The Seasonal Changes Of Secondary Metabolites Phenolic Contents In Urban Greening Plants And Its Response To Air Pollution

Secondary metabolites are produced from secondary metabolism, and they are akind of small molecule organic compounds which are not necessary to the growth anddevelopment of plant. The productions and distributions of secondarymetabolites usually have specificity of species, organs, tissues, and growth anddevelopment periods. In these secondary metabolites, phenolic compounds haveunique physiological characteristics and chemical activities due to the numerousphenolic hydroxyl groups on its molecular structures. They involved in the response ofplants to environmental stress such as intra and/or inter specific competition oratmospheric pollution. The common green plants in Xi’an, Ligustrum lucidum andLigustrum quihoui were studied.9sampling points were selected according to theambient air quality monitoring sites setting by environmental monitoring station ofXi’an. The changes of total phenols and flavonoids contents with the time in two plantsand their relationships with air pollutants were analyzed respectively. This researchmainly gets the following results:（1）The total phenols concentrations were3.56-18.74mg g-1for L. lucidum and8.40-46.10mg g-1for L. quihoui. The concentrations of flavonoids were ranged from5.97mg g-1to72.45mg g-1for L. lucidum and9.83mg g-1to250.68mg g-1for L.quihoui. The total phenols and flavonoids concentrations of L. quihoui weresignificantly higher than that in L. lucidum for each sampling site, it showed thedifference of species of plants had great influence on secondary metabolites phenolic contents. Meanwhile, the total phenols and flavonoids concentrations of both twoplants at same sampling sites in different month had significant differences. Thehighest concentrations of total phenols and flavonoids in L. lucidum and L. quihouiboth appeared in April for every sampling site, and finally, they fluctuates smoothly insome ranges.(2)The results of correlation analysis of total phenols and flavonoidsconcentrations in two plants and air pollutants concentrations of each month in9pointsshowed,the correlations between air pollutants concentrations and both total phenolsand flavonoids concentrations in plants in April-July is not significant, while thesignificant correlations of them were gradually increased after August. There was thesimilar regulation to flavonoids. In addition, the correlations of flavonoids and airpollutants concentrations were more significant than the correlations of total phenolsand air pollutants concentrations.(3)The correlations of concentrations between the average flavonoids of the cityin two plants and O3were both significantly negative, and the correlations ofconcentrations between that and NO2were significantly positive, and the averageflavonoids concentrations of the city in both two plants had extremely significantpositive correlations with the concentrations of SO2, PM10and PM2.5. Concentrationsof the average total phenols of the city in two plants and SO2and PM10weresignificantly positive related, the correlations of the average total phenolsconcentrations of L. lucidum and PM2.5were significantly positive, and the correlationof that were extremely significantly positive related for L. quihoui.