Preliminary report on epicuticular wax surface condition on stomata of Abies alba Mill. needles from Risnjak National Park in Croatia

The structure of epicuticular wax on the stomata surface in both very young and one-year-old fir needles from Risnjak National Park in Croatia were ex amined with a scanning electron microscope. The stomata surface is first covered with wax crystalloids in the form of r odlets. In the course of time the rodlets become fused and agglomerated int o amorphous wax crusts; this process begins very early. In addition to wax crystalloid quantitative estimation indicates a relative ly large total amount of amorphous wax in very young needles (similar to 20 days) and a very high percentage of amorphous wax crusts in one-year-old n eedles. Wax crusts cover stomatal pores in addition to the rims, making nor mal gas exchange impossible. The early start of wax degradation may be inte rpreted as a possible result of air pollution.