Histological and Cytochemical Study of Embryogenesis stages in Zygophyllum fabago

The formation of the seed is part of the process of reproduction in seed plants. The study of the ontogeny of endosperm and embryogenesis was considered in current research using microscopic techniques. The samples were collected from different developmental stages. Then, the fixed samples were studied by different histochemical methods. The observations indicated that the ovule was of the anatropous and bitegmic type. The outer layers were removed in the early stages. Thus, the seeds of Z. fabago were categorized of testal type. During the early developmental stages, the endosperm was of nuclear type and then changed into the cellular type. This makes it easier for the embryo to connect with endosperm tissue in early stages. The endosperm develops gradually toward the central spaces and occupies the entire space of the embryo sac. In fact, the endosperm tissue remains until mature embryo stage and was not degenerated. Also globular, heart-shaped, torpedo-shaped and mature embryo stages along with the RAM, hypocotyl, and SAM were observed. Cytochemical tests indicated that in the later stage of seed development, the formation of starch grains and the strongly thickening of cell walls were occurred, causing considerable reduction of cell cavities as well as hardening of this tissue. In the other hand, the cell storage in the endosperm tissue was more lipid-based than proteinaceous compounds. But in mature embryo no carbohydrate was detected.