Definition

1. Noun:
   • The central part of a plant ovule; contains the embryo sac: The nucellus is the tissue within the ovule of a seed plant that is surrounded by the integuments. It functions as the nutritive tissue for the developing embryo sac and, subsequently, the embryo.

Usage

• The is a botanical term used specifically in plant anatomy and reproduction. It is the core structure within an ovule where the megaspore mother cell undergoes meiosis to form the embryo sac.

Examples

• Noun:
  • The nucellus provides nourishment to the developing female gametophyte.
  • In some plants, the nucellus persists and becomes part of the seed, known as perisperm.

Advanced Usage

• "Degenerate nucellus": In many angiosperms, the is absorbed by the developing embryo sac and endosperm.
  • After fertilization, the nucellus often degenerates as the endosperm takes over its nutritive role.

Variants and Related Words

• Nucellar (adj): Pertaining to or derived from the nucellus.
  • The nucellar tissue was visible under the microscope.

Synonyms

• Megasporangium: In botanical terms, the ovule (which includes the nucellus, integuments, and embryo sac) is considered a megasporangium. The is the sporangium wall tissue.

Noun

1. central part of a plant ovule; contains the embryo sac