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

摘要

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 (A_(45d), A_(90d) and A_(180d)) and three P feeding regimens (P_(200+0), P_(134+66) and P_(66+134)) growing for 45 d in 0.2-strength Hoagland-Amon solution containing 145 μg L~(-1) As. While all plants received 200 μM P, P was added in two phases: during acclimation and after arsenic exposure. High initial P-supply (P_(200+0)) favored frond biomass production and plant P uptake, while split-P application (P_(134+66) and P_(66+134)) favored plant root production. Single P addition favored arsenic accumulation in the roots while split-P addition increased frond arsenic accumulation. Young ferns (A_(45d)) in treatment P_(134+66) were the most efficient in arsenic removal, reducing arsenic concentration to below 10 μg 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.