FIGURE 6.

Light intensity dependence of the photosynthetic electron flow through PSI (ETRI) and PSII (ETRII), and P700⁺ reduction curve in leaves of Al stressed alfalfa seedlings with or without apical buds. Five treatments in the seedlings with apical buds are as Figure 1, and seedlings without apical buds are grown in 1.5 mM Ca(NO3)₂ medium (pH 4.5) and treated with or without spraying IAA (pH4.5-IAA, pH4.5+IAA), 100 μM AlCl₃ with or without spraying IAA (pH4.5+Al-IAA, pH4.5+Al+IAA), and 100 μM AlCl₃ and 50 μM MgCl₂ with or without spraying IAA (pH4.5+Al+Mg-IAA, pH4.5+Al+Mg+IAA). The ETRI (A), ETRII (B), and P700⁺ reduction curve (C) were estimated from seedlings with apical buds, and ETRI (D), ETRII (E), and P700⁺ reduction curve (F) were estimated from seedlings without apical buds at the third day after the initiation of treatments.