Selenium addition affects early seedling growth of Medicago polymorpha and Trifolium subterraneum, but not seed germination: a preliminary study

Abstract

Little information regarding the effects of selenium addition on germination and early growth of annual leguminous forage crops exists. This study therefore evaluates the effects of selenium addition on the germination and early seedling growth of two annual forage legume species, Medicago polymorpha and Trifolium subterraneum. Seeds were germinated in 120 mm glass petri dishes on a layer of soil. Selenium was applied to the soil as a once-off treatment of sodium selenate dissolved in deionised water at concentrations of 0.25, 0.5, 1.0, 2.0 and 4.0 mg L⁻¹, respectively. The results from the trial indicated that selenium addition had no impact on seed germination, germination rate or germination uniformity. However, early seedling growth was affected, with T. subterraneum displaying negative effects and M. polymorpha showing potentially positive effects on early biomass production. Further research is needed to determine the uptake and allocation of selenium by these forage species as well as a wider range of commercially available leguminous forage species that are commonly used in areas where deficiencies occur.