A greenhouse study of selenium uptake by yellow sweet clover and fourwing saltbush

摘要

Yellow sweet clover and fourwing saltbush seeds were grown in pots containing a seleniferous Wyoming pasture soil. Soil treatments consisted of steaming (65-80° C, 14h) adding root fragments as a vesicular-arbuscular mycorrhizal (VAM) supplement, and adding selenium as selenite and selenate. Plant growth parameters (germination, survival, and plant height) were measured. Plants were harvested approximately 130 days after planting, and plant selenium, phosphate-extractable soil selenium, and VAM root colonization were determined.;Steaming the soil affected germination and height of fourwing saltbush and dramatically decreased plant selenium concentrations for both plants. No VAM colonization was found in fourwing saltbush roots. Yellow sweet clover roots were colonized, but the extent of colonization had no effect on plant selenium uptake. Root supplements had no effect on germination, height, or selenium uptake in either plant, but possibly influenced fourwing saltbush survival in selenate-amended soils. Adding selenium (3 mg Se kg-1) to the soil had no effect on germination of yellow sweet clover but provided an advantage to fourwing saltbush plants grown in selenite-amended soil. Amending the soil with selenate did not affect germination, but was lethal to most seedlings and prevented growth of survivors of both plant types. Selenite amendments did not affect yellow sweet clover plant height or VAM colonization, but did adversely affect fourwing saltbush plant height. Phosphate-extractable selenium values were similar for selenite- and selenate-amended soils.