Abstract
We have developed a new bioassay called Dish Pack Method for analyzing volatile allelochemicals. In this method, leaves of plants were put into one of the holes in a 6-well-multi-dish. It is possible to analyze the internal volatile gas collected from the hole with gas-tight-syringe through the septum set up on the holes. By using this method, it was found that Spider flower (Cleome spinosa) contained strong volatile allelochemicals : methyl isothiocyanate (MITC). MITC was one of the strongest natural volatile allelochemicals. Hairy vetch (Vicia villosa Roth) is also allelopathic in the field and we had newly isolated cyanamide as allelochemicals with volatile nature. Yukiyanagi (Spirae thunbergii Sieb.) is a Japanese native tree with allelopathic activity by its fallen leaves. We had isolated cis-cinnamic acid and its derivatives as new allelochemicals. Plant growth inhibitory activity of cis-cinnamic acid is 1000 times stronger than trans-cinnamic acid, and might be new plant hormone.
