Fig. 2. Effect of P treatment on root volume during the experiment in hydroponics. P0 = 0.0 mol L^–1, P1 = 0.073 10^–3 mol L^–1, and P2 = 1.65 10^–3 mol L^–1. Each point is the mean of three replications (bars = ± standard error). For a given date of measurement, means followed by different letters are significantly different at P < 0.05 according to the Student Newman Keul's range test.