A phytotoxic compound, identified as 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (curvulinic acid), was isolated from liquid cultures of the phytopathogenic fungus Nimbya alternantherae. The activity of curvulinic acid on seed germination and seedling growth of Capsella bursa-pastoris was evaluated. Percentage seed germination of C. bursa-pastoris was decreased with increasing concentrations of curvulinic acid. The compound had stronger inhibitory effects on root length than shoot length. At a concentration of 600 μg·mL−1, curvulinic acid caused 73.5% and 66.7% growth inhibition on roots and shoots with IC50 values of 204.7 and 281.1 μg·mL−1, respectively. The finding of curvulinic acid in N. alternantherae and its herbicidal activity are reported here for the first time.

中文翻译：

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轮花参中曲霉酸的除草活性

从植物病原真菌 Nimbya alternantherae 的液体培养物中分离出一种植物毒性化合物，被鉴定为 2-(2-acetyl-3,5-dihydroxyphenyl) 乙酸 (curvulinic acid)。评价了curvulinic acid对Capsella bursa-pastoris种子萌发和幼苗生长的活性。C. bursa-pastoris 的种子发芽率随着花糖酸浓度的增加而降低。该化合物对根长的抑制作用比对芽长的抑制作用强。在600 μg·mL-1浓度下，curvulinic acid对根和茎的生长抑制率为73.5%和66.7%，IC50值分别为204.7和281.1 μg·mL-1。本文首次报道了交替南草中花草酸的发现及其除草活性。