Leaf Epidermal Features of Ailanthus altissima (Mill.) Swingle in Different Development Stages

The leaf epidermal features of Ailanthus altissima (Mill.) Swingle,including epidermal hairs, stomatal apparatus, cuticles and glands, were examined at different development stages (leaf bud, young, near-mature and mature leaf) under light microscopy (LM) and scanning electron microscopy (SEM). We observed two kinds of epidermal hairs on both sides of the leaf, that is, single-celled non-glandular hairs and capitate glandular hairs. Hair densities were greatest in the leaf bud, then decreased gradually with leaf development. The stomatal apparatus was mostly found on the lower leaf epidermis, and stomatal density was greatest in the near-mature leaf. The leaf epidermis was covered with striated cuticles, which showed maximum swelling degree in the near-mature leaf. Leaves had serrated protuberances on the leaf basal part. Each protuberance had one gland, which produced transparent mucus when mature. The epidermal features of A. altissima leaves reflect their adaptation to environments during long-term evolution.