Study For The Allelopathy Of Water Extracts From Solidago Canadensis Roots

Solidago canadensis, a perennial herb, is native to North America, now invasion to Europe, Asia and Australia etc, and introduced to our country as a flower in1935. Due to rapid growth, strong fecundity and competitiveness, S. canadensis was easy to form a single advantage species in non-native community, reduced invaded vegetation richness and led to decline biodiversity, now has been included in directory of important foreign harmful plants in China. Roots of S.canadensis were extracted with water and partitioned against ethyl acetate and n-butanol sequentially. Using germination rate and vigor as seed germination parameters, radicle, plumule elongation and fresh weight change of seedling as seedling growth parameters, we compared the inhibitory effects of the raw aqueous extracts, ethyl acetate extracts, n-butanol extraction extracts, and the water remainder on seed germination and seedling growth of lettuce. Furthermore, the inhibiting effects of n-butanol fractions on lettuce, radish, cucumber, mung bean, onion, rice, wheat and9elution components on lettuce, radish, onion, rice, wheat were tested. The results were as following:1. Among the four fractions, it showed that the original water extract, ethyl acetate fraction and n-butanol fraction of S. canadensis roots all exhibited different allelopathic effect on seed germination and seedling of lettuce, the inhibitory effect of the water remainder on lettuce was not significant, but the inhibition degrees are n-butanol fraction> ethyl acetate fraction> original water extract> water remainder, suggesting that the allelopathy of n-butanol fraction was strongest.2. In the seed germination experiments, n-butanol fraction showed no effect on cucumber and mung bean, and all tested solution at concentration of1.5mg·mL-1exhibited the promotion effect on lettuce and at≥5mg·mL-1significantly inhibited the seed germination of lettuce, radish, onion, rice, wheat (p<0.05). In the seedling growth experiments, it significantly inhibited the seedling growth of7test species at the concentration of5mg·mL-1(p<0.05).3. In the seed germination experiments,8/2and7/3(chloroform/methanol) elution fractions exhibited strongly inhibition effects on the seed germination of5test species and had no effect on the seedling growth (p<0.05), among which the allelopathy of8/2(chloroform/methanol)elution fraction was strongest. In the seedling growth experiments,5/5,4/6and3/7(chloroform/methanol)elution fractions had no effect on the seed germination of5test species and exhibited strongly inhibition effects on the seedling growth (p<0.05), among which the allelopathy of5/5(chloroform/methanol)elution fraction was strongest.