Figure 1From: Pb-induced cellular defense system in the root meristematic cells of Allium sativum LTEM micrographs showing toxic effects of Pb on ultrastructure of the root meristematic cells of A. sativum. a: Control cells showing well-developed root tip cells. b-f: The ultrastructural changes of root meristematic cells exposed to 10-4 M Pb for 1-2 h. b: Obvious increase in dictysome vesicles and formation of increasing numbers of vesicles near the cell wall at exposure for 1 h. c: Large amount of ER near the cell wall and some with distinct dilation of flattened cisterna after Pb treatment for 2 h. d: Flattened cisternae broken up into small closed vesicles (arrow). e: The nuclear envelope swelling in the root meristem after treatment for 4 h. f: Cytoplasm membrane invaginations (arrow) and active phagocytosis during the 4-h treatment. C = cytoplasm, CM = cytoplasm membrane, CW = cell wall, D = dictyosome, ER = endoplasmic reticulum, EDG = electron-dense granules, M = mitochondria, N = nucleus, NE = nuclear envelope, V = vacuole, Ve = vesicle. Bar = 0.25 μm.Back to article page