Abstract Detail

Desiccation tolerance in bryophytes: perspectives from early career scientists

Greenwood, Joshua [1].

Influence of life history phase, genotype, and rate of drying upon desiccation tolerance in Bryum argenteum.

Desert adapted mosses are among the hardiest organisms on earth. However, the full complexity of the methods by which this is achieved and the factors that influence survival have eluded researchers for decades. Over the previous three years our lab has established the presence of an inducible desiccation tolerance (DT) strategy within bryophytes. This more nuanced understanding is in opposition to the previous dominant concept, which described all mosses as either DT or non-DT. With this study I set out to expand upon previous work by uncovering which factors have the greatest influence upon desiccation recovery. In this study DT capacity is explored using the cosmopolitan moss Bryum argenteum. This species makes an ideal study system due to its high capacity for DT, multiple distinct life history stages, worldwide distribution, habitat diversity, and dioecious nature. Interaction as well as single factor effects were examined to determine the relative influence of genotype, sex, life history phase, and rate of drying upon post-desiccation recovery. Results from this study show a surprising number of factors play a role in DT, further illustrating the complex nature of the DT response. Findings indicate that juvenile mosses of B. argenteum require a greater amount of time to prepare for desiccation compared mature adults of the species, and that rate of drying has an effect upon all life history phases. Genotypic variation was greater than expected (predominately at juvenile stages) with some forms displaying a high tolerance level across treatments and some genotypes requiring a slow drying rate to reduce damage. Drying rates applied ranged from direct exposure to an atmosphere of 50% relative humidity (RH) to a maximum 28 hours to reach equilibration at 50% RH, corresponding to nine hours of active metabolism after which the water content of the moss is below 86% RH.

1 - University of Nevada Las Vegas, School of Life Sciences, Las Vegas, NV, 89154-4004, USA

Keywords:
osmotic stress
Fv/Fm
stress tolerance
poikilohydry.

Presentation Type: Symposium Presentation
Session: SY11
Location: Salon 8/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 2:45 PM
Number: SY11004
Abstract ID:1248
Candidate for Awards:None