Question

Where is sporopollenin present in plants? States its significance with references to its chemical nature.

Answer 1

Hint: Sporopollenin is one of the foremost chemically inert biological polymers. It is the main component of the outer walls of the plant spores and pollen grains. It is chemically very stable and is typically well retained in soils and deposits.

Complete answer:
Sporopollenin may be a biological polymer that's composed of carbon, hydrogen, and oxygen. It's one among the foremost extraordinarily resistant materials known within the organic world. Sporopollenin is present within the exine of pollen grains in plants.
The chemical importance of sporopollenin is as follows: Sporopollenin, the material of the exine has been defined as supporting the chemical characteristic of being "the resistant non-soluble material left after acetolysis.
The carbon-hydrogen ratio is 5:8mol: mol. It's a mixed copolymer with an aliphatic core.
Some more chemical significance of sporopollenin:
> Sporopollenin is very chemical resistant.
> It is derived from lipids and carotenoids.
> No effect of enzyme, alkali, and acid
> This sporopollenin helps the pollen grain to be preserved.
In 2019 research at MIT determined via thioacidolysis degradation and solid-state NMR the molecular structure of pine sporopollenin, finding it primarily composed of polyvinyl alcohol units alongside other aliphatic monomers, all crosslinked through a series of acetal linkages. Microscopy shows that the entire cells that surround the developing pollen grain within the other have a lively secretory system containing lipophilic globules. These globules are believed to contain sporopollenin precursors.
Chemical inhibitors of pollen development and lots of sterile mutants have effects on the secretion of those globules by the tapetal cells.

Note: The algae (chlorophyte) is probably liable for the event of sporopollenin and it's an introduction into the arrangement of upper green plants, where it's principal function is protection against oxidation and desiccation.