Abstract:

In the 35 diferent Pestalotia funerea strains，the toxicity of metabolic substances of the strain PF-11 (from Pinus tabulaeformis) was the highest，and that of strain PF-2 (from P. massoniana) was second. Using PF-11 as original strain，ten mutants were obtained by 3 continuous times under ultraviolet muta genesis dosage which was less than lethal dosage. Three active fractions with the Rf values of 0.83，0.79，0.80 were separated from P11 metabolic substances by gel H60 column chromatography with nbutanol∶methanol∶water (4∶1∶2) as the mobile phase．Four active fractions with the Rf values of 0.83，0.79，0.80，0.60 were purified from the ultraviolet mutant of P11-4，which showed one more active fraction was produced affer treated with ultraviolet. The formula was C₁₂H₂₃O₉N(M r=325) with the structure of O O O NHCH₂CH₂CH₃indentified by IR，MS and 1HNMR. The ultraviolet mutant were used to investigate their weeding effect, and the results showed that three mutants were negative with no toxicity to objective weed； five mutatants didnt increased obviously on toxicity； however PF11-4 and PF11-6, were positive mutants and their toxicity against objective weed were increased obviously.

Key words: Pestalotia funerea, mutation breeding, bioweeding, parasitic seed plant, weed