Vesicular-arbuscular mycorrhiza: Influence on plant uptake of cesium and cobalt

A study was made to determine if infection with vesicular-arbuscular mycorrhizal (VAM) fungi would increase the uptake of ¹³⁷Cs and ⁶⁰Co by Yellow sweetclover [Melilolus officinalis (L.) Lam] and Sudan grass [Sorghum sudanense (Piper) Stapf.]. Plants were inoculated by germinating and growing plants in small volumes of soil containing one of three inoculum sources. Control plants were grown in steam-sterilized inoculum to which sieved (38 μm) inoculum washings had been added. Infected and control plants, with the accompanying soil volume, were subsequently transplanted into pots containing autoclaved field soil which 7 yr previously had been contaminated with ¹³⁷Cs and ⁶⁰Co. The clover was harvested at 65 and 93 days; Cs content was 2.0 and 1.7 times that of the control respectively, on these dates, while Co was not significantly different. The grass was harvested at 85 and 119 days; Cs content was greater in the treated than the control grass, but not significantly; however, Co content was increased 2.5 times that of the control at the first harvest data, but was not significant at the second.