Flowering Plant Life History – The Cartoon

The Life history of a Flowering Plant

Now we will look at the life history of a flowering plant. It is very similar to that of a fern except that there are male spores and female spores.

 

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Most of the plants around us are flowering.
Like ferns, the dominant part of the life cycle is the sporophyte.

 

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Flowering plants produce haploid spores. Microspores are produced within
the anthers whereas the megaspores are produced wthin the ovule.

 

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The microspores divide to produce the male gametophyte (pollen).

 

 

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The megaspore develops into a female gametophyte within the ovule.
The ovule is retained within the ovary.

 

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Within the female gametophyte an egg cell develops. You should be able to identify all
of the components of the pistil; if not a review of the previous section may help.

 

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Pollen is released and distributed by wind or other vector (bees, butterflies, etc).
Some may end up on the stigma of a receptive flower.

 

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The pollen germinates to produce a tube which digests its way through
the stigma and down the style.

 

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……the pollen tube grows, carrying nuclei toward the ovary.

 

 

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The pollen tube reaches the ovule.

 

 

 

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Once the pollen tube is in close proximity to the egg, two sperm
cells are released.

 

Screen Shot 2014-12-01 at 1.17.00 PMAn egg and sperm fuse to produce a zygote. the second sperm fuses
with other nuclei within the female gametophyte. This produces tissue
called endosperm.

 

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The zygote remains in the ovule within the ovary of the pistil.

 

 

Screen Shot 2014-12-01 at 1.18.17 PMThe zygote develops into the embryo. The ovule becomes the sees; the outer part of the ovule (integument) becomes the seed coat. Where would the endosperm be?

 

 

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The seed germinates and embryo develops into a new sporophyte.

 

 

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