ANATOMY OF LEAVES IN POLYCYCLIC SHOOTS OF THE EUROPEAN BEECH (FAGUS-SYLVATICA)

The anatomical characters of European beech primary and secondary leaves (Fagus sylvatica L.) on polycyclic shoots obtained under various light conditions for 2 consecutive years were analyzed. Young plants were exposed to two luminosities, shade and light, which correspond to 20 and 80% of incident light, respectively. Shoots were grown under four light conditions during the 2 years: always in the shade, always in the light, in the shade during the 1st year and in the light during the 2nd year, and vice versa. The anatomical characters of leaves depend on both light intensity and cycle. Characters of secondary leaves vary more than those of primary leaves according to the light treatment. The effect of the luminosity applied during the 2nd year is more pronounced on secondary leaves. The cycle influence and the advantages brought by such a complex development are discussed.