Allelopathic Potential of Clerodendrum viscosum Vent. in Relation to Germination and Seedling Growth of Weeds

Abstract

The activity of decaying plant-parts of Clerodendrum Viscosum and field soils collected beneath Clerodendrum plants have been studied on the seed germination and root and hypocotyl growth of five weeds, viz. Abutilon indicum, Amaranthus spinos, Cassia Sophera, C. tora and Tephrosia hamiltonii . Germination inhibitions are almost uniform in soil samples of both July and December, although the root and hypocotyl growth of A. spinosus is adversely affected by the December soil collection and similar growth of Abutilon indicum and T. hamiltonii strongly inhibited by underground soils of the season. Decaying roots seem to be most inhibitory among the three plant-parts. While no inhibition to A. indicum and C. tora results from mixing decaying leaves and stems with soil, there is inhibition to C. Sophera from the admixture of either plant material and T. hamiltonii from leaf/soil mixture and not stem/soil mixture. As the leaves of Clerodendrum form the most consistent source of the natural chemical retardant, these are analysed and the presence of a terpene compound (clerodin) has been suspected in carrying out the allelopathic effect.