Figure 5.

Surface area-based rates of alkalinization of solutions bathing excised root apices of signalgrass (B. decumbens) and ruzigrass (B. ruziziensis) (means ± se of four to six groups of 30 apices each). Plants were cultivated at increasing Al levels as in Figure 2. Excised root apices were incubated for 2 h in 200 μm CaCl₂ (pH 4.2), containing either no Al or {Al³⁺} = 115 μm. A, Incubation of excised root apices without Al. B, Incubation of apices at {Al³⁺} = 115 μm. Asterisks denote statistically significant interspecific differences (P < 0.05).