany 2013 v.100 no.8
Journal Articles, USDA Authors, Peer-Reviewed
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Agricultural Research Service
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