**2. Results**

### *2.1. Biomass Production at the Flowering Stage*

In Experiment 1 we compared the LP-F10 progeny with the cultivar Enrei (Figures 1–3 and Table 1). The whole plant weight of both the LP-F10 line and Enrei was significantly affected by the higher P application at the flowering stage (Figure 1). The whole plant weight in both the LP line and normal-phytate cultivar in the P150 treatment was 1.5 to 1.6 times higher than that in the P50 treatment, respectively. However, there was no difference in the whole plant weight between the LP line and normal-phytate cv. Enrei within the same P treatment.

**Figure 1.** Effect of phosphorus fertilization on whole plant dry weight of the LP-F10 progeny and the normal-phytate cv. Enrei (Experiment 1). The same letter indicates no significant difference (*p* ≤ 0.05).

**Figure 2.** Effect of phosphorus fertilization on seed yield in LP-F10 and the normal-phytate cv. Enrei in Experiment 1. The same letter indicates no significant difference (*p* ≤ 0.05).

**Figure 3.** Effect of phosphorus fertilization on seed total P, phytate P and inorganic P concentrations in LP lines and normal-phytate soybean cultivars of soybean in Experiment 1 (**A**) and Experiment 2 (**B**). The same letter indicates no significant difference (*p* ≤ 0.05).

### *2.2. Photosynthesis and Dinitrogen Fixation Activity at the Flowering Stage*

In Experiment 1 the photosynthetic rate and dinitrogen fixation activity in LP-F10 and cv. Enrei were 1.3 and 1.5 times higher (respectively) in the P150 treatment than in the P50 treatment, but there was no substantial di fferences between LP-F10 and Enrei within a given P treatment (Table 1). The nodule number was higher in the higher P application level for both LP-F10 and Enrei however the nodule number of LP-F10 was higher than that of Enrei when grown under the P50 treatment. The specific nodule activity in both LP-F10 and Enrei, obtained by dividing the nitrogen fixation rate by the root nodule weight, was greater in the P50 treatment than in the P150 treatment. No significant di fferences were observed in specific nodule activity of LP-F10 as compared with Enrei within a given P treatment.


**Table 1.** Effect of phosphorus fertilization on photosynthesis and nitrogen fixation in LP-F10 and the normal-phytate cv. Enrei (Experiment 1). The same letter indicates no significant di fference (*p* ≤ 0.05).
