Effects of IAA with Malefic Hydrazide and Colchicine on Root Tip Mitosis

Abstract

The effects of maleic hydrazide MH, indole-3 acetic acid IAA and colchicine were studied on the mitotic division and induction of chromosomal abnormality in Allium cepa root tips treated with 25, 50 and 75 ppm concentrations for 4, 8 and 12 hour durations. Inhibition of mitosis was brought about under all treatments except IAA which at lower concentration stimulated the division. For the inhibition of mitosis IAA was most effective and MH was least effective. The capacity to produce chromosomal abnormality was evidenced by the presence of chromosome and chromatid breaks, bridge formation, spindle fibre inhibition resulting in the formation of polyploid cells; chromosome erosion, lagging of chromosomes, micronuclei, stickiness and swelling of the nucleus.