Assessment of Allelopathic Potential of Melastoma malabathricum L. on Radish raphanus sativus L. and Barnyard Grass (Echinochloacrus-galli)

Melastoma malabathricum L. is a weedy invasive shrub in arable lands, abandoned farmlands, secondary forest openings and derelict areas in Malaysia. Some allelochemicals present in this plant extracts may, directly, prevent or promote germination when environmental conditions are conducive to growth and establishment. It may have an important role, indirectly, in determining plant community structures. The aqueous extract and methanol extracts, were assayed for the aqueous extract of fresh materials with concentrations of 0, 50,100,150 and 200 gl(-1) and at aqueous of oven dried materials extract with concentrations of 40,80,120,160,and 200 gl(-1) The crude methanol extracts were prepared using extract concentrations of 10.8, 14.28, 18 and 30 gl(-1) of shoot and root materials. The extracts were tested with the widely used radish sced barnyard grass seed. Radish seed germination was inhibited at concentrations ranging from 200 gl(-1) in the extract aqueous of dried materials and in the methanol extract concentrations of 14.28 and 30 gl(-1) .The inhibition of root and shoot growth was also observed in the Barnyard grass seed. Both species were susceptible to allelopathy by extracts isolated from shoot and root of M. malabathricum and also their race of germination, root length and shoot length in were decreased upon the application of both type of extractions. The results from this study strongly Suggest that allelopathy may be a possible mechanism controlling the timing of barnyard grass germination and seedling establishment.