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© 2009 Marshall Cavendish International (Singapore) Private Limited.

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Presentation on theme: "© 2009 Marshall Cavendish International (Singapore) Private Limited."— Presentation transcript:

1 © 2009 Marshall Cavendish International (Singapore) Private Limited

2 Questions to think about… What are the parts of a flower? How do flowering plants reproduce? How do non-flowering plants reproduce? © 2009 Marshall Cavendish International (Singapore) Private Limited

3 Reproduction in flowering plants Flowering plants can reproduce from seeds. To reproduce, plants produce flowers which develop into fruits and seeds. For fruits and seeds to be produced, the flowers must be pollinated and fertilised. a tomato seed © 2009 Marshall Cavendish International (Singapore) Private Limited

4 This flower has both male and female parts. Parts of a flower Male parts Female parts © 2009 Marshall Cavendish International (Singapore) Private Limited

5 Parts of a flower The male parts of the flower are the anther and filament. o The anther contains pollen sacs which produce pollen grains. The female parts of the flower are the stigma, style, ovary and ovule. © 2009 Marshall Cavendish International (Singapore) Private Limited

6 Parts of a flower Some plants like the papaya have the male and female parts in separate flowers. male flower of the papaya plant female flower of the papaya plant © 2009 Marshall Cavendish International (Singapore) Private Limited

7 Pollination Pollination is the transfer of pollen grains from the anther to the stigma of a flower. oThe pollen grains can be transferred within the same flower. stigma pollen grains from anther © 2009 Marshall Cavendish International (Singapore) Private Limited

8 Pollination Pollination is the transfer of pollen grains from the anther to the stigma of a flower. oThe pollen grains can also be transferred from one flower to another. © 2009 Marshall Cavendish International (Singapore) Private Limited

9 Fertilisation When a pollen grain lands on the surface of a stigma, it produces a tube. The inside of the tip of the tube contains the male cells of the flower. These tubes grow down the style to reach the ovules in the ovary. Inside each ovule is an egg cell. pollen grains stigma pollen tubes style ovary ovule egg cell © 2009 Marshall Cavendish International (Singapore) Private Limited

10 Fertilisation When a pollen tube reaches the ovule, the female egg cell and male cell combine. This process is called fertilisation. yellow pollen grains on a flower © 2009 Marshall Cavendish International (Singapore) Private Limited

11 From flower to fruit After fertilisation, most of the flower parts wither and drop off except for the ovary. Inside the ovary, the ovules begin to develop into seeds. The ovary then grows bigger until it becomes a fruit. seeds develop inside the fruit, fruit grows bigger petals drop off ovary begins to swell petals wither flower (after fertilisation) © 2009 Marshall Cavendish International (Singapore) Private Limited

12 From flower to fruit Sexual reproduction involves a male and a female. The process of producing new plants from seeds involves both male and female cells. Thus, sexual reproduction takes place in plants. © 2009 Marshall Cavendish International (Singapore) Private Limited

13 Dispersal of fruits and seeds In order for seeds to grow at a suitable place, they must be scattered. Why is that so? Well, if the seeds grow too closely together, overcrowding might occur. I see! So if this happens, the young plants may not get enough water, minerals and sunlight to grow well. Thats right. Also, some fruits are scattered while the seeds remain inside them. The scattering of seeds or fruits is called dispersal. So what are the ways in which fruits and seeds are dispersed? © 2009 Marshall Cavendish International (Singapore) Private Limited

14 Dispersal of fruits and seeds Wind o Fruits and seeds dispersed by wind are often dry and light. o Some of them have wing-like structures. o They are easily carried by wind. lalang angsana dandelion © 2009 Marshall Cavendish International (Singapore) Private Limited

15 Dispersal of fruits and seeds Animals o Some fruits can be eaten by animals. o Their seeds are thrown away or passed out in the animals droppings if swallowed. kiwi papaya watermelon © 2009 Marshall Cavendish International (Singapore) Private Limited

16 Dispersal of fruits and seeds Animals o Other fruits and seeds attach themselves to animals bodies or our clothes by using hooks or stiff hairs. mimosa lovegrass © 2009 Marshall Cavendish International (Singapore) Private Limited

17 Dispersal of fruits and seeds Water o Fruits dispersed by water usually float and are carried along rivers, streams or at sea. o They often have waterproof coverings or fibrous husks to help them float in water. coconut lotus plant mangrove © 2009 Marshall Cavendish International (Singapore) Private Limited

18 Dispersal of fruits and seeds Splitting open forcefully o Some fruits split open when ripe to shoot their seeds away. cotton ladys finger rain tree © 2009 Marshall Cavendish International (Singapore) Private Limited

19 Germination Parts of a seed seed leaf baby plant © 2009 Marshall Cavendish International (Singapore) Private Limited

20 Germination baby plant A seed starts to germinate when it lands on a place with enough warmth and water. ripe fruit and seeds disperse seed germinates Photo of tomato seedling, p. 48, P5A young plant leaves shoot root First, the root of the baby plant grows out of the seed to form a seedling. seedling During this stage, the seedling cannot make its own food, but gets it energy from the food stored in its seed leaves. Next, the shoot appears and the first leaves unfold. The young plant is now able to make its own food. grows © 2009 Marshall Cavendish International (Singapore) Private Limited

21 Germination The young plant develops into an adult plant. ripe fruit and seeds disperse seed germinates Photo of tomato seedling young plant leaves shoot root seedling grows develops into adult plant with flowers When the flower of an adult plant gets pollinated and fertilised, the cycle of reproduction repeats itself. pollination and fertilisation occurs © 2009 Marshall Cavendish International (Singapore) Private Limited

22 Non-flowering plants While flowering plants reproduce from seeds, non-flowering plants reproduce in other ways. Spores o For example, ferns reproduce from spores, and do not produce seeds like flowering plants. spore bag of a fern ferns © 2009 Marshall Cavendish International (Singapore) Private Limited

23 Asexual Reproduction Underground stems o The potato is an example of an underground stem. o It can be identified as a stem because of the buds and leaf scars. o The buds can grow into new plants when the potato in buried in soil. To grow a potato plant from a cut piece of potato, each piece must contain at least one bud. bud shoot A potato © 2009 Marshall Cavendish International (Singapore) Private Limited

24 Asexual Reproduction water chestnut bud scale leaf onion shoot fleshy leaf bud stem root Underground stems o More examples: ginger scale leaf bud root buds growing into new shoots underground stem © 2009 Marshall Cavendish International (Singapore) Private Limited

25 sucker of a banana plant on the ground Suckers o Plants like banana and pineapple reproduce by developing upright shoots called suckers. o These shoots develop from a certain part of the stem. pineapple plant sucker sealing wax palm sucker of a sealing wax palm Asexual Reproduction heliconia plant sucker of a heliconia plant © 2009 Marshall Cavendish International (Singapore) Private Limited

26 Asexual Reproduction The leaves of plants like the bryophyllum, begonia, and African violet can produce new plants. Such leaves are often thick and fleshy. leaf of new plant root of new plant bryophyllum leaf bryophyllum plant © 2009 Marshall Cavendish International (Singapore) Private Limited

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