Describe the development of endosperm in angiosperms. Differentiate between the embryo of a dicot and that of a grass, with labelled diagrams.

1. 1 · Define endosperm in one line. Endosperm is the triploid, food-storing tissue that develops from the primary endosperm cell after triple fusion.
2. 2 · Free-nuclear stage. The PEN divides repeatedly without cell walls, giving free-nuclear endosperm; tender coconut water is an example.
3. 3 · Cellular stage and fate. Walls form later; the white coconut kernel is cellular endosperm. It is used up in pea, groundnut and beans, but persists in castor and coconut.
4. 4 · Compare the embryos.
   • Dicot: two cotyledons; epicotyl with plumule; hypocotyl with radicle and root cap.
   • Grass: one cotyledon, the scutellum, on one side; coleoptile over the shoot apex; coleorrhiza over the radicle and root cap.
5. 5 · Draw both embryos. [Diagrams: typical dicot embryo and L.S. of a grass embryo, labelled]
6. 6 · Close in one line. So the endosperm feeds the embryo, and the structure of the embryo differs between dicots and monocots.

Scoring tip: Name the coconut as the example of free-nuclear endosperm; it is the answer examiners expect.