African Journal of Biotechnology Vol. 4 (4), pp. 355-360, April 2005          
ISSN 1684–5315 © 2005 Academic Journals

Full Length Research Paper

Influence of water extract of Mexican sunflower (Tithonia diversifolia) on growth of cowpea (Vigna unguiculata)

Taiwo, L. B.¹* and J. O. Makinde²

¹Soil Microbiology Unit, ²Weed Science Unit, Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor-Plantation, Ibadan, Nigeria.

*Corresponding author.  E-mail: lbtaiwo@yahoo.com.

Accepted 21 January 2005

Laboratory analysis of the water extract of Tithonia diversifolia shoot and root on infra-red spectrometer to determine the phytotoxic potential and greenhouse experiments to evaluate its phytotoxic effect and growth promoting attribute on cowpea (Vigna unguiculata L.) were carried out. T. diversifolia contained some compounds having functional groups such as alcohols, olefins, six-membered ring lactams, ester, aromatic compound which can also be found in sesquiterpene lactones, an allelochemical implicated in phytotoxicity. The extract promoted seedling and plant growth. Bacillus and Streptococcus spp. earlier isolated from the root rhizosphere of T. diversifolia caused some changes in the spectra of the component compounds in the extract. The plant extract promoted growth of cowpea.

Key words: Tithonia diversifolia, sesquiterpene lactones, Infra-red spectrometry; Vigna unguiculata, phytotoxicity.