Photosynthetic Inhibition in Leaves of Ailanthus altissima under O3Fumigation

Abstract

We investigated the enect of <TEX>$O_3$</TEX> on the photosynthetic characteristics of tree of heaven (Ailanthus altissima) that is naturalized plant and used as restoration plant for contaminated area. Two-year-old seedlings were planted to pots and transferred into closed <TEX>$O_3$</TEX> chamber. Photosynthetic pigments contents and photosynthetic characteristics were measured every three weeks under 100 pub <TEX>$O_3$</TEX> fumigation. There was no visible foliar injury by <TEX>$O_3$</TEX> exposure and contents of photosynthetic pigments did not show significant differences between control and <TEX>$O_3$</TEX>-treated seedlings. Also there were no significant differences in stomatal conductance, and water use efficiency. But photosynthetic rate and apparent quantum yield (AQY) of <TEX>$O_3$</TEX> treated seedlings were reduced after nine weeks of ozone fumigation. In addition, the reduction of carboxylation efficiency and photorespiration were observed in the leave of <TEX>$O_3$</TEX> treated seedlings after six weeks. In accordance with our result, carbon fixation system of A. altissima was most sensitive to <TEX>$O_3$</TEX> stress to evaluate physiological damage induced by <TEX>$O_3$</TEX>.