Fig. 3. Photo-orientation movement of chloroplasts in the aquatic angiosperm Vallisneria gigantea epidermal cells. Cross-sections of leaf epidermal cells, in which chloroplasts accumulated along the outer periclinal wall (OPW) under dim light (A) or along the anticlinal walls (AW) under strong light (B). V, central vacuole. Scale bar: 5 µm.