Class 12th Biology 2011 Set3 Delhi Board Paper Solution
Question 22
Draw a diagram of a male gametophyte of an angiosperm. Label any four parts. Why is sporopollenin considered the most resistant organic material?
Answer
Spherical pollen grains measure about 25-50micrometer in diameter, with duel layer of cell for its protection. Outer layer is called as exine made up of sporopollenin which is resistant to higher degree of temperature, organic materials, acids and alkali. Till now no enzyme is reported that can digest sporopollenin and it is so hard that many fossils are found fresh because of sporopollenin.
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