Epicuticular wax on stomata of damaged silver fir trees [Abies alba Mill.]

Condition of epistomatal wax on the abaxial surface of the current and previous-year needles of damaged silver fir trees (Abies alba Mill.), both from the polluted Risnjak and "clean" Donja Dobra sites in Gorski Kotar region, both influenced by pollutants coming from Europe, during two years, three times a year, were examined with Scanning Electron Microscope. In the course of time the wax tubules on the epistomatal rims of stomata in polluted, but also in "clean" needles surface, become fused and agglomerated rapidly to various extents of morphologically different types of amorphous wax crusts, primarily compact and particulate ones. This process begins very early, especially in polluted Risnjak site, and may be interpreted as a possible result of air pollution. However, the recrystalization, or production of new tubules, also appears relatively quickly in mostly cases. Quantitative estimations indicate a very large total amount of amorphous wax crusts in the current-year needles, and a very high percentage of the same wax in previous-year needles. Amorphous wax crusts cover stomatal pores, as well as the rims, disturbing the normal gas exchange. Statistically there is a signicant tendency of increase in wax degradation in the needles of the polluted site in comparison with those of the unpolluted one, but there is an insignificant wax degradation among the needles of damaged trees within each site. These results confirmed most of the research done in our preliminary report

Comparative morphology of some species of genus Arum from Eastern Slavonia and Baranya region in Croatia

Comparative variability in some morphological properties, for example, in leaves and flowers, among and within each of three species Arum italicum Mill., Arum maculatum L. var. maculatum and var. immaculatum Reichb. as well as Arum alpinum Schott et Kotschy var. pannonicum Terpó and var. intermedium Terpó from three localities in Eastern Slavonia and from two in Baranya region in Croatia were studied. The investigation included the variability among and within of the populations and habitats and among the species. The results obtained indicated significant differences chiefly in some morphological parameters, such as in length of petiole and peduncle, in length of spathe, in length and diameter of spathe-tube, in length and diameter of appendix as well as in length of pistillate and staminate flowers. Moreover, the taxonomic treatment of the species Arum alpinum Schott et Kotschy as a disagreement was also discussed. The most of the morphological features are in the concordance with observations made by Prof. Bedalov