Nitrogen fixation in relation toHudsonia tomentosa: a pioneer species in sand dunes, northeastern Alberta

摘要

Blue-green algae, including species ofOscillatoria,Lyngbya,Microcystis, and Nostocaceae were isolated from green sand associated withHudsonia tomentosa. Green sands were consistently found in the buried phyllosphere and rhizosphere ofHudsoniaand on the surface to varying depths underHudsoniaplants. Organisms in these sands fixed nitrogen at maximum rates of 1ensp;nmolensp;C2H4∙gensp;soilminus;1∙hminus;1. Seasonal variation in rates was largely explained by optima of 30 soil water content and 28 to 33 deg;C soil temperature. Green sands were not associated with any other vascular plant at the study sites. The results suggest a preference of free-living blue-green algae forHudsoniawhich may relate to the ability of this dwarf shrub to colonize nutrient-poor sand sites, such as blowouts and sand dunes in thePinus banksianandash; lichen woodlands of northeastern Albe