Lithium toxicity in plants

Abstract

The toxicity of Li to 3 plant species was studied to determine if there were interactions with other elements and if a chelating agent modified Li toxicity. Bush beans (Phaseolus vulgaris L. cv. Improved Tendergreen), grown in solution culture, were sensitive to 0.5 .times. 10-3M Li which resulted in 10 .mu.g/g in leaves, 48 in stems and 24 in roots. Higher concentrations of Li produced marked reductions in plant yield accompanied by increased Li concentrations in leaf, stem and root tissues. For most treatment, root concentrations of Li were lower than those in shoots, but those in stems were higher than in leaves. Higher levels of Li decreased Zn in leaves, increased Ca in stems, and generally increased Fe and Mn in all plant tissues. EDTA resulted in slightly increased Li levels in leaves, stems and roots. Bush bean plants were injured slightly with 25 .mu.g Li/g of Yolo loam soil applied as LiCl; 50 .mu.g Li/g soil caused more severe injury. Leaf concentrations of about 200 .mu.g Li/g resulted in significant yield reduction and around 600 .mu.g/g of leaves resulted in severe toxicity. There were some interactions of Li with other elements which resulted in an increase in leaf and stem tissues. Barley plants (Hordeum vulgare L. cv. Atlas 57) were severely stunted when grown with 500 and 1000 .mu.g Li/g soil as Li oxalate. Increasing the soil pH even further with lime and decreasing it with S had no influence on the toxicity. Shoot concentrations of Li ranged from 800 to over 2000 in the various treatments, resulting in severe disruption of the Ca and K balance. Leaf concentrations of Li were higher than those for stems in cotton (Gossypium hirsutum L. cv. Acala 442). Cotton was tolerant of a leaf concentration of 587 .mu.g Li/g. High levels of Li increased concentrations of several elements in cotton leaves and stems. Cotton leaves accumulated more Li than bush beans.