PLANT DEVELOPMENT & REPRODUCTION - CBSE International

hilum represents the junction between ovule and funicle. Each ovule has one or two protectiveenvelopes called integuments. Integuments encircle the ovule except at the tip where a smallopening called the micropyle is organized. The chalaza is present opposite to the micropylarend. Chalaza is representing the basal part of the ovule. Enclosed, within the integuments, is amass of cells called the nucellus (Figure 28). Cells of the nucellus have abundant reserve foodmaterials. The embryo sac or female gametophyte is located in the nucellus. An ovule generallyhas a single embryo sac formed from a megaspore through reduction division.ChallazaNucellusIntigumentsAntipodal cellsCentral cellEmbroy sacEggs (Oosphere)MicropyleSecondary nucleousSynergidsVascular strandFiniculusFigure 28. Structure of an ovuleCan you think what was/is the significance of theseflagella in sperm cells?Unit 1 Plant Development & Reproduction 32