Abstract
Plants with allelopathic properties were screened among Japanese medicinal plants using the lettuce seed germination and seedling growth tests and Fusarium oxysporum spore germination and hyphal growth tests. Plants with allelopathic properties were more frequently selected among these medicinal plants than among common crops and weeds. The strongest activity which was observed in Pulsatilla cernua (okina-gusa) and Crematis paniculata (sen-nin-sou), both Ranunculaceae, followed by Inula helenium (oo-guruma), Thymus vulgaris (French thyme), Ammi visnaga, Laurus nobilis (laurel) was manifested by both plant growth inhibition and fungicidal properties. Water extracts of Allium tuberosum and Allium sativa and methanol extracts of Glycyrrhizae glabra and Curcuma longa displayed a strong anti-fungal activity, but did not affect plant growth. On the other hand, Phytolacca americana, Cinnamomum sieboldii, and Mentha piperita exhibied a strong plant seed germination and seedling growth inhibition, but had no effect on fungi.
