STRUCTURAL ORGANISTION OF PLANTS AND ANIMALS
ANATOMY OF FLOWERING PLANTS
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Question
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Detailed explanation-1: -Assertion: A typical angiosperm embryo sac is 8 nucleate and 7 celled. Reason: The large central cell of embryo sac has three polar nuclei.
Detailed explanation-2: -gametophyte of angiosperms (called the embryo sac) is tiny and contains only a few (typically eight) nuclei; the cytoplasm associated more or less directly with these nuclei is not partitioned by cell walls.
Detailed explanation-3: -A mature embryo sac consists of two synergids, one egg cell and three antipodal cells with one nucleus each. Then there is one large central cell that has two nuclei. Hence, a mature embryo sac consists of 7 cells and 8 nuclei.
Detailed explanation-4: -Three cells present at the chalazal end of embryo sac are called as antipodals. The large central cell has two polar nuclei. This makes embryo sac 7 celled and 8 nucleate structure.
Detailed explanation-5: -Thus, a typical angiosperm embryo sac at maturity is 7-celled but 8-nucleated as the central cell has 2-nuclei.