PLANT-GROWTH FACTORS PRODUCED BY THE FUNGUS ALTERNARIA-BRASSICAE

High-performance liquid chromatographic analysis of a crude extract of Alternaria brassicae gave three compounds affecting plant growth. Based on spectral analyses, these compounds were identified as N-methyl-2,5-dimethyl-N'-cinnamoylpiperazine, 2-hydroxy-1'-methylzeatin and 3-carboxy-2-methylene-4-pentenyl-4-butenolide. Treatment of seedlings of canola/rapeseed with N-methyl-2,5-dimethyl-N'-cinnamoylpiperazine and 3-carboxy-2-methylene-4-pentenyl-4-butenolide reduced their growth whereas 2-hydroxy-1'-methylzeatin increased the growth of seedlings. Moreover, treatment of canola/rapeseed cotyledons with 2-hydroxy-1'-methylzeatin increased the chlorophyll content, whereas the other two compounds induced chlorosis.