What is the Difference Between Integument and Testa?

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The main difference between integument and testa lies in their functions and structures. Integument is the outermost protective covering of an ovule, while testa is the outermost seed covering.

Some key differences between integument and testa include:

  • Function: Integument protects the ovule, while testa protects the developing embryo.
  • Pre-fertilization or post-fertilization: Integument is a pre-fertilization structure, whereas testa is a post-fertilization structure.
  • Nature of cells: Cells in the integument are living, thin, and smooth, while cells in the testa are non-living and thick.
  • Sclereids: Integument does not contain sclereids, while testa contains them.
  • Seed dormancy: Integument plays no role in seed dormancy, but the impermeability of testa to water can result in seed dormancy.
  • Origination: Integument arises from the chalazal ending of the ovule, while testa develops from the outer integument of the ovule once fertilization takes place.
  • Permeability: Integument is permeable to water, but testa is impermeable.

In summary, the integument and testa are protective coverings for the ovule and seed, respectively, and they differ in their functions, structures, and other properties.

Comparative Table: Integument vs Testa

Integument and testa are two outermost coverings in flowering plants, with the integument surrounding the ovule and the testa surrounding the seed. Here are the key differences between integument and testa:

Characteristic Integument Testa
Function Protects the ovule Protects the developing embryo
Origin Arises from the chalazal end of the ovule Derived from the outer integument of the ovule after fertilization
Thickness Thin, one or two layered Thick and one layered
Cell Type Living cells Dead cells
Sclereids Absent Present
Permeability Permeable to water Impermeable to water
Role in Seed Dormancy No role Plays a key role in seed dormancy

The integument is a thin, one or two-layered structure composed of living cells, while the testa is a thick, one-layered structure composed mainly of dead cells, including sclereids. The integument is a pre-fertilization structure that protects the ovule, while the testa is a post-fertilization structure that protects the developing embryo. The testa's impermeability to water plays a significant role in seed dormancy.