Abstract: Dry leaf of Hyptis suaveolens Poit was extracted with water and methanol and the effect on seed germination and seedling growth were determined in Pennisetum setosum and Mimosa invisa. The water extract significantly reduced P. setosum seed germination and strongly inhibited shoot and root lengths of both P. setosum and M. invisa. The inhibition percentages increased with the increasing of dry leaf ratios of the extracts. Shoot growth of P. setosum and M. invisa seedling was less sensitive to the extract than root growth was. The lower leaf ratios extracts (1:80 and 1:40) did not reduce shoot length of both weeds, in contrast, the 1:80 ratio extract promoted P. setosum shoot length 16.97% of untreated control. In this study, P. setosum was more susceptible to H. sauveolens leaf water extract than M. invisa. The methanol extraxts of H. suaveolens leaf significantly inhibited seed germination and seedling growth of both P. setosum and M. invisa and the inhibitory effects were higher than those of the water extracts. This might indicate solubility of the allelochemicals in H. suaveolens leaf better in methanol than in water. It is interesting to study further on allelopathy of this plant for the practical use in agricultural pest management.
Boonrod Chatiyanon, Tawatchai Tanee, Chusri Talubmook and Chalermchai Wongwattana, 2012. Effect of Hyptis suaveolens Poit Leaf Extracts on Seed Germination and Subsequent Seedling Growth of Pennisetum setosum (Swartz.) L.C. Rich and Mimosa invisa Mart. Agricultural Journal, 7: 17-20.