1. Reproduction in Angiosperms
IB Topic

2. Reproduction in flowering plants
Flowering plants contain their reproductive organs in the flower
Flowers are often hermaphrodite structures  both male and female parts

3. Draw and Label …
A diagram showing the structure of a dicotyledonous animal pollinated flower
Sepal, petal, anther, filament, stigma, and ovary
See Figure (Clegg)

4. The Buttercup Flower

5. Parts of the flower Sepals: Collectively called the calyx
Enclose the flower in the bud and are usually small, green, and leaf like
Petals:
Collectively called the corolla
Often colored and conspicuous (may attract insects and other animals)
Stamens:
The male part of the flower
Consist of anthers (housing pollen grains) and the filament (stalk)
Carpels:
The female part of the flower
There may be one or many & they may be fused together or free standing
Each carpel consists of an ovary and a stigma (which receives pollen)

6. Addressing some vocabulary …
Pollination: is the transfer of pollen from a mature anther to a receptive stigma
The pollen may come from the anthers of the same flower or flowers of the same plant
Self pollination
Or, the pollen may come from flowers on a different plant of the same species
Cross pollination

7. So, how is that pollen transferred?
Typically by insects and wind
Insect pollinated plants typically produce nectar which attracts insects to the flower
Although in some species, pollen can be transferred by:
Birds
Bats
Running water

8. What comes after pollen transfer … ?
FERTILIZATION!!!
Can only occur after pollen has landed on the stigma and has germinated there
Fertilization is the fusion of male and female gametes to form a zygote

9. What’s double fertilization?
The pollen grain produces a pollen tube, which grows down between the cells of the style and into the ovule
The pollen tube delivers two male nuclei
One fuses with the egg
The other fuses with another nucleus  triggers the formation of the food store for the developing embryo

10. Fertilization in a flowering plant

11. How are seeds formed and dispersed?
Seeds develop from the fertilized ovule
After fertilization:
The zygote grows by mitotic division (embryonic root, stem, and cotyledon)
As the seed matures, the outer layers become the protective seed coat (testa) and the whole ovary develops into the fruit.
The water content of the seed decreases
The seed moves into a dormancy period

12. The Seed
The seed is a form in which the flowering plant may be dispersed
Seed dispersal is the carrying of the seed away from the vicinity of the parenting plant
Wind, animals, water, and explosive mechanisms help disperse seeds

13. The structure of a dicotyledonous seed (broad bean seed)