Study On The Ability To Inhibit Bacteria And Photosynthesis Of Stratified Mixed Stands At Sun Yat-sen Mausoleum Scenic Spot

The ability to inhibit bacteria and the character of photosynthesis of the main inducing trees of different stratified mixed stands were researched at Sun Yat-sen Mausoleum scenic spot. In order to offer the basis of the urban forests on the collocation of ecological greening and bacteriostasis function, and introduction of trees. The main conclusions were drawn as follows:1) The results showed that the rate of inhibiting bacteria was over 80% at 10:00 a.m in different stratified mixed stands of Taiwania flosiana,Cinnamomum camphora and Mchelia platypetala. In the atmosphere in nine mixed forests, the content of bacteria decreased obviously from 1328 to 1817/m3 and the range of rates of inhibiting bacteria was 64.4% to 88.3%. The rate of inhibiting bacteria was over 80% in different mixed forests of Taiwania flosiana,Cinnamomum camphora , Mchelia maudiae, Manglietia yuyuanensis and Mchelia platypetala. In the atmosphere in nine mixed forests at 15:00, the content of bacteria decreased obviously from 1398 to 1975/m3 and the range of rates of inhibiting bacteria was from 65.5% to 92.7%.2) The ability to inhibit bacteria of different stratified mixed stands was fluctuant in the year. The content of pollutant bacteria decreased obviously from 2018.2 to 4246/m3 and the range of rates of inhibiting bacteria are from 21.3% to 91.8% in the atmosphere in different stratified mixed stands of M.maudiae, M. chapensis and M. yuyuanensis. The results of analysis of double variance showed that there were very remarkable differences in different stratified mixed stands.3) The daily course of net photosynthetic rate of three trees had one peak, and their peaks of M.maudiae and M. yuyuanensis appeared at 12:00, but the peak of M. chapensis appeared at 10:00. The results of analysis of variance showed that there was significantly positive correlation (P<0.01)between Pn and PAR,T,Gs,Tr, but there was significantly negative correlation between Pn and Ci (P<0.01),and RH (P<0.05). There was significantly positive correlation (P<0.01)between Tr and PAR,Gs,T, but there was significantly negative correlation (P<0.01) between Tr and Ci. Compared with photosynthesis data of M. maudiae and M. chapensis, some photosynthetic parameters of M. yuyuanensis such as LSP, YAQY are the highest, while LCP and Rd are the lowest. Therefore, the adaptation of M. yuyuanensis is stronger than others′.4) The results showed that in M. maudiae, there were negative correlations among RH and Tr,RH and Gs, and there was significantly positive correlation between RH and water use efficiency. In M. chapensis, there was positive correlation between PAR and water use efficiency. In M. yuyuanensis, there was significantly positive correlation between PAR and Pn. The test for chlorophyll fluorescence parameters revealed that Fv/ Fm and Fv'/Fm'of M. yuyuanensis were 0.82 and 0.64, which were higher than those of M. maudiae and M.chapensis.5) Based on the systematical and comprehensive analysis, the three trees induced had the better adaptation on the photosynthesis and its compound storied forests had the greater ability to inhibit bacteria. Therefore, these trees can be induced to serve the urban forests in Nanjing.