plant reproduction angiosperms (flowering plants) plants that protect their seeds within the body of...
TRANSCRIPT
Plant Reproduction
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…
Structure of a Flower1. Pistil
2. Stigma
3. Style
4. Ovary
5. Stamen
6. Filament
7. Anther
8. Petal
9. Sepal
10. Receptacle
11. Stem
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
Female Reproductive StructureThe 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
Reproductive Structures
• Petals: colourful
structures that attract pollinators.
• Sepals: surround and protect the flower bud.
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
Pollination Animation
Pollination VectorsWind Pollination: Dull, scentless flowers with reduced petalsBees/Butterfly Pollination: Brightcolor, nectaries, scent. They sip nectar, get pollen on coats, transfer pollen from flower to flower
Bird Pollination: Nectaries, brightcolors, tube-like flowers
Moth Pollination: White petals, open at night
Fly Pollination:Rank odor, fleshcolored petals
• 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.
OvaryEach 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.
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
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
Seed and Fruit Development After fertilization,
the petals and sepals fall off flower
Ovary “ripens” into a fruit
The ovule develops into a seed
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
Gravity Dispersal - Heavy nuts fall to ground and rollex. acorns
Water Dispersal - Plantsnear water create floating fruitsex. coconuts