Cytological effects of oxytocic agents on mitotic chromosomes of Allium cepa
Two synthetic (oxytocin and ergometrin) and one crude (Xylopia aethiopica extract) oxytocic agents, in two formulations were tested on root tip mitosis of Allium cepa. Both synthetic and crude oxytocic agents had depressive effect on the mitotic index and percentage of mitotic phases. There was an accumulation of prophase at the expense of the other phases. Diverse kinds of abnormalities were observed in different mitotic phases. These include disturbed prophase, spindle inhibition, star metaphase, chromatid bridge, precocious chromosome and even nuclear disintegration. The percentage of abnormal cells increased with increase in concentration of treatment drugs and duration of treatment. The possible reasons for the low mitotic index, prophase accumulation and low percentage of mitotic phases as well as increased abnormities at high concentrations have been discussed.
Keywords:Oxytocic agents, Cytology, Chromosomes, Mitotic index, Allium cepa.
Agro-Science Vol. 5 (2) 2006: pp. 1-6