Effects Of Allelochemicals On Growth Of Seedlings And Soil Enzyme Activity Of Pogostemon Cablin

Pogostemon cablin is a plant of the Lamiaceae family, and it’ s a traditional Chinese medicine,which is cultivated extensively in the Phi lippies,Malaysia,India,China and other Southeast Asian countries. Pogostemon cablin is the important components of 30 kinds of proprietary Chinese medicine in our country, the essential oil has bacteriostatic antiviral effect; At the same time, it is also the important raw material of light chemical industry. Pogostemon cablin has been widely used to produce raw materials for cosmetics and insecticides. However,Pogostemon cablin has suffered from very serious consecutive monoculture problems, which leaded to severe diseases, significantly reduced biomass and quality of overground part (leaves), or low harvest rate, seriously affected the production of patchouli. Thus, it is necessary to commence studies on the causes and mechanism of its continuous cropping obstacles. In this study, Hainan Pogostemon cablin as research material was used to study the allelopathic toxicity of Pogostemon cablin and the effects of allelochemicals on soil enzyme activities in the rhizosphere. The results showed that Pogostemon cablin continuous obstacle to provide theoretical basis and technical support.The main conclusions are mainly as follows:(1) In this study, the effects of six allelochemicals of benzoic acid, vanillic acid,cinnamic acid, p-hydroxybenzoic acid, salicylic acid and malonic acid on growth of potted Pogostemon cablin seedlings grown in April were studied. The results showed that all the allelochemicals affected the growth of Pogostemon cablin seedlings in different degrees,and inhibited the growth of Pogostemon cablin seedlings. At the same concentration, the allelopathic effect of Pogostemon cablin was: p-hydroxybenzoic acid> cinnamic acid>salicylic acid> benzoic acid> malonic acid; different concentrations of allelochemicals,Low concentration showed no significant change or less impact, high concentration inhibition effect is more obvious.(2)The allelopathic effects of six allelochemicals on the activities of enzymes (MDA.POD, SOD) of Pogostemon cablin seedlings were not obvious after the seedlings were treated with low concentration of allelochemicals. The inhibition effects weren’ t obvious.The protective enzyme and membrane system of Pogostemon cablin seedling leaves increased the activity of antioxidant enzymes, and the inhibition effects were the most significant.(3)The six allelochemicals inhibited soil polyphenol oxidase, phosphatase, urease,sucrase and protease. The inhibitory rates of polyphenol oxidase, phosphatase, urease and sucrase increased with the increase of the concentration, while the inhibition rate of protease activity decreased with the increase of the concentration.