Summary: | In this study, four typical urban landscaping tree species were selected, three open top air chambers with different ozone concentrations were set, and the responses of chlorophyll fluorescence, chlorophyll content and relative conductivity of the trees to ozone stress were studied. The results showed that with the increase in ozone concentration, the maximum photochemical efficiency, electron transfer quantum yield, electron transfer rate (ETR) and chlorophyll content of the different tree species decreased significantly, while the relative conductivity of the different tree species increased significantly. Compared with the ozone concentration of NF, under an ozone concentration of nf40 and nf80, the decline in the rate of <i>F</i><sub>v</sub>/<i>F</i><sub>m</sub> of <i>Koelreuteria paniculata</i> and <i>Ginkgo biloba</i> was 2.47 and 2.28 times that of <i>Pinus bungeana</i> and <i>Platycladus orientalis,</i> respectively, and the increase in the rate of relative conductivity of <i>K. paniculata</i> and <i>G. biloba</i> was 2.11 and 1.28 times that of <i>P. bungeana</i> and <i>P. orientalis</i>, respectively. Under different ozone concentrations, the photochemical efficiency, electron transfer rate, chlorophyll content and relative conductivity of <i>P. bungeana</i> and <i>P. orientalis</i> were higher than those of <i>Ginkgo biloba</i> and <i>K. paniculata</i>, indicating that <i>K. paniculata</i> and <i>G. biloba</i> were more sensitive to ozone. This study is of great significance for improving urban environmental quality and ozone control and also provides a basis for selecting tree species with strong ozone tolerance.
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