Effects Of Phytic Acid On Arsenate Tolerance And The Root Biased Growth In Arabidopsis Thaliana

With the development of modern industry and agriculture, environmental pollution is increasing. Arsenic (As) is a metalloid that is highly toxic to microbes, plants, animals and humans. Arabidopsis, as a model plant, is suitable for analyzing arsenic metabolism in nonhyperaccumulator. But till now limitted is known about the molecular mechanisum of Arsenic absorbing and transferring in Arabidopsis. Phytic acid is a phosphorus reservoir in plants. With treatment of P and phytic acid, the experiment mainly focused on the plant growth, As accumulation and distribution in Arabidopsis in response to As treatment. We also explored phytic acid’s potential for repair injury caused by different valence state of As pollution in Arabidopsis thaliana. The test found that phytic acid can promote bias growth of Arabidopsis roots. The main results are as follows:(1) Phosphorus at an appropriate content alleviate the toxic effects of arsenic on Arabidopsis by inhibiting the absorption of arsenic. Treat Arabidopsis with different concentrations of P upon As treament, we found that P can alleviate arsenic poisoning considerably. Moreover, arsenic uptake increase under the P-free conditions and decrease under P treament. This result is quite similar to the previous results.(2)The toxic effects of arsenic on Arabidopsis can be alleviated by phytic acid, and the process is largely dependent on the valence state of the arsenic. Treat Arabidopsis both in wild type and mutant with different concentrations of phytic acid and As, we found that the poisoning caused by arsenate treatment was significantly weakened or even disappered by adding phytic acid. Determination of As content in different parts of Arabidopsis shows that root is the main part absorbing As. Different concentrations of phytic acid treatment can significantly improve the resistance of Arabidopsis to As V, but can not alleviate the toxicity of As III on Arabidopsis thaliana.(3) The metabolism of phytic acid affect the biased growth of Arabidopsis roots. Ttreat Arabidopsis both in wild type and mutant with different concentrations of phytic acid, we found that phytic acid can promote a bias root growth in Arabidopsis, the deflection in the same direction. While this phenomenon disappeared under high concentrations of P or in a phytase gene deletion mutant atminpp.We believe that high concentrations of P suppress phytic acid metabolism and atminpp phytase deletion mutants impair the degradation of phytic acid, which can be further concluded that it is phosphoinositide come from phytic acid metabolism that caused the Arabidopsis root biased growth.