Abstract: Using rotational quadratic regression design,effects of pH,cinnamic acid,p-hydrobenzoic,and vallic acids on the growth of Cunninghamia lanceolata and Raphanus sativus seedlings were examined. Results showed that the growth of C. lanceolata seedlings decreased as the pH value of solutions decreased,while the growth of C. lanctolata seedlings increased as the concentration of cinnamic acid,p-hydrobenzoic,and vallic acids in solutions decreased. As far as the effects of phenolics on the growth of C. lanctolata seedlings are concerned,cinnamic acid was the most obvious,p-hydrobenzoic acid was less,and vallic acid was the least. Significant interaction was observed between the pH value and cinnamic acid,and between cinnamic acid and vallic acid,and between p-hydrobenzoic acid and vallic acid. The effects on the growth of R. sativus seedlings were similar to the C. lanctolata seedlings. However,the effect of p-hydrobenzoic acid on the growth of R. sativus seedlings was the most oboious,cinnamic acid was less,and vallic acid was the least. Significant interaction was detected between pH and all three phenolics,and between cinnamic acid and vallic acid when the target plant was R. sativus seedlings.

Key words: Watershed, Wetland landscape, Fragmentation process