Cd²⁺ subcellular distribution in different cellular compartments of wheat roots.

Abstract

<p>Comparison of immunoelectronic microscope images of Cd^<b>2+</b> distribution in the cell walls of the cortex (A, B), outer tangential wall (C, D) and inner tangential wall (E, F) of endodermal cells, the cell membrane of xylem cells (G and H), plasmodesmata (PD) of phloem cells (I and J), and curdled macromolecular substances in the vacuole (K and L) of root vascular cells of wheat roots from a Cd^<b>2+</b>-negative plant (A, C, E, G, I and K) and a plant treated with 100 μg g^<b>-1</b> Cd^<b>2+</b> (B, D, F, H, J and L). Cd^<b>2+</b> was detected with the IHC method. Colloidal gold particles were only observed in the cortical tissue of the middle lamella (ML) and the outer surface of the cell wall in the intercellular space (ICS) (B), the outer tangential endodermis wall (D), the membrane along the inner tangential cell wall (F), the plasma membrane near the xylem cell wall (H), PD (J) and curdled proteinaceous material (L) in the vacuole and membrane-bound organelles (M and N) of phloem cells in Cd^<b>2+</b>-positive plants. ICS is the intercellular space, and ML is the middle lamella. The insets display the magnified regions, and the arrowheads indicate Cd^<b>2+</b> depositions.</p