Tapetum: It is the anther’s innermost cell layer surrounding developing pollen mother cells and/or microspores, supplying nutrition and enzymes needed for microsporogenesis and pollen maturation. Two separate sexes engage in sexual reproduction in plants. Gametes are the blooming plant’s reproductive cells. The flower reproduces sexually since there are both male and female gametes. The male gamete pollen grains develop in the anther and pollen sac in which pollen grains are generated. The epidermis, endothecium, middle layer, and tapetum are the four layers that surround each pollen sac.

Structure of Tapetum

• It 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.
• These cells can secrete enzymes and hormones.
• Layer is almost lost in the mature anther.

Types of Tapetum

• Secretory Tapetum: It is also known as the Glandular. This type of anther remains surrounded by the anther locule.
• Amoeboid Tapetum: It is also known as Plasmodial. In this type, a multinucleate plasmodium is formed after the dissolution of the tapetal cell walls.

Function of Tapetum

• It 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.
• These 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.
• It 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.

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By Team Learning Mantras