KENAF EXTRACT AFFECTS GERMINATION AND POST-GERMINATION DEVELOPMENT OFWEED, GRASS AND VEGETABLE SEEDS

Metabolites produced by one organism can affect development of other o rganisms. Kenaf(Hibiscus cannabinus L.) is used in products which put it in direct contact with other plants. This project was designed to d etermine whether kenaf plant extracts can affect germination and devel opment of vegetable, grass and weed seeds. Frost-killed kenaf was chip ped and either immediately frozen (weathered 0 months) or applied to t he soil in mats in December and allowed to weather for 2 or 4 months. Kenaf samples, weathered from 0 to 4 months, were ground and soluble m aterials were extracted with distilled water. Seeds of cucumber (Cucum is sativus L.), green bean (Phaseolus vulgaris L.), tomato (Lycopersic on esculentum Mill.), redroot pigweed (Amaranthus retroflexus L.) and annual Italian ryegrass (Lolium multiflorum Lam.) were exposed to 0, 1 6.7, 33.3, and 66.7 g/l of kenaf extract. Distilled water and three co ncentrations of polyethylene glycol (PEG) were included as controls. A fter 7 days, total germination and hypocotyl and radicle lengths were determined. Extracts of kenaf weathered up to 4 months, especially at the highest concentration, reduced germination in pigweed by 50-70%. G ermination in tomato and ryegrass was reduced by 30% when exposed to t he highest concentration of unweathered kenaf. As length of time of we athering of kenaf increased, germination and length of most plants inc reased. This suggests that, over time, the detrimental compounds in ke naf were leached or otherwise changed so that they had no effect or be came beneficial. Non-weathered kenaf or its extracts, may be employed to suppress weeds. Alternatively, weathered kenaf tissue or extracts m ay stimulate germination and post-germination development of existing economic crops. Published by Elsevier Science B.V.