Impact Of Surface Ozone Pollution On Leaf Organizational Structure Of Tree Leaves

Surface ozone pollution, which puts damage not only to air quality but also to leaf tissue structure and growth of plants, is recently more and more serious due to the influence of human activities. Three methods including open top chamber （OTC）, Assessment of Ozone Injury in the fields and paraffin section were applied in this study to determine the ozone injury symptoms of subtropical common tree species Characteristics of ozone injury of leaves were observed using optical microscopy technique. The thickness of palisade tissue, spongy parenchyma, upper epidermis, lower epidermis and the whole leaf were measured by LAS V4.5, the ratio of palisade tissue to spongy parenchyma was further computed.After analyzing these data by SPSS 19.0 the results show that: ①the plant after the ozone damage the blade show visible symptoms and symptoms change trend of the following:most of the phenomena of plant leaves have faded green, tip gradually in diffusion, and is just occasional spots or patches between the fine veins, brown, yellow, black spots, patch. slight phenomena on the back of leaf, showed no damage symptoms on veins.②he internal structure of leaves have changed significantly although there are no visible injury symptoms, symptomatic and asymptomatic leaf tissue structure of each species differs significantly,③alisade tissue thickness and spongy tissue thickness show consistent variation trend. No damage exists in vascular tissue for symptomatic and asymptomatic leaves.④5 species possess raised ratios of palisade tissue to spongy parenchyma for symptomatic and asymptomatic leaves while 13 species hold decreased and stable ratios.⑤In indoor O₃ fumigation fumigation, Phoebe Chekiangensis leaves the standard air and local air treated asymptomatic leaf structure are compared, palisade tissue, spongy tissue, leaf, epidermis thickness increased significantly, respectively, an increase of 37.57% and 14.29%,9.44%,22.42%, thickness of upper epidermis significantly reduces the 58.23%; local air treatment of symptomatic and asymptomatic leaf palisade tissue and spongy tissue, leaf thickness were significantly increased, respectively, an increase of 7.97, 25.02%, and lower epidermis did not change significantly.45nmol·mol-1 O₃ concentration and local air, no symptoms of leaf palisade tissue tissue compared ratio increased, but in local air treatment leaves asymptomatic palisade tissue tissue ratio decreased.