Vegetative anatomical characteristics and trichome morphology of the monotypic Martynia annua L. (Martyniaceae) for use in identification and crude drug search

Abstract

Background: Leaf epidermis and indumenta structure of M. annua were studied with the aid of microscopy for easy identification  of the plant materials when in fragments and for crude drug search. Stomata and trichome morphology appear significant in identifying the species. Paracytic and anomocytic stomatal types are basic but polocytic is additional on the abaxial surface of theepidermis.The overwhelming reports on the folkloric uses of Martynia annua L. (Martyniaceae) and the sole reliance on exo-morphology for its identification which gives room to error form the basis for this study. Moreso, the need to utilize as many data as possible for accurate identification of the plant is another important reason for its choice for investigation. Methods: A total of 20 plant samples were examined. 100 leaves and 40 stems, petioles and midribs obtained from both herbarium samples of the plant were examined. The epidermis was recovered after treatment with concentrated trioxonitrate (v) acid (HNO3) in capped specimen bottles for about 8–24hrs to macerate the mesophyll. Samples were stained with acidified phloroglucinol and then one drop of toluidine blue. They were mounted on glass slides and examined under the microscope (XSZ- 170BN Olympus) and photomicrographs were taken with microscope eyepiece camera (Toupview 3.7). Line drawings were made with camera lucida drawing instrument. Results: Interesting folia epidermal features were encountered. These include 3 stomatal types, two main types of trichomes namely: - Type 1: Long to short multicellular-glandular trichomes with globular heads and Type 2: Unicellular non-glandular globular-headed trichomes with stalk or no stalk. Conclusion: The report of leaf teeth in M. annua which is the begonioid type is novel and cell shape of the perivascular structures is oval to polyhedral.Asuite of these characters will aid identification of M. annua when a whole fresh plant specimen is absent.