The_flower_and_the_angiosperm_lifecycle

The_flower_and_the_a - -The initial macrosporocyte(mother cell undergoes meiosis and produces 4 haploid daughter cells 3 of them degenerate and the

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Ioana Dobre The flower and the angiosperm lifecycle - the anther (tip of the stamen) produces pollen -stamen = anther + filament -stigma + style + ovary *not expected to know the different classifications but be aware of them e.g panicle, spike, raceme, corymb etc. . Immature anther cross section -Anther has 4 tubes that produce pollen - Tapetum - the layer surrounding the tubes that provides nutrition - A male flower can be sterilized by rendering the tapetum sterile this way self- pollination can be avoided - Mature pollen grains develop from the products of meiosis of microsporocytes (i.e. microspore mother cells) - Anther becomes mature and splits. The pollen grains can then be distributed by insects/wind Mature ovule with 8 nuclei in embryo sac
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Ioana Dobre The polar nuclei and the egg cell are important in the production of the seed.
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Unformatted text preview: -The initial macrosporocyte (mother cell) undergoes meiosis and produces 4 haploid daughter cells. 3 of them degenerate and the surviving one divides mitotically and produces 8 products: 3 antipodals, 2 synergids, and egg cell and 2 polar bodies -When the pollen grain lands on the stigma, it produces a pollen tube which goes down the style and grows through an opening called the micropyle germinates-2 sperm cells as well as a tube nucleus are sent down the pollen tube -The sperm nuclei are involved in fertilization, which occurs in 2 steps-A sperm nucleus + egg cell = zygote (2n)-one sperm nucleus + 2 polar bodies undergo triple fusion = endosperm (3n) provides nutrition to the embryo-this is known as double fertilization...
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This note was uploaded on 02/21/2012 for the course BIO Bio2137 taught by Professor Namroud during the Fall '11 term at University of Ottawa.

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The_flower_and_the_a - -The initial macrosporocyte(mother cell undergoes meiosis and produces 4 haploid daughter cells 3 of them degenerate and the

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