Comparative Effects of Colchicine, 8- Hydroxyquinoline and Paradichlorobenzene on the Lengths of Mitotic Chromosomes in Allium cepa L.
*1Ekong, N. J., 2Akpan, G. A., 2Akpabio, K. E. and 1Isa, R. T.
1. Department of Biological Sciences, Federal University Wukari, Taraba State, Nigeria.
2. Department of Botany & Ecological Studies, University of Uyo, Akwa Ibom State, Nigeria.
Abstract: Studies were carried out to assess the comparative effects that 0.5% aqueous solution of colchicine, 0.004M 8-hydroxyquinoline and saturated solution of paradichlorobenzene may have on the lengths of mitotic chromosomes. The somatic chromosomes were studied in root meristems of Allium cepa L. Karyometric analysis of the onion root tips chromosomes revealed a chromosome number 2n = 16. The highest mean haploid chromosomes length of 8.443μm was observed for chromosomes treated with 0.5% colchicine, while 7.168μm and 7.188μm were recorded for chromosomes treated with 0.004M 8-hydroxyquinoline and paradichlorobenzene respectively. Analysis of Variance showed that there were significant differences among the treatments (p<0.05) in the lengths of chromosome 1, 2, 3 and 4 while there were no statistically significant differences (p<0.05) in the lengths of relatively shorter chromosomes (5 – 8) due to the three pre-treatments. Least Significant Difference (LSD) test for chromosomes 1-4 showed that these chromosomes pre-treated with paradichlorobenzene where significantly shorter (p<0.05) than those treated with colchicine, however there were no significant differences between these chromosomes treated with paradichlorobenzene and 8-hydroxyquinoline. Although advantageous, the differential contraction rates due to the three pretreatments, which may have been due to differences in the concentrations of the reagents and position of the sampled cells in the cell cycle, calls for a standardization of measurements of pre-treated chromosomes.
Keywords: Chromosome lengths, mitosis, haploid complement, colchicine, 8-hydroxyquinoline, paradichlorobenzene.
Pages: 125 – 135 | Full PDF Paper
The effect of Metarhizium robertsii and Bacillus thuringiensis against Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)
1. Laboratory of Plant Protection and Pharmacology, Department of Agricultural Technology, Technological Educational Institute of Western Greece, Amaliada Greece.
2 . Department of Pharmacy, School of Health Sciences, University of Patras, Patras 26504, Greece.
Abstract: Susceptibility of Helicoverpa armigera populations to Metarhizium robertsii and Bacillus thuringiensis (Bt) were evaluated under laboratory conditions. Helicoverpa armigera larvae were treated individually and in combination with a single dose rate of B. thuringiensis (Bt: 1 ml/L) and three conidial suspensions viz. 1×103, 1×105 and 1×107 spores/ml of M. robertsii. Compared with the untreated checks, pupation, adult emergence and egg eclosion of both instars larvae were significantly reduced in combined application treatment of M. robertsii (1×107 spores/ml) and B. thuringiensis (1 ml/L). The results indicate that the entomopathogenic fungi and the insecticidal protein produced by B. thuringiensis can be used as potential biocontrol agents for the management of maize stem borer.
Keywords: Bacillus thuringiensis, biological control, Helicoverpa armigera, Metarhizium robertsii, tomato.
Pages: 136 – 146 | Full PDF Paper
Tsikalakis, G. J.
Department of Nutrition-Dietetics, Technological Educational Institution of Crete, Trypitos, 72300 Sitia Crece.
Abstract: The philosophical approach of ecology is an issue that is studied at the level of philosophyethics principles. The moral dimension of the subject is not limited to the formulation of reflection, but to the whole of human values and good human behavior in the matter of food. The aim of the work is to explore concepts and concerns that link nutrition and ecology to the philosophical ethics with current food and how environmental education can integrate the environmental footprint of food into moral ethics.
Keywords: Philosophy – Ethics, Food, Environmental Footprint of Food – Teaching.
Pages: 147 – 158 | Full PDF Paper