Enhanced P accumulation characteristics and P removal potentials of Pilea sinofasciata grown under P enriched soils supplied with nitrogen

Phytoextraction is an attractive method to extract excess soil P. However, most of the potential P accumulators have relatively low P removal potential when used for extracting excess soil P. An important question then is how can we improve the P uptake capability of P accumulators? This study was conducted to investigate the effects of different nitrogen (N) treatments (0-350 mg N kg−1) on growth, P accumulation characteristics, and P removal potentials of P. sinofasciata. A mining ecotype (ME) and a non-mining ecotype (NME) were grown for 9 weeks in P enriched soils affected by different N treatments. The pot survey revealed that two ecotypes of P. sinofasciata showed significant increases in shoot biomass and P accumulation with ascending N supplied up to a level of 140 mg N kg−1, beyond which a notable decrease was found. The ME demonstrated greater shoot biomass and P accumulation than the NME. The P extraction ratio in shoot of the ME reached 15.92% under 140 mg N kg−1, and increased by 30.08% compared with that of NME. Shoot P removal of the ME reached 29.58 mg kg−1 under 140 mg N kg−1 which was higher than the NME. The ME and NME both showed high levels of P removal from soil, maximum potential yield, and P removal potential after the addition of N. In conclusion, both ecotypes of P. sinofasciata show high P accumulation and P removal from N impacted soils, and thus P. sinofasciata is a potential and worthy candidate for phytoextraction.