cadmium

microtubule

mitosis

Salix matsudana Koidz

cell damage

Pollution

Contamination

Phytoremediation

Heavy metals contamination of soil

Heavy metals contamination of plants

The toxic effects of Cd on microtubule (MT) organization in root tip cells of S. matsudana were investigated in the present study using tubulin immunolabeling and fluorescence microscopy. Cell damage and expression level of the SmTUA1 gene in the root tips were also examined by means of propidium iodide (PI) staining and quantitative real-time PCR (qRT-PCR) technology. The MT arrays were very sensitive to Cd. At interphase, under 50 μmol/L Cd treatment for 48 h, some cortical MTs were discontinuous, inducing numbers of differently sized fragments. With increased Cd concentrations and duration of treatment, peripheral MTs appeared to be broken gradually, and the degree of disorder was enhanced. Spindle fibers even formed condensed MT at 10 μmol/L Cd for 48 h. During anaphase/telophase, there was a small part of MT absent, MT fibers were stuck to each other (even forming lumps) and could not form phragmoplast at 50 μmol/L Cd for 48 h. The cell damage of S. matsudana root tips increased with enhanced Cd concentrations and prolonged treatment time. Expression level of SmTUA1 analyzed by qRT-PCR further validated the results by indirect immunofluorescence staining. The data obtained here will be very useful to understand the mechanisms of Cd-induced cell toxicity.