Epidermal Structure and Ontogeny of Stomata in Vegetative and Reproductive Organs of Ephedra and Gnetum

Abstract

The epidermal structure and development of stomata in vegetative and reproductive organs of Ephedra foliata and Gnetum ula is described. The epidermal cells are polygonal, isodiametric, or elongated with thick or thin straight, arched, or slightly sinuous anticlinal walls. The cuticle is thin or thick. Papilla-like unicellular outgrowths are present in Ephedra foliata. The mature stomata are orientated parallel to the longitudinal axes or irregularly. The mature stomata are anomocytic, paracytic, with a single subsidiary cell, cyclocytic, and actinocytic. Arrested development, contiguous stomata, and stomata with aborted guard cells have been observed. The ontogeny of stomata on different organs of these two plants is typically haplocheilic or perigenous but the stomatal apparatus varies from organ to organ.