1. Bellringer-April 1, 2014 How do flowers reproduce?
Do flowers have separate male and female organs?
How do flowers pollinate? Provide examples.

2. Flowers/Reproduction
Honors Biology

3. Plant Life Cycle
Plant life cycles alternate between a sporophyte phase, which produces spores, and a gametophyte stage, which produces gametes.
A zygote divides by mitosis and grows into a mature sporophyte, or spore-producing plant.
A spore divides by mitosis and grows into a mature gametophyte, or gamete-producing plant.

5. Flowering Plant Reproduction
Pollen grains
Ovule
Flower
Meiosis
Mitosis
Flowers are modified leaves, specialized for reproduction (where pollination takes place).
Flower parts undergo meiosis to produce haploid products
pollen grain
ovule (contains egg cell)

6. Flower Sexual reproductive structure Produces egg and sperm
Fertilization takes place inside the flower
Reproduces sexually (cross-pollination) and asexually (self-pollination).

7. The flower: the defining structure of angiosperms
Reproductive structure: pollen transfer; specialized shoot with modified leaves
Sepals: enclose flower before it opens
Petals: attract pollinators
Stamens: male sex organs; anther (produces pollen), filament
Carpels (Pistil): female sex organs; stigma, style, ovary, ovules

8. *Stigma –top of the pistil, Sticky surface for pollen to stick to
Female reproductive organ
Male reproductive organ
Pistil
*Stigma –top of the pistil,
Sticky surface for pollen to stick to
*Style – connects the stigma to the ovary
*Ovary –contains ovules
( eggs)
Stamen
*Anther – produces sperm nuclei by meiosis. Sperm nuclei are enclosed by pollen grains.
*Filament – holds the anther up

9. Pollination
Flowers/fruits can be carried by wind, water, or animals to new locations, enhancing seed dispersal
Wings enable maple fruits
to be easily carried by the wind.
(a)
Seeds within berries and other
edible fruits are often dispersed
in animal feces.
(b)
The barbs of cockleburs
facilitate seed dispersal by
allowing the fruits to
“hitchhike” on animals.
(c)
Figure 30.9a–c

10. Pollination: Transfer of mature pollen grains from the anther to the stigma

11. When a pollen grain lands on the stigma, it germinates and a pollen tube grows down through the style to an ovule (egg)

12. Fertilization
The sperm travels through the pollen tube to the ovule. The sperm & egg fuse forming the zygote (fertilized egg) –this grows into the plant embryo (cells grow by mitosis)

13. Self pollination –pollen from same flower
*Self pollination –pollen from same flower *Cross pollination – pollen from a different flower - more variation

14. Pollination is the transfer of pollen from the anther to the stigma
Click to view the animation
This is an example of cross-pollination as the pollen travels from one flower to a different flower. This is desirable in plants as it promotes variation.
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

15. Self-pollination occurs when pollen falls from the anther onto the stigma of the same flower
Click to show animation of self-pollination
Self-pollination is not desirable as it reduces variation
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

16. Flowers will prevent self-pollination by either having stigma above stamen or…
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

17. …by having stamen and stigma mature at different times.
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

18. The ovary and zygote (fertilized ovule) develop and ripen.
*The ovule forms the seed and the ovary forms the fruit.
Seed = embryo + stored food + seed coat
Fruit = ovary wall, mechanism for seed dispersal
A fruit is a ripened ovary

19. Fruits Form when ovary with ovules (eggs) ripens
May be dry and hardened (nuts)
May be enlarged and fleshy (berries, apples, tomatoes) …TASTY!!!
Used to help disperse seeds

20. Flowers, Fruits, and vegetables
A fruit is the part of the plant that develops from a flower. It's also the section of the plant that contains the seeds. (Protects the seeds).
The other parts of plants are considered vegetables. These include the stems, leaves and roots — and even the flower bud.

21. Dead Center sits the tomato. Why?

22. Dead Center sits the tomato. Why?
Botanically speaking, a tomato is a fruit because it is a seed-bearing structure that develops from the ovary of a flowering plant.
In the culinary world
sweet = fruits and savory = vegetables: this includes botanical fruits as eggplants, bell peppers, and tomatoes.