What are called ovules?
Ovules are the structures within the ovaries of flowering plants that develop into seeds after fertilization. They contain the female gametophyte (also called the embryo sac in angiosperms), which houses the egg cell. The ovule itself is composed of a nucellus (food tissue), protected by integuments (precursors to the seed coat). After successful pollination and fertilization by a pollen grain, the ovule matures into a seed, containing the embryo.
- Formation: Ovules form within the ovary of a flower.
- Structure: They consist of a central nucellus surrounded by one or two integuments. The nucellus provides nourishment to the developing embryo.
- Fertilization: A pollen tube carries a male gamete to the ovule where it fertilizes the egg cell within the embryo sac.
- Seed Development: Following fertilization, the ovule develops into a seed, with the integuments becoming the seed coat and the fertilized egg developing into the embryo. The nucellus may also contribute to the endosperm, providing nutrients for the embryo.
- Gymnosperms vs. Angiosperms: In gymnosperms (like conifers), ovules are exposed, while in angiosperms (flowering plants), they are enclosed within the ovary.
The Role of Ovules in Plant Reproduction
Ovules are essential for plant reproduction. They are the female reproductive structures that contain the egg cell necessary for the creation of seeds and ultimately, new plants. Without ovules, sexual reproduction in plants would not be possible. The process of fertilization, where the male gamete fuses with the egg cell within the ovule, is crucial for the formation of a zygote and subsequent development of an embryo. This intricate process ensures the continuation of plant species.
