Study on the reproductive organs development and embryological features of Agrimonia eupatoria L. (Rosaceae)

Abstract

ABSTRACT Agrimonia eupatoria L. (Rosaceae) as a valuable plant has been included in the International Union for Conservation of Nature (IUCN) Red List of threatened medicinal plants in some parts of the world. Because information on the development of reproductive organs is important to identify the species characteristics, in this study, the structure of stamen and gynoecium, developmental stages of the anther, ovule, male and female gametophyte, and embryo development in Agrimonia eupatoria were investigated using light and scanning electron microscopy. The results showed that the primary anther wall includes an epidermis, an endothecium, two or three rows of middle layer, and a glandular tapetum. The microspore tetrads are tetrahedral. Some of the tapetal cells are binucleated and mature pollen grains are two-celled. The pollen dispersal unit is the monad. Pollen grains are tricolporate, with striate exine. The ovules are hemi-anatropous, pendulous, unitegmic, and crassinucellate. Hypostase, funicular obturator, and nucellar cap were observed in the ovules. The functional megaspore in the linear megaspore tetrad is located in the micropylar zone. The development of the embryo sac was of Polygonum-type. The embryogenesis includes globular, transition, heart-shaped, and torpedo phases. Embryogeny of this plant is of the Asterad type. Haustorium endosperm was observed in the embryo sac.