10.1021/acs.est.7b05836.s001 Nimisha Edayilam Nimisha Edayilam Dawn Montgomery Dawn Montgomery Brennan Ferguson Brennan Ferguson Amith S. Maroli Amith S. Maroli Nicole Martinez Nicole Martinez Brian A. Powell Brian A. Powell Nishanth Tharayil Nishanth Tharayil Phosphorus Stress-Induced Changes in Plant Root Exudation Could Potentially Facilitate Uranium Mobilization from Stable Mineral Forms American Chemical Society 2018 batch dissolution experiments root exudate matrix FePO 4 acid Plant Root Exudation soil mineral nutrients PO 4 Phosphorus Stress-Induced Changes root exudates KH 2 PO 4 uranyl phosphate mineral Chernikovite Stable Mineral Forms Apparent deficiency Facilitate Uranium Mobilization 2018-05-03 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Phosphorus_Stress-Induced_Changes_in_Plant_Root_Exudation_Could_Potentially_Facilitate_Uranium_Mobilization_from_Stable_Mineral_Forms/6737222 Apparent deficiency of soil mineral nutrients often triggers specific physio-morphological changes in plants, and some of these changes could also inadvertently increase the ability of plants to mobilize radionuclides from stable mineral forms. This work, through a series of sand-culture, hydroponics, and batch-equilibration experiments, investigated the differential ability of root exudates of <i>Andropogon virginicus</i> grown under conditions with variable phosphorus (P) availability (KH<sub>2</sub>PO<sub>4</sub>, FePO<sub>4</sub>, Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, and no P) to solubilize uranium (U) from the uranyl phosphate mineral Chernikovite. The mineral form of P, and hence the bioavailability of P, affected the overall composition of the root exudates. The lower bioavailable forms of P (FePO<sub>4</sub> and Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>), but not the complete absence of P, resulted in a higher abundance of root metabolites with chelating capacity at 72 hrs after treatment application. In treatments with lower P-bioavailability, the physiological amino acid concentration inside of the roots increased, whereas the concentration of organic acids in the roots decreased due to the active exudation. In batch dissolution experiments, the organic acids, but not amino acids, increase the dissolution U from Chernikovite. The root exudate matrix of plants exposed to low available forms of P induced a >60% increase in U dissolution from Chernikovite due to 5–16 times greater abundance of organic acids in these treatments. However, this was ca. 70% of the theoretical dissolution achievable by this exudate matrix. These results highlight the potential of using active management of soil P as an effective tool to alter the plant-mediated mobilization of U in contaminated soil.