THE EFFECT OF WIND ON THE STRUCTURE AND BIOMECHANICS OF <i>CORYLUS COLURNA (BETULACEAE) </i>LEAVES
The effect of action on leaves anatomy, morphology and mechanics was examined in <i>Corylus colurna </i>trees from closed and open to wind sites. The leaves sampled at the open site had smaller lamina surface area and larger mass/area ratio as compared to these of leaves from the closed site. Anatomically the leaves from the windy site were thicker with denser palisade mesophyll. The petioles of the leaves from the open site were shorter and more tapered than ones from the closed site. At the cross section, the wind-exposed petioles had smaller lignified tissues fracture and larger collenchyma and parenchyma fractures compared with the wind-protected ones. As a result of these changes in morphology and anatomy, the wind-exposed leaves were less rigid mechanically. Another effect of wind on the leaves was the increase of absolute value of vascular tissues and hydraulic conductivity. The leaves from different sites demonstrated contrasted behavior in artificial air flow. The wind-exposed leaves curled into cone and bent downwind. The leaves from closed site bent at the middle of central vine. Probably the wind-induced change of leaves structure and biomechanics has adaptive character to minimize wind pressure load and save main functions at the same time. Some wind induced changes in the leaves structure differed from those in other species, which denote a number of adaptive mechanisms to wind and to several factors simultaneously.