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Plant Reproduction.

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Presentation on theme: "Plant Reproduction."— Presentation transcript:

1 Plant Reproduction

2 Angiosperms (flowering plants)
Plants that protect their seeds within the body of a fruit. Make up ¾’s of all plants, including: Trees, shrubs, herbs, grasses, water plants…

3 Structure of a Flower 1. Pistil 2. Stigma 3. Style 4. Ovary 5. Stamen
6. Filament 7. Anther 8. Petal 9. Sepal 10. Receptacle 11. Stem

4 Male Reproductive Structure
The stamen consists of two parts: Anther and Filament The anther is where meiosis occurs to produce haploid pollen The filament is a stalk that supports the anther

5 Female Reproductive Structure
The pistil consists of the stigma, style and ovary The sticky stigma receives the pollen from the anther The pollen grows a tube down through the style Meiosis occurs in the ovary to produce haploid ovules

6 Reproductive Structures
Petals: colourful structures that attract pollinators. Sepals: surround and protect the flower bud.

7 Pollination Wind, insects or other animals transfer pollen from the anther of one flower to the stigma of another Flowers vary depending on pollination mechanism

8 Pollination Animation

9 Pollination Vectors Wind Pollination: Dull, scentless
flowers with reduced petals Bees/Butterfly Pollination: Bright color, nectaries, scent. They sip nectar, get pollen on coats, transfer pollen from flower to flower Bird Pollination: Nectaries, bright colors, tube-like flowers Moth Pollination: White petals, open at night Fly Pollination:Rank odor, flesh colored petals

10 Pollen Grain Anther Sac
Pollen grains contain two haploid cells produced through meiosis. 1- The Tube cell – will grow the pollen tube. 2- The Generative cell – will go through mitosis to create two sperm cells.

11 Ovary Each ovule within an ovary has a micropyle (an opening for the pollen tube). The ovules’ megasporangium undergo meiosis to produce four haploid cells (3 die leaving 1 megaspore) The megaspore undergoes mitosis 3 times to produce 8 haploid cells within the embryo sac.


13 Fertilization After pollen lands on the stigma, a pollen tube grows down through the style to ovary Generative cell creates the two sperm nuclei Double fertilization occurs: one sperm fertilizes the egg one sperm the two polar nuclei together

14 Result of Double Fertilization
The sperm nucleus and egg nucleus join to form a 2n (diploid) embryo The other sperm nucleus and the two polar nuclei join to form a 3n (triploid) endosperm. The endosperm is the food supply for the embryo. First link

15 Seed and Fruit Development
After fertilization, the petals and sepals fall off flower Ovary “ripens” into a fruit The ovule develops into a seed

16 Seed Dispersal Mechanisms- Allow plants to colonize new areas and avoid shade of parent plant
Wind Dispersal - Flight mechanisms, like parachutes, wings, etc. Ex. Dandelion, maples, birch Animal Dispersal - Fleshy fruits which animals eat, drop undigested seeds in feces or burrs which stick to animals’ coats

17 Gravity Dispersal - Heavy nuts fall to ground and roll
ex. acorns Water Dispersal - Plants near water create floating fruits ex. coconuts

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