Flowering Plant Sex!

1. Flowering Plant Sex!

2. Carpel female parts Stigma Petals Stamen male parts Style Anther Ovary Filament Ovules Nectaries Sepals Label your diagram on your worksheet

3. What do the parts do? Stamen- anther produces male sex cells (pollen) from pollen sacs. Anthers located on filaments Sepals- protect the flower when it is a bud, join togethet to make a calyx Carpel - stigma traps pollen; often sticky, landing platform for pollen Style is where pollen tube grows down to female sex cells. Petals- colourful to attract insects, birds, animals… Nectaries- give out sugary liquid to attract insects Add these notes into your table on your worksheet Carpel- ovary produces female sex cells (ovules)

4. Pollination Pollination: the transfer of pollen (male gamete) from the anther to the stigma (outermost female part) • If it is in the sameflower: self-pollination • If between differentflowers: cross-pollination • Plants are pollinated by animals( insects, birds or mammals) or wind

5. Adaptations for animal pollination • Anthers firm, inside flower, to brush against insect/animal • Big, bright petals, attract insects/birds/animals • Moderate quantity of pollen (less waste) • Sticky spiky pollen • Sticky stigma, large landing site • Stigma inside flower • Nectar for many flowers – smelly, sweet, sticky

6. Adaptations for wind pollination • Small inconspicuous petals(no need to attract pollinators) • Many flowers on tight clusters to block the wind • No nectary • No scent • Pollen light, smooth, water-tight, dry • Large, feathery stigmata • Huge quantities of pollen – much doesn’t reach a useful destination • HAY FEVER

7. Adaptations to prevent cross-pollination • Anthers located far from (often below) stigma • Flowers are separate male and female forms (staminate/pistillate) • Individual flowers are not hermaphrodite

8. Some fine animations about pollination… • form Oxford University Press • the beauty of pollination from Louis Schwartzberg • stories about pollinators from the BBC

9. Fertilisation

10. Fertilisation Pollen germinates as a consequence of conditions on the stigma Pollen tube grows in response to chemicals produced from the ovule: chemotropism Pollen tube secretes hydrolytic enzymes in order to drill down towards the ovule Pollen tube bursts into the ovule to fertilise the ovule and form a SEED plant fertilisation slideshow

11. Fertilisation Fertilisation involves the fusion of the nucleus of the male gamete (in the pollen) with the nucleus of the female gamete (in the ovules).

12. Fertilisation

13. Let´shave a look at somepollentubesunderneaththemicroscope! • The pollen grain grows a tube. • The tube reaches an ovule. • The gamete nuclei fuse (fertilisation) and a zygote (seed) forms.

14. Fertilisation Once fertilisation has taken place the zygote (fertilisedovule)becomes a seed, and the ovary becomes a fruit. The petals die and fall off. The plant seeds are in the fruit.

15. FruitFormation and SeedDispersal

16. Fertilised ovules become seeds • Ovule containing the frtilised zygote divides by mitosis to form an embryo plant and begins to grow • Ovule dries up to become a seed – water is sucked out, so that the seed becomes dormant • The OVARY grows into FRUIT,protected by skin (the pericarp)

17. Fruits! • The function of fruit is to protect, and promote dispersal of, the seed • Fruits are officially defined as ovaries folowingfertilisation and contain seeds • All fruits have one or more seeds, and two scars – one where it was attached to the plant, and one where the style and stigma were attached to it

18. Seed Dispersal- why? • Seeds must be carried away (dispersed / scattered) from the parent plant to: • Reduce overcrowding • Reduce competition for: • - Water • - Light • - Nutrients

19. Learning about Seed Dispersal Use the next few slides, the Blog link and the video clip to help you fill in the rest of your worksheet relating to seed dispersal

20. A wee introduction to seed dispersal!

23. Seed Germination: the movie

24. The life cycle of a plant • There are 7 stages in the life cycle of a plant. seed / fruit Formation seed dispersal fertilisation pollination germination development flower formation

28. Seed Structure • Parts are: Seed coat Forms a tough protective layer Embryo shoot Embryo – grows into plant Food store Provides the embryo plant with food. Embryo root

30. Seed germination

31. Seed anatomy • Cotyledons: Food source: (starch and protein): surrounded by protective testa • Testa has a tiny hole called micropyle, with a scar (hilum) which joined seed onto pod • Embryo consists of radicle (which will grow into a root) and plumule: becomes the growing shoot of the plant

32. Seed germination Seeds contain hardly any water – with no water, virtually no metabolic reactions can occur Seed dormancy ensures survival in harsh conditions (cold, drought) Seeds can only germinate under a collection of optimal circumstances At germination, the seed first takes up water through the micropyle – water goes swells the seed, the testa bursts and the plant begins to grow

33. Germination conditions • Germination is the development of a new plant from the embryo in a seed. • Seeds need certain conditions to germinate: • Water • to activate enzymes which digest stored food • Oxygen • Needed for the production of energy for germination • Warmth • Needed for the enzymes to work effectively.

35. Germination • What does it need?

36. Germination needs… • Water • Oxygen • Warmth • Review fro BBC Bitesize