Reproduction in flowers Science ACE 2012

1. Reproduction in flowersScience ACE 2012 Done by: See Yong Song 2A3 19 Jonas Ng 2A3 12 Yuan Bin Da 2A3 31 Delsario 2A3 07

2. INTRO TO PLANT PARTS

4. Petals (Corolla) • It is the most conspicuous part of the plant and can be of different colours • It is usually brightly coloured to attract pollinators like bees to pollinate it and may serve as a landing platform for them.

5. Sepals (Calyx) • They are green modified leaves • They protect the other parts of the plant during the bud stage.

6. Receptacle • It is the enlarged end of the stalk • It holds the other parts of the plant in place

7. Pedicel (Stalk) • It attaches the flower to the plant • However, it is absent in some plant species (Sessile Flowers)

8. Stamen (Male Parts) • Filament - holds the anther in optimal position to release pollen grains • Anther-produces the male gametes, or pollen grain.

9. Carpel (Female Parts) • It contains the ovary, stigma and style. • The stigma is the site of pollination and it secretes sugary fluids to allow for the growth of pollen grains. • The style is a stalk that attaches the ovary to the stigma and it holds the stigma in optimal position for pollination. • The ovary that contains ovules which contains the female gametes.

10. Reproduction in Plants

11. Reproduction In Plants • All organisms must reproduce to ensure the continuity of their own species’ survival. • There are two types of reproduction: Sexual Reproduction and Asexual Reproduction.

12. Asexual Reproduction • Asexual reproduction is the process resulting in the production of genetically identical offsprings without the fusion of gametes which are reproductive cells containing half the number of chromosomes as the normal body cell.

13. Mitosis • Mitosis is a process in asexual reproduction. • It involves the division of cells to form two identical daughter cells and each has the same number of chromosones as the parent cell.

14. Sexual Reproduction • In sexual reproduction, there is the fusion of a male and female gamete to form a zygote and hence offsprings produced genetically dissimilar from parents.

15. Meiosis • Gametes are produced through a process called meiosis in sexual reproduction. • In meiosis, a cell divides and forms 4 daughter cells and each has half the number of chromosones as the parent cell.

16. Gametes • In animals, the male gamete is the sperm while the female gamete is an egg. • A gamete contains half the number of chromosones as the body cell. • In humans, body cell contains 46 chromosones.

17. Gametes • This number is called the diploid number of chromosones. • However, human gametes only contain 23 chromosones. • This is known as the haploid number.

18. Pollen grains • Anthers produce pollen grains which contain the male gametes produced by meiosis • Which will fuse with the female gamete to form a zygote.

19. Pollination • It is the process of pollen grains from anthers landing on a stigma

21. Fertilisation • It refers to the fusion of male and female gametes to form a zygote. • After pollination, the pollen grains germinate in response to the sugary fluid secreted by the mature stigma • A pollen tube grows out of each pollen grain.

22. Fertilisation • The cytoplasm and 2 nuclei, the pollen tube and generative nucleus, passes into the pollen tube which will continue to grow towards the ovary. • The cytoplasm and 2 nuclei, the pollen tube and generative nucleus, passes into the pollen tube which will continue to grow towards the ovary. • One male gamete fuses with the egg cell to form a zygote while the other gamete fuses with the central cell to form the endosperm nucleus

23. Fertilisation • Along the way, it produces enzymes to digest the tissues of the style and stigma and the pollen tube enters the ovary through an opening in the ovule wall. • The generative nucleus then divides to form two male gametes and within the ovule, the tip of the pollen tube bursts to release the male gametes. • One male gamete fuses with the egg cell to form a zygote while the other gamete fuses with the central cell to form the endosperm nucleus

24. Zygote • It is the result of fertilisation • The endosperm nucleus is also known as the tissue produced inside the seeds of most flowering plants around the time of fertilization. • It surrounds the embryo and provides nutrition in the form of starch.

25. Seeds(Offsprings) • The zygote then develops and divides to form the embryo in the seed • The endosperm nucleus develops into the food storing tissue. • The ovule will develop into the seed • The ovary into a fruit which contains the ovule.

26. Images taken From Botanical Gardens

27. Small, white flower Brightly coloured and large leaves surrounding flower Anthers and stigma are not visible, not protruding out of flower Therefore, it is insect pollinated.

28. Big, purple flowers Large and colourful petals Anthers and stigma are visible, not protruding out of flower Therefore, it is insect pollinated.

29. Big, purple flower Large and colourful petals Anthers and stigma are visible, not protruding out of flower Therefore, it is insect pollinated.

30. Small, pinkish-purple flower Small and colourful petals Anthers and stigma are visible, protruding out of flower If seen clearly, insects such as bees can be seen flying around the plant Therefore, it is insect pollinated.

31. Big, purple flower Large and colourful petals Anthers and stigma are visible, not protruding out of flower Therefore, it is insect pollinated.

32. Small, feathery flower Petals not visible Anthers and stigma are visible Therefore, it is wind pollinated.

33. A special type of plant Petals are very hairy, dull and huge Anthers and stigma can be seen protruding if seen clearly Therefore, it is wind pollinated.

34. For more images taken from botanical gardens, refer to video no.2

35. Thank You!