The study of structural and developmental characters of pollen grain, ovule and seed in Ebenus stellata Boiss.

Structural and developmental characters of reproductive organs and seed in Ebenus stellata Boiss., which is the only species of Ebenus L. in Iran, were investigated for the first time using bright field, polarizing and fluorescence microscopy with different staining techniques. In this plant, the ovary has one carpel, one ovule, dense long villosus with papillose and no peduncle. The ovule is anatropous, crassinucellar, bitegumic and has endothelium. Meiosis of megasporocyte results in a T-shaped tetrad and then chalazal megaspore develops into an embryo sac with the pattern of Polygonum type. The polar nuclei are close to the egg apparatus and even after egg fertilization remain separate from each other. In embryo sac of this plant specialized tissues like hypostase, postament and a cup-like operculum are formed. In seed, a layer of macrosclereid radial cells, double palisade layer and a tracheid bar which is surrounded by parenchymal cells that contain phenolic compounds, are present. In female gametophyte, the anthers are tetrasporangiate and its wall development follows the dicotyledonous type, consists of four layers: epidermis, endothecium, one middle layer and uni-nucleate secretory tapetum. Microspores development is simultaneous in sporangiates of an anther and arrangement of microspores is mostly tetrahedral in callosic wall. Fibrous thickenings are developed in the endothecium when shed. Mature pollen grains are ellipsoidal, tricolpate and two-celled.