Anatomical Study of Chenopodium ambrosioides L: Aromatic and medicinal plant wild-growing in Tunisia

Abstract

Anatomical studies of aromatic and medicinal plants are fundamental and play an essential role in taxonomy, phylogeny, and pharmacognosy particularly by the identification of structures that secrete bioactive molecules. In this context, the study of the structural anatomy of the stem, leaf, and root of Chenopodium ambrosioides L. (Amaranthaceae) wild-growing in Tunisia, revealed various important specific characteristics. A structural anomaly was identified by the presence of supernumerary cambiums; two in the stem and three in the roots. In stems, the first cambium, discontinuous and arc-shaped, is located near the periphery of the pith. While the second is situated in the outermost zone of the central cylinder. In the root, the first cambium is in an internal position, the second is functional towards the periphery, and the third is even further out and non-functional. Idioblasts are abundant in the parenchymatous tissues of aerial parts. Two types of trichomes have been identified; non-glandular and glandular. Non-glandular trichomes consist of a uniseriate multicellular stalk and an elongated apical cell. Glandular trichomes are of two types and are more abundant on the abaxial surface of the leaves. The first type consists of slender, elongated multicellular hairs featuring a short stalk and a small globoid apical cell that secretes essential oil. The second type is small, stout, and has a unicellular enlarged head. These microscopic characters could help with the authentication of this medicinal plant.