Fig. 3

Effects of salt stress on the photosynthetic system of P. macrophyllus. A Ultrastructure of P. macrophyllus chloroplasts with or without (CK) salt stress treatment (300 mM NaCl). Scale (1 μm, 0.5 μm and 0.2 μm). SS, short-term salt treatment. LS, long-term salt treatment. T, OG, chl and SG indicates the thylakoid lamellae, osmiophilic globule, chloroplasts and starch grain, respectively. B The contents of chlorophyll a and C chlorophyll b in leaves of P. macrophyllus under SS and LS salt stress treatment. D The maximum quantum yield (Fv/Fm) in leaves of P. macrophyllus under SS and LS salt stress treatment. Data shown are the average mean ± SE of three replicates (n = 3). Different letters above the bars indicates statistical significance at the P < 0.05 level among different concentrations of NaCl treatments according to Tukey’s test