Question

Which of the following is WRONGLY paired?
1. Water of coconut : free nuclear endosperm
2. Kernel of coconut : cellular endosperm
3. Scutellum : embryo of coconut
4. Shell of coconut : fused pericarp and testa

Answer 1

Correct Answer - Option 3 : Scutellum : embryo of coconut

Concept:

• The endosperm is the food-laden tissue formed during the development of angiospermous seed which provides essential nutrients to the growing embryo and also to the young seedling at the time of seed germination. 
• In angiosperms, the endosperm develops from a triploid (3n) primary endosperm nucleus which is formed as a result of the fusion of a male gamete with the secondary nucleus of the central cell.
• Based on the first and subsequent divisions of the primary endosperm nucleus, the endosperm is of three types free nuclear, cellular, and helobial.

​Explanation:

• Free nuclear endosperm: In this type of endosperm development, the primary endosperm nucleus divides by repeated free nuclear divisions without the formation of walls.
• It results in the formation of a large number of free nuclei in the central cell of the embryosac. A big central vacuole develops in the embryosac pushing all the nuclei to the peripheral cytoplasm.
• The nuclear endosperm is the most common type of endosperm.
• Example: Water of coconut 
• Cellular endosperm: In the cellular type of endosperm development, the first nuclear division of the primary endosperm nucleus is followed by the formation of either a longitudinal or transverse cell wall in the central cell.
• Subsequent nuclear divisions and wall formations result in the formation of a cellular type of endosperm.
• Example: Kernel of coconut.
• Helobial endosperm: In this type of endosperm development, the primary endosperm nucleus moves to the chalazal end of the embryo sac. The first nuclear division is followed by the formation of a transverse wall resulting in the formation of a small chalazal cell and a large micropylar cell.
• Generally, the chalazal cell does not require further and functions as haustorium. The nucleus of the large micropylar cell divides by repeated free nuclear divisions and further development takes place in the same way as the nuclear endosperm. 
• Example: seen in monocots

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• Scutellum: It is the single cotyledon present in monocot plants. Eg. grasses.

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• The shell of coconut is formed by the fused pericarp and testa