Abstract Detail

Bryological and Lichenological Section/ABLS

Slate, Mandy [1], Callaway, Ragan [2].

Moss Rehydration Leachate.

When mosses dry out, their cell membranes shrink, twist, and contort before the plant becomes more or less inactive as they wait for water.  During this drying process, the plant synthesizes rehydration proteins which are stored until the onset of rehydration.  These proteins are later needed to repair the dehydration damaged cellular membranes that leak fixed carbon, secondary metabolites, and mineral ions immediately upon rehydration.  Desiccation tolerant bryophytes quickly bridge this gap of time between the onset of rehydration and completed cellular membrane repair and return to normal levels of photosynthetic functioning within a few minutes.  Conversely, desiccation-intolerant species show signs of cellular degradation if dried too rapidly, vary in how much leachate they lose during rehydration and take much longer to repair their cellular membranes and reach full photosynthetic recovery.  Additionally, there is a great deal of variation in inter-cellular carbohydrate composition among bryophyte species making it likely that moss species will differ not only in how they release and retain various intra-cellular compounds but also in what compounds are actually released. 
Early research focused on the physiological mechanisms behind this process (e.g. rehydration proteins and specialized vesicles) and examined moss rehydration and rehydration leachate within the confines of highly controlled conditions in containers where over time the mosses reabsorbed their leaked nutrients.  Few studies have measured these rehydrating pulses in nature and no studies have explicitly compared the release of resources between hydrated and dehydrated mosses. Additionally, in moss species that exhibit upright growth (acrocarps), leachate will first pass through a water starved moss canopy which can hold 5-10 times its dry weight in water and thus act as a strong absorbent buffer.  In contrast, moss species that grow very close to the ground (pleurocarps) do not form cushions and are less likely to be as absorbent.  I have subjected six species representative of both growth forms to varied lengths and levels of hydration, dehydration, and rehydration to compare how rehydration leachates differ in composition between species and among these treatments.

1 - University Of Montana, OBE, 2133 A Dearborn Av, Missoula, MT, 59803, USA
2 - University Of Montana, Division Of Biological Sciences, Missoula, MT, 59812, USA

Keywords:
bryophytes
rehydration.

Presentation Type: Oral Paper:Papers for Sections
Session: 2
Location: Firs North/Boise Centre
Date: Monday, July 28th, 2014
Time: 9:00 AM
Number: 2005
Abstract ID:404
Candidate for Awards:A. J. Sharp Award