Image analysis of the stomatal cell walls of Picea abies (L.) Karst. in pure and ozone-enriched air

 The method of image analysis was used to re-investigate previously described structural changes in spruce needles following their exposure to ozone. The changes observed in fumigation experiments were compared with the modifications observed at a site with a similar ozone load. Use was made in each case of needles for which the varying behavioural patterns were known from physiological experiments. In samples with reduced ability to regulate stomatal aperture, the cell walls of the stomatal apparatus showed a reduction in absorptive power at 280 nm. This was interpreted to be a result of delignification of the cell walls in question due to the direct impact of ozone on the surface of the needle. Received: 21 May 1997 / Accepted: 30 June 1997