Figure 3
Cell structures of SlSLD-silenced tomato leaves during the period of exposure to chilling stress (4 °C).
Ultrastructural alteration of the chloroplast after exposure to chilling stress. The chloroplasts morphology in mesophyll cell in CK plant (A1, A3, A5) and SlSLD-silenced plant (A2, A4, A6). The normal chloroplasts were observed in CK plant (A1, A3, A5). Although the chloroplasts seem normal under low magnification (A2), swelling of thylakoids was observed (A4, A6 arrows). The chloroplasts morphology in mesophyll cell in CK plant (B1, B3, B5) and SlSLD-silenced plant (B2, B4, B6) was observed after chilling treatment for 6 hours. The grana stacks were clearly in CK plant mesophyll cells (B1). The grana stacks were not observed or in regular morphology in SlSLD-silenced plant mesophyll cells (B2). The chilling damage of chloroplast was observed in CK plant (B3), however, the grana stacks maintained tight oppression (B5). The grana stacks were disappeared in chloroplast (B4). The grana stacks did not maintain tight oppression (B6). Swelling of stromal thylakoids (arrow) and grana thylakoids (double arrows) were observed. The chloroplasts morphology in mesophyll cell in CK plant (C1, C3, C5) and SlSLD-silenced plant (C2, C4, C6) was observed after chilling treatment for 24 hours. The chloroplast was still integrate in CK plant mesophyll cell (C1). The chloroplast was severely destroyed in SlSLD-silenced plant mesophyll cell (C2). The detailed morphology of chloroplast in CK plant (C3). The detailed morphology of disrupted chloroplast in SlSLD-silenced plant (C4). The mitochondrion was accumulated in CK plant epidermal cell (C5). The accumulation of mitochondrion was not observed in SlSLD-silenced plant epidermal cell (C6). CK, tomato leaves injected with TRV vector. SlSLD: TRV, SlSLD-silenced tomato leaves.
