Mitotic Activity in Cowpea (Vigna unguiculata (L.) Land Race “Olaudi” Walp) in Nigeria

Peggy Obaseojei Willie, Peter Osobase Aikpokpodion

Department of Genetics and Biotechnology, Faculty of Science, University of Calabar, Calabar, Nigeria.

DOI: 10.4236/ajps.2015.68123                

Abstract

Cowpea, Vigna unguiculata is a major staple for millions of households in the tropics. A cowpea land race, “Olaudi” collected from South-Eastern Nigeria was investigated for mitotic indices during cell division. Root tips were pre-treated with 8-hydroxyquinoline for three hours, fixed in Carnoy’s solution (alcohol-acetic acid solution 3:1 v/v) for 24 hours, hydrolysed in 1 NHCl and squashed in aceto-orcein. Various stages of mitosis were recorded to determine mitotic activity in dividing cells. Results obtained showed that active cell division occurred between 7.00 AM and 2.00 PM but peaks between 11.00 AM and 1.00 PM. Although cells at the prophase stage were in a continuum, they became observable between 8.00 AM and 3.00 PM, but greater proportion of cells was observed at 12.00 PM. Cells at metaphase were generally observed during a six hours period between 8.00 AM and 1.00 PM, but the peak period was 11.00 AM. Mitotic activity at anaphase commenced around 10.00 AM late morning but plateaus for two hours early afternoon between 12.00 PM and 2.00 PM. Telophase activity was mostly observed at 11.00 AM within a five hour period between 9.00 AM and 2.00 PM. Mitotic index peaked at 1.00 PM with 65.3% of cells in active cell division, with a concomitant high mean germination percentage (63.5%). This study provides useful basic information to guide further cytogenetics research in the genetic improvement of this local cowpea landrace.

Keywords

Mitotic Index, Mitosis, Cowpea, Germination Percentage

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Purseglove, J.W. (1988) Tropical Crops: Dicotyledons. Longman Group, London.
[2]	Gogile, A., Andargie, M. and Muthuswamy, M. (2013) Screening Selected Genotypes of Cowpea [Vigna unguiculata (L.) Walp.] for Salt Tolerance during Seedling Growth Stage. Pakistan Journal of Biological Sciences, 16, 671-679.
[3]	Padulosi, S. (1993) Genetic Diversity, Taxonomy, and Ecogeographic Survey of the Wild Relatives of Cowpea (V. unguiculata). PhD Thesis, University of Louvain La Neuve, Belgium.
[4]	Duke, J.A. (1981) Vigna unguiculata (L.) Walp. Species unguiculata: Handbook of Legumes of World Economic Importance. Plenum Press, New York. http://dx.doi.org/10.1007/978-1-4684-8151-8
[5]	Udensi, O., Edu, E.A., Ikpeme, E.V., Ebiwgai, J.K. and Ekpe, D.E. (2012) Biometrical Evaluation and Yield Performance Assessment of Cowpea (Vigna unguiculata (L.) Walp) Landraces Grown under Lowland Tropical Conditions. International Journal of Plant Breeding and Genetics, 6, 47-53. http://dx.doi.org/10.3923/ijpbg.2012.47.53
[6]	Wanatabe, I., Hakoyama, S., Terao, T. and Singh, B.B. (1997) Evaluation Methods for Drought Tolerance of Cowpea. In: Singh, B.B., Mohan-Raj, D.R., Dashiell, K.E. and Jackai, L.E., Eds., Advances in Cowpea Research, Co-Publication of International Institute of Agriculture (IITA) and Japan Institute for Agricultural Sciences (JIRCAS) IITA, Ibadan, 141-146.
[7]	Singh, R.J. (1993) The Handling of Plant Chromosomes. Plants Cytogenetics, 4, 7-24.
[8]	Isabelle, D., Leon-Kloosterzie, K.M. and Koomneel, M. (2000) Influence of the Testa on Seed Dormancy, Germination and Longetivity in Arabidopsis. Plant Physiology, 122, 403-413. http://dx.doi.org/10.1104/pp.122.2.403
[9]	Eaglesham, A.R., Ayanaba, J.A., Rama V.R. and Eskew D.L. (1992) Mineral N Effects on Cowpea and Soybean Crops in Nigeria Soil: Amounts of Nitrogen Fixed and Accrual to the Soil. Plant and Soil, 68, 183-186. http://dx.doi.org/10.1007/BF02373704
[10]	Fatokun, C.A., Tarawali, S.A., Singh, B.B., Kormawa, P.M. and Tamò, M. (2002) Challenges and Opportunities for Enhancing Sustainable Cowpea Production. Euphytica, 91, 181-187.
[11]	Wang, L. and Ruan, Y.L. (2013) Regulation of Cell Division and Expansion by Sugar and Auxin Signalling. Frontiers in Plant Science, 4,163.
[12]	Darbelley, N.D., Driss-Ecole, D. and Perbal, G. (1989) Elongation of Mitotic Activity of Lentil Roots Grown in Microgravity. Plant Physiological Biochemistry, 27, 341-347.
[13]	Driss-Ecole, D., Schoevaert, D.D., Noin, M. and Perbal, G. (1994) Densitomeric Analysis of Nuclear DNA Content in Lentil Roots Grown in Space. The Cell, 81, 59-64.
[14]	Okoli, B.E. (1992) Field, Herbarium and Laboratory Techniques. Mbeyi and Associates (Nig.) Ltd., Port Harcourt, 239 p.
[15]	Adesoye, A.I. and Nnadi, N.C. (2011) Mitotic Chromosomes Studies of Some Accessions of African Yam Bean, Sphenostylis sternocarpa (Hochst. ex. A. Rich.) Harm. African Journal of Plant Science, 5, 835-841. http://dx.doi.org/10.5897/AJPS10.199
[16]	Bennet, M.D., Smith, J.B. and Heslop-Harrison, J.S. (1982) Nuclear Amount in Angiosperm. Proceedings of the Research Society of London, 216, 179-199. http://dx.doi.org/10.1098/rspb.1982.0069
[17]	Klug, W.S., Cummings, M.R. and Spencer, C.A. (2006) Concepts of Genetics. 8th Edition, Pearson Education International, Upper Saddle River, NJ. ISBN 0131918338, 676 p.
[18]	Ekanem, A.M. and Osuji, J.O. (2006) Mitotic Index Studies on Edible Cocoyams (Xanthosoma and Colocasia spp.). African Journal of Biotechnology, 5, 846-849
[19]	Osuji, J.O. and Owei, S.D. (2010) Mitotic Index Studies on Treculia africana Decne. Austria Journal Agricultural Engineering, 1, 25-28.