Abstract Detail

Bryology and Lichenology

Clark, Theresa [1], Stanton, Daniel [2].

Vapor hydration awakens tough mosses after 5 years of dry storage.

Natural precipitation events are usually preceded by a gentle rise in humidity over multiple hours before rainfall begins. It has been predicted that this increasing humidity prepares the desiccated tissues of poikilohydric species like mosses for an otherwise damaging inrush of liquid water when rain contacts their dry, absorbent leaves. While several studies have observed positive recovery effects of vapor exposure post-desiccation, no studies have tested the timing of photosynthetic activation to elucidate the protective vapor mechanism. To this end, we attempted to resurrect 23 species of dryland mosses (Pottiaceae) that had been dried for five years in an herbarium. We exposed the treatment group to high humidity for two days prior to liquid water introduction and measured photosynthetic activation and recovery using imaging fluorescence (Fv/Fm) over one week. Controls were hydrated directly with liquid water. Most species survived the "wakeup experiment" with or without vapor hydration, but vapor ellicited an earlier photosynthetic activation in many species which effectively lead to faster recovery of maximum efficiency in Photosystem II (imaging fluorescence, Fv/Fm). All surviving specimens were able to produce new shoots in a test of long-term viability, which did not differ by treatment. Results suggest that vapor exposure speeds recovery via early photosynthetic activation which initiates before the introduction of liquid water. Therefore, our results (1) challenge previous speculation that vapor exposure reduces intracellular damage and (2) conversely, illustrate how vapor creates an "early wake-up" before precipitation rather than a “gentle wakeup”.

1 - University of Minnesota - Minneapolis, MN, Ecology, Evolution, & Behavior, Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN, 55108, United States
2 - University Of Minnesota, Ecology, Evolution And Behavior, 1479 Gortner Ave, Saint Paul, MN, 55108, United States

Keywords:
Bryophyte
vapor hydration
desiccation tolerance
Imaging fluorescence
Syntrichia.

Presentation Type: Oral Paper
Number: BL2006
Abstract ID:1061
Candidate for Awards:None