3.3. Plant growth and nutrient uptake in tomato plants
As PG6 was most effective in solubilizing P from phytate at 0.89 mg L−1 P (Table 1), spent media from PG6 was added to 0.2-strength HNS containing low P at 1 mg L−1, with or without 0.2 g of phytate to grow tomato plants for 7 d. The addition of spent media from PG6 and control PC enhanced tomato growth than the control, with PG 6 being more effective than PC. The shoot biomass increased by 65% to 0.56 g per plant with PG6 addition compared to the control and 44% compared to control PC (Fig. 2A). We hypothesized that the increase in plant biomass was probably associated with the increased P uptake by tomato, which was supported by P data in tomato plant biomass (Fig. 2B). The P concentrations in tomato roots and shoots in PG6 treatment was 1.8–2.2 fold higher (8.63–9.20 mg g−1) than that in the control PC (4.1–7.6 mg g−1).