Antimicrobial and phototoxic effect of a substance isolated from water hyacinth

ABSTRACT

The application of antimicrobial substance, isolated from ethyl ether extract of water hyacinth, to soil inhibited and delayed seed germination and seedling growth of cotton plants. The antimicrobial substance reduced the number of total bacteria, fungi, streptomycetes, azotobacter, N-fixing clostridia, nitrifiers, aerobic cellulose decomposers and phosphate dissolving bacteria in the rhizosphere during the first period of plant growth. The inhibitory effect of such substance on seed germination and rhizosphere microflora disappeared after 20 days from addition to soil. The inhibitory effect of the antimicrobial substance on cotton seedling growth was to some extent influenced by soil type, being more pronounced in sandy soil