What does EXINE mean?

Here is the requested information on "exine": 1. Parts of Speech: Noun 2. Definitions: - The tough outer layer of a pollen grain or spore, composed of a complex organic substance called sporopollenin. 3. Pronunciations: - US: /ˈɛksɪn/ - UK: /ˈɛksɪn/ 4. Origin and Usage: - The word "exine" comes from the Greek word "exinos," which means "outer." It was first used in the early 20th century to describe the outer layer of pollen grains and spores. - Exine is an important part of the reproductive process in plants, as it protects the genetic material inside the pollen or spore from damage during transport and fertilization. 5. Synonyms: - None 6. Related Words: - Spore, pollen, grain, layer, outer 7. Example Sentences: - The exine of the pollen grain is responsible for protecting the genetic material during fertilization. - The thick exine layer on the spores allows them to survive harsh environmental conditions. - Scientists are studying the chemical composition of exine to better understand its properties and potential applications.