Effects of selenium on germination and radicle elongation of selected agronomic species

Abstract Certified seeds of cabbage ( Brassica oleracea var. capitata L.), lettuce ( Lactuca sativa L.), radish ( Raphanus sativus var. radicula Perzoon.), two varieties of sorgrass ( Sorghum vulgare sudanense Hitchc. var. Dub-L-Graze and var. Sugar-Graze), turnip ( Brassica rapa L.), and wheat ( Triticum aestivum L. var. Caldwell) were treated with fresh, pH-adjusted solutions of 0, 1, 2, 4, 8, 16, and 32 mg Se/l in either the selenate or selenite form for 2–4 days. Seed germination and seedling radicle length were measured to determine plant sensitivity to Se. Germination was unaffected by Se treatment. The effect of Se on radicle length varied with plant species, Se form, and Se concentration. Selenite treatment generally caused the greater decrease in radicle length. Plant sensitivity to selenate varied as follows: turnip > Sugar-Graze sorgrass = lettuce = cabbage > Dub-L-Graze sorgrass = wheat > radish. For selenite, the sensitivity ranking was: turnip = cabbage > Sugar-Graze sorgrass > radish = lettuce = Dub-L-Graze sorgrass > wheat. Sensitivity to Se varied not only among plant species, but also between the two sorgrass varieties.