Germination and Seedling Growth of Tall Wheat-Grass and Basin Wildrye in Relation to Boron

Abstract

Seedling establishment on many saline, arid rangeland soils in the Great Basin may be limited not only by low soil osmotic and matric potentials, but also by high boron concentrations. Germinationa and seedling growth of tall wheatgrass [Agropyron elongatum (Host) Beau. 'Jose'] and basin wildrye (Elymus cincereus Scribn. and Merr. 'Magnar') were measured in relation to increasing boron concentrations in laboratory and greenhouse experiments. Rate and total germination of both species were unaffected by boron concentrations up to 200 ppm, while radicle length was unaffected at less than 100 ppm. Growth of both species was much more sensitive to boron than was germination. Root growth of both species was more sensitive to boron than shoot growth. Shoot growth of Jose tall wheatgrass was less sensitive to boron than that of Magnar basin wildrye. Reduction in root and shoot yield of 50% occurred at soil saturation extract concentrations of 30 and 66 ppm of boron, respectively, for Jose tall wheatgrass, and 22 and 37 ppm of boron, respectively, for Magnar basin wildrye. Boron concentrations ranging up to 97 ppm in the saturation extract of a typical Great Basin saline soil in central Nevada would probably affect seedling growth and survival, but not emergence of these species. The fact that Jose tall wheatgrass has greater absolute root growth and boron tolerance than does Magnar basin wildrye may account, in part, for its greater seedling survival on a saline soil in central Nevada.