Fig. 2

The stomatal morphology and traits in leaves of Z. xanthoxylum under control and heat treatments for 10 days (6 h/d). The stomatal distribution (a-c) and size (d-f) of leaves at 25 °C (a, d), 40 °C (b, e) and 45 °C (c, f), respectively. Scale bars (a-c) = 50 μm, Scale bars (d-f) = 10 μm. The stomatal length (g), width (h), area (i), aperture (j) and density (k) of leaves were measured. The time of the beginning of the light phase of the day is 6:00 o’clock. Values in (a-i) are mean ± SE (n = 15). Asterisks indicate significant differences in comparison with control (25 °C) (* P < 0.05, ** P < 0.01, *** P < 0.001, Student’s t-test)