PHYTOTOXIC ACTIVITY OF SELECTED WATER-SOLUBLE METABOLITES OF FUSARIUM AGAINST LEMNA-MINOR-L (DUCKWEED)

Phytotoxicity and inhibitory effects of the fusarial toxins fumonisin B1 (FB1) [m.p. 103-105-degrees-C], fusaric acid [m.p. 106-107-degrees-C], butenolide (4-acetamido-4-hydroxy-2-butenoic acid lactone) [116-117-degrees-C], 9,10-dihydroxyfusaric acid [m.p. 150-155-degrees-C], and moniliformin on chlorophyll synthesis in the aquatic macrophyte Lemna minor (duckweed) were examined. FB1 proved to be most active, reducing the growth of L. minor fronds and their ability to synthesize chlorophyll by 53% and 59%. respectively, at 0.7-mu-g/ml. The growth rate of L. minor was reduced 59% by 6.7-mu-g/ml fusaric acid, 62% by 66.7-mu-g/ml butenolide, and 22% by 66.7-mu-g/ml 9.10-dihydroxyfusaric acid. Moniliformin was the least phytotoxic to L. minor, with only a 16% suppression of growth rate and a 54% reduction in chlorophyll at 66.7-mu-g/ml.