Fig. 7
Comparison of sugars contents and activities of Suc hydrolyzing enzymes in Citrus and its relatives under cold stress. A-D Dynamic changes of Suc (A), Glc (B), Frc (C) and total sugar contents (D) during cold stress. E-H Dynamic changes in the activities of A/NINV (E), VINV (F), CWINV (G) and SuSy (H) enzymes during cold stress. I-J Dynamic changes of HXK activity (I) and G-6-P content (J) during low temperature. K Schematic representation displays the Suc catabolism pathways in response to cold stress. Ptr, P. trifoliata; Ci, C. ichangensis; Cs, C. sinensis; Cg, C. grandis; Cl, C. limon and Fj, Fortunella japonica seedlings were exposed to 4 °C for three days. The significant difference was analyzed using one-way ANOVA and displayed as (*P < 0.05, **P < 0.01, ***P < 0.001) and indicated by different colored arrow. Error bars refer to ± SE (n = 3)