1. Sexual Reproduction in Flowering Plants
c) Fruit Formation & Dispersal

2. Learning objectives Outline fruit formation.
Outline seedless fruit production
Outline fruit & seed dispersal and give with examples of wind/water/animal/self dispersal
Explain & emphasise the need for dispersal

3. Endospermic & Non-Endospermic Monocots & Dicots
Seed formation
Endospermic & Non-Endospermic
Monocots & Dicots

4. Seed Formation
The zygote grows repeatedly by mitosis to form an embryo
An embryo consists of a plumule (future shoot), a radical (future root) and cotyledons (food stores needed for germination)
3n Endosperm nucleus
2n Zygote

5. Seed Formation
The endosperm nucleus (3N) divides repeatedly to form the endosperm in endospermic seeds. This endosperm acts as a food store for the developing seed
e.g. maize
3n Endosperm nucleus
2n Zygote

6. Seed Formation
In non-endospermic seeds the endosperm is used up in the early stages of seed development so the food is stored in the cotyledons
e.g. bean
3n Endosperm nucleus
2n Zygote

7. Seed Formation Endosperm Food store for developing embryo
Embryo Plumule, radicle, cotyledons
Integuments, becomes the seed coat

8. Seed Formation
If all the endosperm is absorbed by the developing embryo the seed is a non-endospermic seed e.g. broad bean

9. Seed Formation
If all the endosperm is not absorbed by the developing embryo the seed is an endospermic seed e.g. Maize

10. Seed types and structure
embryo
Plumule (immature shoot)
Radicle (immature root)
Cotyledon (food supply or seed leaf)
endosperm
Food store
All seeds
In some seeds

11. Endospermic Seed e.g. Maize
Seed coat (testa)
Cotyledon
Endosperm
Plumule – will develop into a new shoot
Radicle – will develop into a new root

12. Non-Endospermic seed e.g. Broad Bean
Seed coat (testa)
Cotyledon
Plumule
Radicle

13. Non–endospermic and Endospermic seed
Cotyledon
Plumule
Radicle
e.g. Broad Bean
e.g. Maize

14. Classification of seeds
Classified according to two features:
Number of cotyledons (Seed leaves)
Monocotyledon – one cotyledon
E.g. Maize
Dicotyledon - Two cotyledons
E.g. Broad bean
Presence of endosperm
Present – Endospermic e.g. maize
Absent – Non-endospermic e.g. broad bean

15. Broad Bean – Non-Endospermic Dicot
Testa
2 Cotyledons

16. Differences between monocots and dicots
Feature
Monocot
Dicot
Number of cotyledons 1 2
Venation
Parallel
Reticulate (Net)
Vascular Bundle arrangement
Scattered
In a ring
Number of petals
Usually in multiples of 3
Usually in multiples of 4 or 5

19. Fruit formation Seedless fruits Fruit and seed dispersal

20. Fruit Formation
The ovule becomes the seed
The ovary becomes the fruit

21. Fruit Formation A fruit is a mature ovary that may contain seeds
The process of fruit formation is stimulated by growth regulators produced by the seeds

22. Seedless Fruits Can be formed in two ways Genetically
Either naturally or by special breeding programmes
e.g. seedless oranges

23. Seedless Fruits Growth regulators e.g. auxins
If large amounts of growth regulators are sprayed on flowers fruits may form without fertilisation
e.g. seedless grapes

24. Fruit and seed dispersal
Need for dispersal
Minimises competition for light, water etc.
Avoids overcrowding
Colonises new areas
Increases chances of survival

25. Types of dispersal
Wind
Water
Animal
Self

26. Methods of dispersal Wind Sycamore and ash produce fruit with wings
Dandelions and thistles produce fruit with parachute devices
Both help to disperse the seeds more widely using wind

27. Methods of dispersal Water
Light, air filled fruits that float away on water
E.g. coconuts, water lilies

28. Methods of dispersal Animal Edible fruit
Animals attracted to bright colours, smells and food
Seed passes through digestive system unharmed
E.g. strawberries, blackberries, nuts

29. Methods of dispersal Animal Sticky fruit
Fruits with hooks that can cling to the hair of an animal and be carried away
E.g. burdock, goose grass

30. Methods of dispersal Self
Some fruits explode open when they dry out and flick the seed away
E.g. peas and beans

31. Go to the next stage in the life cycle
Dormancy & Germination
Thanks to PDST biology team