Effects of ozone on the foliar histology of the mastic plant (Pistacia lentiscus L.)

Abstract

[EN] An open-top chamber study was conducted to investigate the tissue and cellular-level foliar effects of ozone (O-3) on a Mediterranean evergreen species, the mastic plant (Pistacia lentiscus L.). Plants were exposed at three different O-3 levels, and leaf samples were collected periodically from the beginning of the exposure. Although no visible foliar injury was evident, alterations of the plastids and vacuoles in the mesophyll were observed. Senescence processes were accelerated with an anomalous stacking of tannin vacuoles, and a reduction in the size and number of the chloroplasts. Overall, most of the modifications induced by O-3 were consistent with previously reported observations on deciduous broadleaf species, with the exception of alterations in the cells covering the secretory channels, reported here as a new finding. Comments on the feasibility of using microscopy to validate O-3 related field observations and subtle foliar injury are also given. (C) 2004 Elsevier Ltd. All rights reserved.