Representative transmission electron micrographs. (A) Untreated cell before dark cultivation (control) and the cells that had been heat treated and then cultured in the dark for (B) 0, (C) 2, (D) 6, (E) 12, (F) 24, (G) 48 and (H) 72 h, respectively. Bars = 1 μm. Abbreviations: c, chloroplast; m, mitochondrion; n, nucleus; nl, nucleolus; s, starch granule; v, vacuole. Arrows in (B): condensation of chromatin on the inner side of the nuclear membrane. Arrows in (E-G): exudation of organic substances between the cell wall and the cell membrane. Arrow in (H): rupture of cell membrane.