行道樹對臭氧之耐受性評

Assessment of Ozone Tolerance of Sidewalk Trees

本研究主要選取7種常見綠化樹種進行臭氧（O3）之耐受性評估，分別以「高濃度（200 - 800 ppb）、短時間（4 hr）」及「低濃度（60 ppb）、長時間（10 day）」進行熏氣試驗。結果顯示，當O3濃度調至60 ppb並熏氣10天作用後，大部分樹種Fv/Fm均低於0.75，除竹柏Fv/Fm值為0.79高於逆境標準0.75，顯示其餘樹種均遭受逆境。在高濃度試驗部分，大部分試驗樹種經濃度200 ppb的O3熏氣4小時後，其Fv/Fm值並無明顯降低，但以白水木降至0.71幅度最大；當O3濃度調至400 ppb時，白水木及欖仁顯示已遭受逆境，其餘樹種Fv/Fm值並無太大影響；當O3提升至800 ppb時，白水木已落葉無法測量，而欖仁Fv/Fm值則降低至0.61，由上述結果可得知當O3濃度提高，白水木及欖仁之Fv/Fm值也下降越多，而葉綠素濃度值均無明顯下降趨勢，而熏氣後與熏氣前Fv/Fm相對百分比所有測試樹種都在95%以上，顯示實驗濃度對供試樹種之葉綠素並無造成明顯急迫傷害。

In this paper, the effects of ozone pollutants on plants for their ozone tolerance were studied individually. Seven kinds of domestic common sidewalk trees were tested. Firstly, ozone fumigation experiments for plants were done at high ozone concentration (200~800 ppb), short exposure time (4 hr) and low ozone concentration (60 ppb), long exposure time (10 days), respectively, and chlorophyll fluorescence values (Fv/Fm) and chlorophyll concentration used to assess ozone tolerance of tree leaves were analyzed before and after fumigation tests. The results were shown that after the fumigation test at ozone concentration 60 ppb with exposure time 10 days, chlorophyll fluorescence values (Fv/Fm) for most tested trees except Decusscarpusnagi (Fv/Fm=0.79) were below 0.75 and this indicated that most trees suffered adversity. However, chlorophyll fluorescence values (Fv/Fm) for most tested trees except Messerschmidiaargentea (Fv/Fm=0.71) had no significant decrease after the fumigation test at ozone concentration 200 ppb with exposure time 4 hr. When ozone concentration increased to 400 ppb as above test, only Messerschmidiaargentea and Terminaliacatappa showed suffering adversity, and when ozone concentration increased to 800 ppb, the leaves of Messerschmidiaargentea had fallen out and chlorophyll fluorescence values (Fv/Fm) for Terminaliacatappa leaves decreased to 0.61. We conclude that Messerschmidiaargentea and Terminaliacatappa suffer a great deal from enhancing ozone concentration, but the effects of ozone concentration on chlorophyll concentration of all tested trees are insignificant.