Objectives The accumulation ability of phosphorus (P) in Pilea sinofasciata, a P-enrichment plant, was investigated to provide a theoretical basis for extracting excess P in soil.
Methods The seedlings of P. sinofasciata were cultured in the pots in a greenhouse under natural light at Sichuan Agricultural University, Sichuan Province, China in 2017. The responsive effects of high phosphorus treatments including 400, 600, 800 mg/kg were analyzed by profiling the high-P tolerance and accumulation capability in P. sinofasciata under application of optimum nitrogen (N 140 mg/kg). The used soil was a typical calcareous alluvial soil containing various concentrations of phosphorus (P 0, 400, 600, 800 mg/kg) and cultured for 8 weeks, and total of 140 mg/kg of nitrogen was applied. After continuously culturing for another 9 weeks, the plants were harvested. Both the biomass and the phosphorus accumulation in plant were determined, and the available-P concentration in soil was analyzed.
Results 1) The biomass of shoot and root in both ecotypes significantly increased when supply of phosphorus was P 600 mg/kg, and then decreased under supply of P 800 mg/kg. Biomass of shoot and root in mining ecotype (ME) were increased 2.37 and 3.69 folds compared with the control under supply of P 600 mg/kg, respectively. And biomass of shoot and root in non-mining ecotype (NME) were increased 4.63 and 7.36 folds compared with the control under supply of P 600 mg/kg, respectively. The maximum shoot biomass in both the ME and NME were observed under supply of P 600 mg/kg, and were 28.6 g per plant and 31.9 g per plant, respectively. The biomass of shoot and root in the ME were significantly higher than those in the NME under supply of P 0 or 400 mg/kg. However, no difference was found under supply of P 600 or 800 mg/kg. 2)The phosphorus concentration in the shoot of both ecotypes and in the root of the ME significantly increased when supply of phosphorus was P 600 mg/kg, and decreased under supply of P 800 mg/kg. However, the phosphorus concentration in the root of the NME was increased when supply of phosphorus was increased to P 800 mg/kg. The phosphorus concentration in the shoot of the ME was significantly higher than that of the NME, but the phosphorus concentration in the root of the ME was lower than that of the NME. 3) The high phosphorus treatment significantly improved phosphorus accumulation in the shoot and root of two ecotypes. The maximum phosphorus accumulation in the shoot of the ME and NME occurred at supply levels of P 600 mg/kg, and were 195 mg per plant and 182 mg per plant, respectively. The phosphorus accumulation in the shoot of the ME was significantly higher than that of the NME under supply of P 0 or 400 mg/kg. However, no difference was found under supply of P 600 or 800 mg/kg. 4) Under the condition of phosphorus treatment, the bioaccumulation coefficient in both ecotypes was more than 1, while its translocation rate was higher than 80%. Moreover, the extraction rate and the removed phosphorus in the ME were higher than those in the NME under supply of P 0 or 400 mg/kg. However, no difference was found under supply of P 600 or 800 mg/kg.
Conclusions Under condition of optimum N dosage, P. sinofasciata showed great P accumulation potentials under supply of P 600 mg/kg. The phosphorus accumulation capacity of the ME was higher than the NME under supply of P 0 or 400 mg/kg, however, no difference was found under supply of P 600 or 800 mg/kg.
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