Abstract:

In order to determine the optimum culture conditions of Phoma herbarum for the toxin production, the author acquired the crude toxin of the Phoma herbarum by the way of organic solvent extraction, and the extraction condition was optimized by the seed germination and seedling stage stabbing inoculation. The results showed that this crude toxin showed high inhibitory activity, and the best extract organic solvent was ethylacetate. Besides the best conditions of toxin production of this strain were as follows: the fermentation temperature was 32℃, culture time was 14 d, agitation was150 r/min. The seed germination rate was 26.09% and the lesion area of the leaf reached 6.85 mm2 when the concentration of toxin was 1000 μg/mL. Obvious difference of herbicidal activity is shown with different extract organic solvent and culture condition which exerted a great influence on the activity of the crude toxin of Phoma herbarum.Key words: Phoma herbarum; toxin; Toxin-producing activity