Abstract Detail



Bryology and Lichenology

Ebrahimi, Sotodeh [1].

Light conditions during desiccation and rehydration impact the recovery of field-hardened moss shoots: effects of duration dry and light stress in Timmiella crassinervis.

Many terrestrial mosses of arid and semi-arid environments experience excess light during extended periods of desiccation that they are unable to process. Upon rehydration, a moss must process the excess light energy before photoinhibition occurs and reactive oxygen species (ROS) cause cellular damage. This study aims to determine the effect of duration dry and variable light exposure (PAR) on slow-dried, field-hardened shoots of the chaparral moss species Timmiella crassinervis, as well as to evaluate the ideal rehydration light conditions for this species. I propose the following hypotheses: mosses exposed to high light intensities while dry, for longer duration dries, will incur more damage upon rehydration than those exposed to lower light intensities. Additionally, light intensity during rehydration will determine the ability and extent to which a moss can recover from light stress while dry with lower light intensities being more conducive to recovery than higher light intensities. Previously air-dried shoots were kept dry by placing them in desiccation jars at 42% relative humidity. Desiccation jars were then placed in a growth chamber at four different light levels (high, mid, shade, no) and kept under the corresponding light levels for duration dries of 7, 14, 21, and 28 days. After each respective duration dry, four groups of five shoots from each light level were rehydrated and placed at each of the four light levels for the duration of their rehydration. Chlorophyll fluorescence measurements were taken at a range of times post-rehydration (0, 24, 48, 72 h) to assess relative shoot health and recovery from light stress.


1 - University of Nevada, Las Vegas, School of Life Sciences, 4505 Maryland Parkway, Las Vegas, NV, 89134, USA

Keywords:
bryophytes
moss
desiccation tolerance
light stress
duration dry
Timmiella crassinervis .

Presentation Type: Oral Paper
Number: 0004
Abstract ID:628
Candidate for Awards:None


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