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Flower Structure

Flower Structure. A plant can be divided into 3 parts:. Some plants also produce flowers!. Flowers. Reproductive organs of some plants There are many adaptive advantages to reproducing with flowers, such as seed protection & dispersal!. Anatomy of a Flower: Male Structures.

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Flower Structure

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  1. Flower Structure

  2. A plant can be divided into 3 parts:

  3. Some plants also produce flowers!

  4. Flowers • Reproductive organs of some plants • There are many adaptive advantages to reproducing with flowers, such as seed protection & dispersal!

  5. Anatomy of a Flower:Male Structures • Stamen: male reproductive organs of a plant, contains the anther & filament • Anther: tip of a flower’s stamen, it contains the pollen • Filament: part of the male reproductive organ that holds the anther

  6. Anatomy of a Flower:Male Structures These are stamens of a Hippeastrum with white filaments and prominent anthers carrying pollen.

  7. Anatomy of a Flower:Female Structures • Carpel (pistil): includes the ovary, style, & stigma • Stigma: uppermost part of the carpel, receives the male pollen during pollination • Style: long tube on top of the ovary & below the stigma • Ovary: produces ovules, found at the base of the carpel

  8. Anatomy of a Flower:Female Structures Carpel of an Orange Day Lily The pollen grains travel through the style to the ovary where fertilization occurs.

  9. Anatomy of a Flower:External Structures • Petal: attract insects & pollinators • Often brightly colored & come in many shapes • Sepal: small leaves located directly under a flower • Peduncle: stalk or stem that supports the flower

  10. Bee pollinating a peach tree flower – notice the pollen stuck to the bee’s legs!

  11. Male Structures • Female Structures • Neither • Both Male! These are stamen with white filaments & large anthers carrying pollen.

  12. Male Structures • Female Structures • Neither • Both Female! This is the carpel, which leads down to the ovary.

  13. Male Structures • Female Structures • Neither • Both Both! You can see the stamen & the carpel.

  14. If flowers can have male & female parts, can they self-pollinate? Yes! • Flowers can self-pollinate OR cross-pollinate. How do plants reproduce?

  15. Plant Reproduction

  16. Alternation of Generations • Plants have 2 life cycles: • Diploid (2n) sporophyte generation • Haploid (1n) gametophyte generation

  17. Sporophyte & Gametophyte Generation • Our human bodies undergo meiosis to create gametes. Once an egg is fertilized, it undergoes mitosis for the baby to grow & develop. • Plants undergo haploid gametophyte generation to create gametes. Once fertilization occurs, the plant switches to diploid sporophyte generation to grow.

  18. Diploid (2n) Sporophyte Generation • Familiar, recognizable form of a plant • Develops from a zygote • Cell replication through mitosis

  19. Haploid (1n) Gametophyte Generation • Pollen & ovules are gametophytes (gamete cells) created from meiosis. • Carry sperm & egg cells • Combine to form a zygote, which grows into the sporophyte generation

  20. Alternation of Generations The actual plant that you think of is the sporophyte (2n). The sporophyte undergoes meiosis to produce the gametophyte (1n). The male gametophyte is pollen & the female gametophyte is the ovule. The gametophytes (pollen & ovule) produce gametes (sperm & egg). When gametes fuse, a new sporophyte will develop.

  21. Gametophytes • Gymnosperms: cones • Pollen forms in the male pollen cones. • Ovules form in the female seed cones. • Angiosperms: flowering plants • Flower is the reproductive structure, with male (stamen) & female (carpel) parts

  22. Is pollen a gametophyte or sporophyte structure? • Gametophyte • Sporophyte • Neither • Both Gametophyte (1n) & carries sperm cells

  23. Pollination • Process in which pollen is spread • Plants can be self-pollinated or cross-pollinated • Wind, insects, & animals can all help pollinate The flower of an angiosperm helps attract birds & insects!

  24. Double Fertilization • 2 fertilizations occur in angiosperms (flowering plants): • 1 sperm nuclei fuses with an ovule to produce a diploid zygote (plant embryo). • A second sperm nuclei fuses with 2 polar nuclei (formed from meiosis in the ovary) to produce the endosperm.

  25. Double Fertilization • 1st fertilization: 1 sperm nucleus combines with 1 egg nucleus = zygote (now 2n) • 2nd fertilization: 2 ovules have joined together in the ovary (making them diploid) • A second sperm nucleus will fuse with these (making it triploid, or 3n) • This becomes the endosperm.

  26. Anatomy of a Seed • Endosperm: food source for the plant embryo • Cotyledon: seed leaf of plant embryo (will become the first leaves) • Seed Coat: protection

  27. Which of the following does not play a direct role in sexual reproduction? • Petal • Ovary • Anther • Style Petals!

  28. What is the function of the endosperm in a fertilized ovule? • Protect the seed from high temperatures. • Become the leaves of the plant. • Provide a food source for the seed. • Protect the seed from drought. Food Source!

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