Cytological Effects of 5- Amino Uracil on Allium cepa L. roots

Abstract

5- Amino Uracil is a structural analogue of pyrimidine. In this work the cytological effects of 5-AU has been evaluated in the root tip cells of Allium cepa L. following treatment with different concentrations for different durations. Microscopical observation of the cells revealed that 5-AU has considerable clastogenic activities as evidenced by altered MI (Mitotic index) values as well as occurrence of different types of chromosomal abnormalities. Inspite of such abnormalities, the treated cells when allowed to recover for different periods there results a synchronous mitotic wave. Following 32.5 h and 33h of recovery synchronous prophase and metaphase populations were obtained. It has been further concluded that the recovery time required to achieve such synchronization is not independent of the duration of treatment as concluded by some earlier workers.