Patricia Joy A. Aldeguer, Stephanie S. Katalbas, Fabini D. Orata (January 2003)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
This study determined the effects of different exposure times two ultraviolet radiation on the mitotic activity on the onion root tip. Specifically, it aimed to determine the mitotic indices of the onion root tips when exposed to ultra violet radiation for 5, 10, and 15 minutes. It also compared the mitotic indices of the onion root tips when exposed to ultraviolet radiation for 5, 10, and 15 minutes. It further determined the significant difference among the mitotic indices of the onion root tips exposed to ultraviolet radiation for 5, 10, and 15 minutes. It was hypothesized that there is no significant difference among mitotic indices of the onion root tips when exposed ultraviolet radiation for 5, 10, and 15 minutes. A Completely Randomized Design was used to determine the effects of varying exposure periods to ultraviolet light or radiation on the mitotic activity of onion root tips. The independent variables of this study were the different exposure times of the onions to ultraviolet radiation, while the dependent variables were the observed changes in the mitotic activity of the onion root tips. Onions were randomly chosen and purchased at tha Iloilo Central Market and were then exposed to UV radiation. There were three treatment groups namely 5 minutes, 10 minutes, and 15 minutes exposure to ultraviolet radiation. Data gathered were analyzed using the mean and standard deviation, the One Way Analysis of Variance, and the Scheffe test.
Based on the results of this study, exposure to UV radiation in a given period of time has significant effect on the mitotic activity of onion (Allium cepa) root tips. The longer the period of exposure to UV radiation, the more damaged cells, the lower is the mitotic index, and there is less mitotic activity. The shorter the exposure period, the less damaged cells, the higher mitotic index of the root tip, and there is more mitotic activity.