Study on the Effects and Mechanism of Exogenous Phenolic Acids on Potato's Growth and Development

This paper probed the effects and mechanism of exogenous phenolic acids on potato's growth and development. Para hydroxy benzoic acid,vanillic acid and ferulic acid are the three most important allelochemicals( phenolic acids) in potato continuous cropping soil,when the potato seedlings were irrigated with the three kinds of phenolic acids solution and its mixture respectively,the plant height,stem diameter,aerial stem number,stolon number and root length were reduced significantly,and at the same concentration of phenolic acid solution,the inhibition of the their mixture was stronger than that of each phenolic acid solution. The results also showed that the treatment of exogenous phenolic acids significantly reduced the potato's root activity,leaf chlorophyll content and leaf net photosynthetic rate,and the inhibitory effects increased significantly as the phenolic acid solution concentration increased from 50 mg / L to 200 mg / L. These effects described above should play a direct and important role in the growth and development of the plants. The tests about the lipid peroxidation of the potato plantlets' leaves showed that the treatment of exogenous phenolic acids increased the leaves' MDA content significantly,and were corresponds to the decline in antioxidant enzyme activity,as the concentration of exogenous phenolic acids solution increased( from 100 mg / L to 200 mg / L) the effect was strengthened,and the mixed phenolic acids' effect was the most significant under the sameconcentration. So it can be concluded that exogenous phenolic acids treatments caused continuous and significant stress on the potato's leaves,and resulted in the reduction in the function of antioxidant enzyme system,and thus resulted in the increase in lipid peroxidation degree. The results were corresponded to the results that the exogenous phenolic acids treatment inhibited the plants growth,root activity and leave net photosynthetic rate. The above results of this paper may promote the understanding and regulation in potato continuous cropping obstacle.