Abstract Detail

Ecological Section

Beaton, Laura L. [1], Dudley, Susan A. [2].

The impact of solute leaching on the salt tolerance during germination of a common roadside plant Dipsacus sylvestris (Dipsaceae).

Variation in salt tolerance during germination has been found in Dipsacus sylvestris collected from roadsides and oldfields, with roadside populations displaying a greater salt tolerance that is highly correlated with seed sodium ion (Na⁺) content.  We hypothesized that the salt tolerance during germination was conferred through the deposition of Na⁺ in seeds by the maternal plant.  To determine the role of Na⁺, we leached the soluble components from seeds prior to salt exposure and compared the salt tolerance of leached seeds and unleached seeds.  Seeds from maternal families from the roadside showed higher salt tolerance than those from oldfields.  Leaching the seeds prior to salt exposure had no impact on the salt tolerance of oldfield families but, caused some roadside families to lose salt tolerance.  The results suggest that roadside populations of D. sylvestris possess two distinct salt tolerance strategies, one in which the seed composition confers tolerance to the osmotic stress of high salinity and the other, an inherent ability to tolerate highly saline conditions.  This study high levels of diversity among D. sylvestris populations in the roadside environment, with variation present not only in the ability to tolerate high salinity but, also in the mechanism.   

1 - Washington University, Department of Biology, Rebstock, 1 Brookings Drive, Campus Box 1137, St. Louis, Missouri, 63130, USA
2 - McMaster University, Biology, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada

Keywords:
ion toxicity
local adaptation
maternal environmental effects
osmotic stress
seed composition.

Presentation Type: Oral Paper
Session: 43-4
Location: Salon F - Austin Grand Ballroom/Hilton
Date: Wednesday, August 17th, 2005
Time: 8:45 AM
Abstract ID:25