What is Pollen?
In simple words, pollen can be defined as a fine or a coarse powder, which consists of microgemetophytes and produces the male gametes or the sperm cells. Palynology is the branch of Biology, which mainly deals with the study of pollens and their properties.
What are Pollen Grains?
Pollen grains are microscopic structures, which bear androecium – a male reproductive organ of a flower. The interior section of pollen grain contains cytoplasm along with the tube cell, which converts into a pollen tube and the generative cell releases the sperm nuclei.
Read More: Pollination
Structure of Pollen grains
Pollen grains are microscopic structures varying in their size and structure. The size of pollen grains generally varies with the species. Overall, the exact size of pollen grain ranges between three and two hundred micrometres or microns. The shape of the pollen grain is commonly found in round, ovule, triangular, disc or in a bean-shape with a smooth to spiky texture. The natural colour of pollen grains are white, which may also vary depending on the plant species. Some are yellow in colour, or orange, or cream and so on.
Pollen grains consist of three parts:
- The inside of the cell, which is filled with living cytoplasm, deteriorates rapidly during fossilisation.
- Intine, the inner layer of the cell wall comprises the cellulose and pectin. Similar to the cytoplasm, the intine also degrades rapidly during fossilisation.
- Exine, the outer layer of the cell wall, mainly consists of sporopollenin. It is one of the most resistant substances. It is an N-free polymeric substance belonging to the diverse class of organic compounds called terpenes.
Also Read: Fertilization in Plants