Evolution of Salt Tolerance in Two Coexisting Species of Grass

Abstract

ALTHOUGH the tolerance of plants to salt is of great economic importance and has received detailed attention, data for contrasting populations of species that occur naturally in saline and non-saline habitats are limited. Demonstrations of the significance of salt in the distribution of forms of Typha by McMillan¹ and McNaughton² are notable exceptions. We have therefore examined the salt tolerance of populations of Festuca rubra L., which occurs in both the lower and upper regions of salt marshes and in the adjacent non-saline uplands, and of Agrostis stolonifera L. which coexists with Festuca in the upper marsh and upland. Five such populations were collected from each of two geographically separate but otherwise similar sites (Aber, Caernarvonshire and Malltraeth, Anglesey).