Fig. 3

Net photosynthetic rate of remaining leaves (AREM) of Amorpha fruticosa (a, b) and Robinia pseudoacacia (c, d) under different defoliation treatments. The values shown are mean ± SE (n = 4). The asterisk represents the significant difference (p < 0.05) between the control group and the defoliation group; CK, no defoliation; TD, defoliation of the top down 50% of the crown; BU, defoliation of the bottom up 50% of the crown. CK in a and c, upper leaves in the crown were measured, whereas b and d concerned lower leaves