Timing of phosphate application affects arsenic phytoextraction by Pteris vittata L. of different ages

Abstract

The effects of timing in phosphate application on plant growth and arsenic removal by arsenic hyperaccumulator Pteris vittata L. of different ages were evaluated. The hydroponic experiment consisted of three plant ages (A45d, A90d and A180d) and three P feeding regimens (P200þ0, P134þ66 and P66þ134) growing for 45 d in 0.2-strength HoaglandeArnon solution containing 145 mg L 1 As. While all plants received 200 mM P, P was added in two phases: during acclimation and after arsenic exposure. High initial P-supply (P200þ0) favored frond biomass production and plant P uptake, while split-P application (P134þ66 and P66þ134) favored plant root production. Single P addition favored arsenic accumulation in the roots while split-P addition increased frond arsenic accumulation. Young ferns (A45d) in treatment P134þ66 were the most efficient in arsenic removal, reducing arsenic concentration to below 10 mg L 1 in 35 d. The results indicated that the use of young ferns, coupled with feeding of low initial P or split-P application, increased the efficiency of arsenic removal by P. vittata. 2007 Elsevier Ltd. All rights reserved.