1. Reproduction in Flowering Plants

2. Types of reproduction
Asexual – the production of clones; no other plant necessary (« I can do it own my own, thanks! ») Sexual – gametophytes formed; pollination is necessary

3. Asexual reproduction Also called vegetative reproduction
Asexual reproduction occurs in various ways:
- production of rhizomes (modified stems);
could be ‘eyes’ on potatoes
- from fragments of roots or shoots (e.g dandelions, quack grass)

4. Costs and benefits Benefits? Advantageous traits will be passed on
Less energy than sexual reproduction
Faster
Only one plant needed
Young plantelets are more robust and survive better

5. One big cost…..
No diversity in genetic clones – if the environment changes quickly or if there is a disease or insect outbreak, the entire population will die….

6. Human uses of asexual plant reproduction
Gardeners, nurseries Reproducing copies of plants with desirable characteristics using methods such as:
Stem cutting – in water or soil where new roots will form
Grafting - branch from plant with desirable features is attached to stem of other plant (common
in orchards)
Tissue culture – piece of plant in test tube
with growth media

7. Sexual reproduction
The product of sexual reproduction (in flowering plants) is a seed. Seed function: - to protect and nourish the embryo - to move the embryo to a new location

8. Costs and benefits Benefits: High level of genetic diversity
Seeds are dispersed; less competition for resources
Seeds can remains dormant for a long time
Cost?
- Lots of energy – specialized structures

9. Sexual reproduction Similar in angiosperms and gymnosperms
Meiosis forms gametophytes – pollen grain and ovule
Pollen grain is carried to ovule (in the process of pollination) where fertilization occurs
Embryo grows by mitosis
Germination occurs

10. It starts with pollination
Pollination happens by wind only in gymnosperms and both wind & animals in angiosperms (pollinators)
Conifers have both male and female cones on the same tree
Pollen grain must land close to an ovule on a female cone (most don’t), then fertilization occurs (can take about 13 months)

11. Angiosperm pollination
Animal-pollinated flowers are very showy and colourful while wind-pollinated flowers can barely be noticeable (maple tree)
Some plants can have both female and male parts (e.g. corn), can self-pollinate
Some plants only have male or female flowers (must cross-pollinate)

12. From Pollen to Ovary The pollen grain grows a pollen tube
towards the ovary, which contains the ovule and egg cell (female gamete).
pollen tube
ovary containing ovule 12

13. 9Ad
Fertilization
Fertilisation takes place when the ‘sperm’ nucleus from the pollen grain enters the egg cell. The resulting zygote eventually turns into a seed.
pollen tube with pollen grain nucleus
ovule
Embryo grows inside the ovule.
egg cell 13

14. Zygote to Embryo
The zygote will grow through the process of mitosis to form an embryo (The ovule is now called a seed and is covered by a protective seed coat.)
seed
seed coat
food supply
(cotyledon)
embryo

15. Fruit Formation Some plants produce fruit containing seeds.
Fruit: Mature ovary
Tissue surrounding the embryo develops into fruit.
When the fruit is fully developed it drops off the plant, or is carried away by an animal.
When fruit decomposes it releases the seed and germination can occur.

16. Germination A seed requires moisture (water) to germinate.
The as the embryo grows, the root and shoot break through the seed coat.
Nutrients stored in the cotyledon provide nourishment and support early development

17. Sexual reproduction in gymnosperms
Conifers (e.g pines and cedars) produce both male and female cones Male gametophytes (haploid) produced and stored in pollen grain Wind pollination gets pollen grain to female gametophyte (haploid) in ovule One sperm nuclei fertilizes the egg after a pollen tube grows into ovule (13 months)

19. Sexual reproduction in angiosperms
Seeds are contained inside a fruit – a mature ovary This fruit is an important part of the diet for many animals including humans. Sexual structure is the flower…….

20. Parts of a flower 20

21. Reproductive Parts Male reproductive organs (stamen):
Anther: produces pollen grains
Filament: supports anther above female reproductive organs
Female reproductive organs (carpel):
Stigma: sticky landing site for pollen grains
Style: tube that leads down to ovary
Ovary: contains ovules that develop into seeds

22. Reproductive Mechanisms
Pollen (male gamete) from one plant lands
on the stigma of another plant.
This is called pollination.
pollen
stigma 22

23. Monocot and dicot flowers
Monocot: Petals and stamens are always in multiples of three. Dicot: Petals and stamens are in multiples of four or five.

24. Pollination and fertilization in angiosperms
Cross – pollination: by wind or animals between flowers of different plants of the same or closely related species(pollinators) – like? Self-pollination: pollen transfer from flowers on the same plant

25. Sexual reproduction

27. Selective breeding in plants
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Selective breeding in plants
texture
size
Selective breeding and cross-breeding are carried out on plants to produce flowers and crops with desirable characteristics…
taste
colour 27

28. 9A Plant-breeding techniques
Anne the plant breeder chooses two parent plants with useful characteristics.
One plant will be the female parent. Anne removes the anthers and covers the flower with a bag. Why?
female parent
The other plant is the male parent. Its anthers develop as normal.
Anne collects its pollen and brushes it onto the female plant.
collected pollen
anthers removed
She puts the bag over the flower again. Later she collects the seeds and grows them to produce the new plant.

29. Fruit formation
A fruit – a mature ovary that helps protect and disperse the seed Fruit – can be sweet and fleshy (e.g. plums and strawberries) or dry like walnuts and wheat or vegetables (e.g. peppers, peas and squash)

30. Importance of seeds
Grain crops (like wheat) are staples around the world Greenhouses Seed collection for breeding Survival of other species on earth

31. Comparing Plant and Human Reproductive Systems
Male and Female organs
Male Gamete is pollen
Female Gamete is egg produced in ovule
Pollen nuclei fuses with egg nuclei (fertiliation)
Diploid zygote
Zygote grows into embryo
Embryo grows inside protective seed coat
Cotyledons provide nourishment
Male or Female organs
Male Gamete is sperm
Female Gamete is egg produced in ovary
Sperm nuclei fuses with egg nuclei (fertilization)
Diploid zygote
Zygote grows into embryo
Embryo grows inside protective womb
Placenta provides nourishment