Which of the following statements about sporopollenin is incorrect?

It forms the intine layer of pollen grains.

The correct answer is Option (3) → It forms the intine layer of pollen grains.

Pollen grains are generally spherical measuring about 25-50 micrometers in diameter. It has a prominent two-layered wall. The hard outer layer called the exine is made up of sporopollenin which is one of the most resistant organic material known. It can withstand high temperatures and strong acids and alkali. The inner wall of the pollen grain is called the intine. It is a thin and continuous layer made up of cellulose and pectin.

Sporopollenin is considered the hardest substance in the plant kingdom. It is a highly durable and resistant material that makes up the outer layer of pollen grains and spores. Sporopollenin is known for its exceptional stability and resistance to various environmental conditions. It can withstand strong acids, high temperatures, enzymes, and other degrading agents, making it highly durable and long-lasting.

Due to its robust nature, sporopollenin helps protect the genetic material inside pollen grains and spores during dispersal and ensures their successful reproduction. Pollen grains are well-preserved as fossils because of the presence of sporopollenin. Therefore, sporopollenin is the hardest substance in the plant kingdom.