Figure 5.

Electron micrographs of root tip cells of 15 day-hydroponically grown seedlings of Brassica napus cv. ZS 758. (a-b) TEM micrographs of root tip cells of ZS 758 at 400 μM Pb alone at low and high magnifications, respectively, show undeveloped nucleus (N) with broken nuclear membrane (NM), undeveloped mitochondria (MC), disappearance of endoplasmic reticulum (ER), and cracked cell wall (CW). Moreover, Pb accumulation increased in the form of electron dense granules along the cell wall and vacuole (V). (c-d) TEM micrographs of root tip cells of ZS 758 at 25 mg L⁻¹ 5-aminolevulinic acid (ALA) under 400 μM Pb concentration at low and high magnifications, respectively, show a clear cell with big nucleus (N), number of developed mitochondria (MC), golgi bodies (GB), and cell wall (CW).