Effects of Ozone and Drought on Physiological Characteristics of Three Seedling Types in South China

Abstract

Seedlings of Michelia macclurei, Cinnamomum camphora and Rhodoleiachampionii were placed in open-top chambers (OTC) with two ozonic treatments including E40 (nature air, 40 ppb) and E150 (150 ppb) and two water treatments. Physiological indexes such as chlorophyll, soluble sugar, soluble protein, proline, MDA and SOD of three seedling types were evaluated. With increasing experimental time, chlorophyll content generally decreased or remained steady, soluble sugar content increased followed by a decrease and SOD activity increased for the three seedling types in ozone treatment, drought treatment or ozone-drought intercross treatment. Contents of soluble protein and proline increased for the three seedling types in ozone treatment and drought treatment. The MDA content increased for M. macclurei and C. camphora in ozone treatment and drought treatment and for R. championii in the three stress treatments. Principal component analysis indicated that the resistance abilities of ozone, drought or intercross stress for the three seedling types was C. camphora seedlings > M. macclurei seedlings > R. championii seedlings.