1. Sexual reproduction in plants
A flower is a leafy shoot containing the sexual organs of a flowering plant.
It is adapted for sexual reproduction.
It is a modified terminal bud typically composed of four sets of modified leaves.

2. Insect-pollinated flower

3. Floral structures

4. Diagram of an insect-pollinated flower
Petal
Stigma
Anther
Filament
Style
Ovary
Ovule
Nectar
Sepal

6. Wind-pollinated flower

7. Diagram of a wind-pollinated flower
Bract
Anther
Filament
Ovary
Stigma

8. Functions of parts of the flower
sepals
petals
Anthers
filament
Stigma
style
ovaries
Protects the flower during the bud stage
Attracts insect pollinators by colour and scent
produce and release pollen grains
positions the anther for effective pickup of pollen by the pollinating agent
collects the pollen from the pollinating agent
positions the stigma for pollen collection
site of fertilisation, protects the developing seeds, aids in seed dispersal

9. .
. . . thinking of you!
In a form of a table, compare the different structural adaptations of insect-pollinated and wind-pollinated flowers [6]

10. structural adaptations of insect-pollinated and wind-pollinated flowers
Insect-pollinated flowers
Wind-pollinated flowers
Petals large & brightly coloured to attract insects
Stigma located inside the flower where the insects have to brush past it
Anthers inside the flower where the insects have to brush past them
Stigma usually small & sticky so that pollen grains can attach from insect body
Flower often strongly scented
Large sticky or spiky pollen grains which stick to insects
Petals small or absent, if present, not brightly coloured
Stigma exposed to catch pollen grains blowing in the wind
Anthers exposed outside the flower so that wind can easily blow the pollen grains away
Stigma large & feathery to catch pollen grains blowing in the wind
Flowers have no scent
Light & smooth pollen that can be blown in the wind

11. Pollination
the transfer of pollen grains from the male part of the plant (anther of stamen) to the female part of the plant (stigma).

12. Agents of pollination
. . . the means that moves the pollen grains from the anther to the stigma.
Agents of pollination include: wind; insects; birds; water & rodents.

13. Photomicrograph of pollen grains:
Note the spikes that attach pollen grains to insect’s body.

14. What happens after pollination?
pollen grains germinates forming pollen tube
the pollen tube grows down style digesting the style tissue
the e pollen tube enters ovule through micropyle
male nucleus moves into ovule
male nucleus (male gamete) fuses with the ovum or egg cell (female gamete) i.e. fertilisation occurs
ovule becomes seed
ovule wall becomes seed coat or testa
ovary becomes fruit
stigma and the style weathers and dry up

15. Seed and fruit dispersal
This is spread of seeds & fruits some distance away from the parent plant
Dispersal allow seeds to spread out to colonise new areas so that the new plants do not compete with parent plant for light, water and mineral salts
means of seeds & fruits are:
animals
wind
water
self dispersal

16. Seed and fruit dispersal by Wind
Wind dispersed seeds such as sycamore & dandelion:
are light so that they can easily be blown by wind
have wing –like outgrowth or feathery hair projections which increase the surface area so that the seeds can ‘float’ in air for some time so they are carried over long distance from the parent plant
Sycamore seed
Dandelion seeds

17. Seed and fruit dispersal by Animals
Animal dispersed seeds includes: tomato & burr grass.
Tomato fruits:
they are fleshy (succulent), brightly coloured & scented to attract animals
Have tough seed coat to protect the seeds from being digested in the animals' gut
Burr grass:
Are covered with stiff, hooked spines which catch onto the animals’ fur to be carried long distance before dropping off

18. Advantages of seed dispersal
There is less competition, with parent plant & among seedlings for same resources such as; light, water , nutrients & space
Dispersal allow plants to colonise new areas since plants are stationary i.e. don’t move from place to place

19. External structure of a Seed

20. Internal structure of a Seed
plumule
radicle
micropyle
cotyledon
testa (seed coat)

22. Testa; protects the embryo from physical damage & attack from pathogens
Micropyle; a hole in the testa that allow water & oxygen to enter into the seed
Cotyledons; stores nutrients (starch, protein & lipids) required during germination
Plumule; grows into shoot after germination
Radicle; grows into root after germination

23. Conditions for seed germination
Seed germination is the process in which a plant emerges from a seed & begins grow
Conditions needed for seeds germination are:
Suitable temperature; for enzymes to work effectively
Oxygen; for aerobic respiration to provide energy to growing embryo
Water; for chemical reactions to occur in solution, dissolve nutrients for transportation, activate enzymes & soak testa

24. Design & carry out an experiment to investigate the conditions necessary for germination of mung bean seeds.

25. I am willing to answer questions on sexual reproduction in plants
I am willing to answer questions on sexual reproduction in plants. Thank you folks! You are such a wonderful group of students.