Mycorrhizal Development and Plant Growth in Inoculated and Non-Inoculated Plots of California Native Grasses and Shrubs

Abstract

Roots of California brome (Bromus carinatus Hook and Arn. [Poaceae]) and tufted hairgrass (Deschampsia caespitosa (L.) Beauv. [Poaceae]) were more rapidly colonized by arbuscular mycorrhizal fungi (AMF) when grown in plots containing commercial or naturally occurring AMF inoculum, but after 68 wk plants growing in non-inoculated plots had similar colonization and biomass production. Both species would serve as satisfactory carriers of AMF to restoration sites, but Deschampsia supported a higher concentration of spores. Indeed, both species of grass were effective in supplying AMF to Arroyo willow (Salix lasiolepis Benth. [Salicaceae]), but subsequent biomass accumulation of the willow was not associated with either inoculation or root colonization. We conclude that inoculation with AMF is unnecessary except in sites where early colonization is essential.