Comparative anatomy of flowering and sterile shoot leaf of Hedera helix L. (Araliaceae)

Abstract

Hedera helix L. is a medicinal plant and belongs to the Araliaceae family. Flowering shoots of the plant have elliptic-cordate and sterile shoots have palmately lobed leaves. Plant material was collected from Hacıkadın valley (Ankara-Turkey). The anatomical features of leaf and petiole were examined comparatively in this study. The results showed that both leaf types were dorsiventral. Single layer epidermis is covered by thick cuticle. The palisade parenchyma cell is oval-shaped in the flowering shoot mesophyll, also is elongated in the sterile shoots. In both leaf types, stomata are located in the lower epidermis. Flowering shoot leaf is covered with tufted hairs, sterile shoot leaf stellate hairs. The midrib of the leaves have a similar structure. Collenchyma tissue is located underside the upper and lower epidermal layers in the midrib. The vascular bundles are arc-form and tends to a ring-form. The sclerenchymatous tissue surrounds the vascular bundles and secretory canals are located in the adaxial side of the bundles. The leaves contain abundant druse crystals and starch grains. Petiole anatomy is similar in both leaf types. Unlike leaves, petioles are covered with stellate hairs, do not contain tufted-type. The collenchymatous tissue is located bottom the epidermal layer. The vascular bundles are embedded in the parenchymatous tissue and secretory canals are located on the adaxial side of petiole. Both petioles contain numerous druse crystals and starch grains.