Abstract
Aqueous extracts from various plant / litter components of Guaicum officinale L. significantly inhibited germination of wheat (Triticum aestivum L.) except bark which had very mild inhibitory effect. The degree of germination inhibition was proportional to the concentration of the extracts. Bark extract was the least inhibitory. Suppression of germination under influence of the extracts employed was in the following order of toxicity as - Pericarp > Flowers > Yellow leaves > Green leaves > Green fruits > Bark. Seedling growth in terms of plumular elongation, number of seminal roots, average length of seminal root in a seedling, total length of seminal roots per seedling and the biomass accumulated over three days of growth in seedlings per Petri plate indicated significant reduction in seedling performance under influence of the extracts of plant components such as abscised yellow leaves, abscised floral parts, pericarp of the dehisced fruits, and green leaves. The abscised yellow leaves and floral parts were the highly toxic litter components. Bark, on the other hand had no inhibitory effect on seedling growth – rather it stimulated the plumular growth significantly. Extract of green fruit had very mild inhibitory effects on wheat seedlings.
