No evidence for competition between arsenate and phosphate for uptake from soil by medic or barley

作者：Christophersen H M^*; Smith S E; Pope S; Smith F A

来源：Environment International, 2009, 35(3): 485-490.

DOI：10.1016/j.envint.2008.07.011

• Arsenic
• Arsenate (As(V)) uptake
• Phosphorus
• Toxicity

We investigated the effects of phosphorus (P) supply on the uptake and toxicity of arsenate (As(V)) in two plant species (Medicago truncatula and Hordeum vulgare) grown in soil/sand mixes. Our initial hypothesis was that competition between phosphate (Pi) and As(V) for uptake would be observed, and that this would be the basis for the 'protective' effect of P with respect to As toxicity, as shown in solution culture. Addition of P to the soil/sand mixes did not have major effects on water extractable As, or vice versa. We observed that toxic effects of As(V) on plant growth were ameliorated by increased P in both plant species. However, we found no evidence that increased P supply reduced specific uptake of As(V) on a molar basis. so that competition with Pi could not be the basis for the effect. A more complex mechanism of protection is indicated which might relate to different Pi transport systems being expressed at different P levels.

• 出版日期2009-4