A polymorphism for phosphate uptake/arsenate tolerance in Holcus lanatus L.: is there a correlation with edaphic or environmental factors?

Arsenate tolerance in Holcus lanatus L. is achieved by suppression of the high affinity phosphate uptake system. Tolerant plants are found at high frequency on noncontaminated soils. The selective agents acting to maintain this polymorphism are not understood. Work on the Park Grass Experiment and a nationwide survey revealed no significant correlation between the frequency of tolerant individuals and environmental or edaphic characteristics of the site. The results are interpreted in light of the low availability of phosphate in soil solution.