Functions of Tapetum

Tapetum

A tapetum is the deepest layer of the anther, which encompasses the sporogenous tissue. The sporogenous tissue produces microspores that supply enzymes and nutrition for pollen development. Tapetum is mostly multinucleated due to mitotic cell division. Abnormal cell division can also lead to tapetum polyploidy.

The tapetum is a huge structure, and thus can absorb food and provide nutrition to the development of the pollen grains. They also aid the regulatory molecules that help in the formation of the pollen grains.

Tapetum

Structure of Tapetum

Tapetum is a thick single-celled nutritive layer found behind the epidermis and endodermis. Their cells are initially diploid in nature but can become polyploid due to abnormal cell division. Their primary role is to absorb nutrition from the middle layer, and provide it to the microsporocytes. Also, the tapetum cells can secrete enzymes and hormones. The tapetum layer is almost lost in the mature anther.

Also Read: Pollen Grains

Types of Tapetum

Secretory or Glandular Tapetum

They surround the anther locule. This type of secretory tapetum is more common in angiosperms.

Amoeboid or Plasmodial Tapetum

After the disintegration of the tapetal cell wall, a multinucleate structure, along with the cell protoplast called the plasmodium tapetum, is formed.

Refer: What are angiosperms?

Functions of Tapetum

  • Location – Found in between the anther wall and the sporogenous tissue.
  • Tapetum provides nutrition for the developing pollen grains.
  • They also act as a precursor source for the pollen wall or pollen coat.
  • It transports supplements to the anthers.
  • Pollenkitt is also formed by the tapetal cells around the microsporocytes. This pollenkitt is responsible for nutrition and pollen development.
  • The tapetal cells act as a precursor to sporopollenin. The outer wall of pollen grains contains a chemical called sporopollenin that protects the pollen from harsh external factors.
  • Tapetum expels Ubisch bodies, which helps thicken the pollen grain membrane. These ubisch bodies or orbicules are a part of the sporopollenin.
  • Also, it secretes the callase enzyme that breaks the callose compounds used to unite four pollens (pollen tetrad). Thus, they allow pollens from a tetrad to be separated.

Explore BYJU’S Biology for more interesting topics.

Frequently Asked Questions

How are pollen grains formed?

Pollen grains are male gametes that are found in the anther of flowering plants. The tapetal cells provide nutrition to the microsporocytes or the pollen mother cells. Later, these microsporocytes are differentiated through the meiosis process to produce microspores. The microspores are haploid structures that undergo mitosis to form pollen grains.

How do tapetal cells become multinucleate?

Tapetal cells are huge structures with many nuclei. These cells undergo mitotic division where cytokinesis does not occur. Only the nuclear cell membrane is divided, and thus it results in multi or polynucleate cells.

Also see: Pollination

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