Pak. J. Bot., 38(3): 673-681, 2006. | Back to Contents | ||||
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Updated: 09-07-09 | ||||
EFFECTS OF HEXAVALENT CHROMIUM (VI) ON ROOT GROWTH AND CELL DIVISION IN ROOT TIP CELLS OF AMARANTHUS VIRIDIS L. J.H. ZOU1, M. WANG1, W.S. JIANG2 AND D.H. LIU1*
Abstract: The effects of different concentrations of Cr(VI) (10-6 M to 10-3 M)
on root growth and cell division in root tips of Amaranthus viridis
L., were studied. Chromium (VI) had toxic effects on the root tip cells
during mitosis, such as colchicine mitoses, anaphase bridges, chromosome
stickiness. Chromosome stickiness implied the high toxicity of Cr(VI).
The mitotic index decreased with increased concentration of Cr(VI),
duration of treatment time and the ratio of anomalous dividing cells
reversed. The results also indicated that the root growth was completely
stopped by 10-3 M Cr(VI) after 24 h treatment time, and slightly inhibited
by 10-4 M Cr(VI) during the whole experiment. Chromium (VI) had a stimulatory
effect on the root growth of A. viridis L. exposed to 10-5 M
Cr(VI) during the entire experiment. The mitotic index in the present
study can be correlated with rate of root growth, suggesting that the
inhibition of root growth resulted from inhibition of cell division.
Department of Botany, College of Chemistry and Life Sciences, Tianjin
Normal University,
Tianjin 300074, P.R. China. |
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