G. Seed

A reproductive unit developed from afertilized, mature ovule

A seed consists of:

  • Seed coat

  • Embryo (with or without endosperm)

Seed Coat

  • Outermost covering
  • Testa: Outer layer
  • Tegmen: Inner layer

Hilum

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  • Scar on seed coat
  • Point through which seed attaches to fruit

Embryo and its Parts

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Embryonal Axis:

  • Consists of radicle and plumule

Epicotyl:

  • Part of embryonal axis between cotyledon and plumule

Hypocotyl:

  • Part between cotyledons and radicle

Cotyledons:

  • One or two present in embryo

Endosperm

  • Definition: Nutritive tissue formed in seed

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Types:

Endospermic Seed

  • Food is partially used up

  • Example: Castor

Non-endospermic Seed

  • Food is completely used up

  • Example: Pea