Stomata Polymorphism in Leaves of Apple Trees (Malus domestica Borkh.) Growing under Mountain and Plain Conditions

Abstract

Stomata polymorphism in leaves of apple trees (Malus domestica) growing under mountain and plain conditions has been studied using scanning electron microscopy. The leaves of this species were hypostomatic with anomocytic stomata and radially diverging cuticular folds combined into bundles (cuticular bundles), the number of which usually corresponded to the number of epidermal cells surrounding the stomata. The average size of stomata increased linearly as the number of cuticular bundles increased. Under favorable conditions (600-m altitude above sea level), a high density of rounded stomata was observed. Stress conditions, such as high temperatures and droughts on the plain (300-m altitude) or high insolation and temperature drops in the mountains (1200-m altitude), provided the same effect on the micromorphology of the leaf surface, while the effect of altitude was manifested in the reduction of the size of epidermal cells.