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What is the Perisperm?

Published in Plant Seed Anatomy 2 mins read

The perisperm is a nutritive tissue found in some seeds, distinct from the more common endosperm. It plays a crucial role in nourishing the developing embryo.

Understanding the Perisperm

The perisperm is essentially a mass of nutritive material located *outside* the embryo sac. This contrasts with the endosperm, which develops within the embryo sac itself.

Here’s a closer look:

  • Origin: The perisperm is derived from the nucellus, which is the tissue surrounding the megagametophyte (the embryo sac) in the ovule.
  • Function: Its main purpose is to provide nutrients to the developing embryo, acting as a food reserve. This is especially important in seeds where the endosperm is limited or absent.

Perisperm vs Endosperm

Feature Perisperm Endosperm
Origin From the nucellus From the fusion of polar nuclei and sperm
Location Outside the embryo sac Inside the embryo sac
Function Nutritive tissue for the embryo Nutritive tissue for the embryo
Presence In some flowering plants In most flowering plants

Characteristics

  • Nutrient-Rich: The perisperm contains stored food reserves, typically in the form of starch, oils, or proteins, which are used by the seedling during germination.
  • Persistent Tissue: It is a persistent tissue, meaning it remains in the mature seed, unlike some other tissues that may be absorbed during seed development.
  • Location in Seed: It surrounds the embryo, providing it with immediate access to nutrients.

Examples

Seeds with well-developed perisperm include:

  • Black pepper
  • Beets
  • Coffee

Conclusion

The perisperm is a vital component in the seeds of certain flowering plants, supplementing or replacing the endosperm as a primary nutritive tissue. It’s derived from the nucellus and plays a critical role in early embryo development and seedling establishment.