Effects of Selenium Valence States and Concentration on Germination and Root Growth of Six Crop Species

Effects of selenium on seeds germination and root growth were studied by culture experiment with 6 species under different Se valence states(Se6+ and Se4+) and concentrations(0～100 mgSe·L-1).The results showed that the significant inhibition effect can be found at high Se concentration,germination resistance to Se for the crop species sequence was:barley and broccoliwheatradish and medicparsley.Results of root and shoot length showed that the seed growth of broccoli and wheat was improved below 1 mgSe·L-1 while parsley was inhibited.The inhibition effects on root growth were found when Se concentration was higher than 2 mgSe·L-1 for broccoli,medic and parsley,and higher than 4 mgSe·L-1 for wheat,barley and radish.The inhibiting Se concentrations for shoot growth were found higher than that for root growth,at the same time.Selenate showed more obvious improvement effect on broccoli growth than selenite at low concentration.Wheat and medic had higher resistance to Se with selenate than with selenite at high Se concentration,while other species did not show significant difference.The species sequence of root growth resistance to Se was:wheat and barley(gramineous) was the best,followed by broccoli and radish(cruciferous),and then was medic(leguminous),parsley(umbelliferous) was the worst.