Increased Uptake of Bromide and Chloride by Plants Infected With Vesicular‐arbuscular Mycorrhizas

SUMMARY Concentrations of bromide in shoot tissue of field‐grown spring wheat and winter barley on sites both with and without methyl bromide fumigation were significantly higher in plants given mycorrhizal inoculum. In a pot experiment with spring wheat under controlled conditions, mycorrhizal inoculation increased bromide and chloride concentrations in plant tissue, but effects on iodide concentrations were small and inconsistent. A specific ability of mycorrhizal plants for increased uptake of chloride and bromide through mycorrhizal hyphae seems unlikely because both ions are highly mobile in the soil and readily absorbed by roots. An analysis of the cation–anion balance of shoot tissue from a field trial of spring wheat showed that mycorrhizal inoculation increased concentrations of inorganic anions, whilst cation concentrations were little altered. A possible explanation of the increased uptake of halides by mycorrhizal plants may be that the production of organic anions is restricted by the drain of carbon from the host by mycorrhizal fungi.