Ch. 38 Flowering Plant Reproduction

Ch. 38Flowering Plant Reproduction

• I.            Alternation of generations• A. Dominant sporophyte• B.  Gametophyte lives on sporophyte, and is actually the

flower.• 1. Male portion is the stamen- the anther has the pollen• 2. The female portion is the _carpel, the stigma is where the

pollen lands• 3. Complete flowers have both male and female parts and are

also called perfect flowers• 4. Incomplete flowers lack  one ore more of the organs floral

parts like grasses lack petals.• 5. A imperfect flower is missing the stamen or carpel.• 6. Microspores are male• 7. Macrospores are female

• II.         Fertilization• A. Prevention of self-fertilization• 1.  Some plants are self-incompatible therefore they need to be

fertilized by another’s sperm.• 2. Self-fertilization• B.  Double Fertilization• 1. The pollen which lands on the stigma divides forming 2 nuclei.• 2. A tube grows from the pollen down the style to the ovary.• 3. One sperm fertilizes the egg• 4. The other sperm fertilizes 2 nuclei in the ovary creating a triploid

cell which will grow into the endosperm.• 5. The egg becomes the zygote while the endosperm provides food

when it is germinated.

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• C.  The seed• 1. Hypocotyl-embryonic axis• 2. Radicle- embryonic root• D.  The fruit• 1. The cereal you eat with milk is actually a fruit not a

 dry seed.• 2. Seeds can stay dormant for long periods of time.• 3. Imbibition-absorption of water which activates seed

germination

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Botanists call the strawberry a "false fruit," a pseudocarp. A strawberry is actually a multiple fruit which consists of

many tiny individual fruits embedded in a fleshy receptacle. The brownish or whitish specks, which are commonly considered seeds, are the true fruits, called

achenes, and each of them surrounds a tiny seed.

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• III.      Asexual Reproduction• A. Plants can clone

themselves by vegatative reproduction. (runners in strawberries)

• B.  Fragmentation-separation of parent plant into parts that can form new plants