Fertilisation and pollination L/O: To understand the processes of fertilisation and pollination. Starter: Draw and label a diagram of a flower. Extension: Write the function of each part. Success Criteria: A* - Explain in detail the processes of fertilisation and pollination. A – Explain the processes of fertilisation and pollination. B – Explain the importance of pollination in agriculture. C – State what fertilisation and pollination are.

Pollination Pollination involves the transfer of pollen (male gamete) from the anther to the stigma (outermost female part) If it is in the same flower it is called self-pollination. If between different flowers it is called cross-pollination Plants are pollinated by insects or the wind.

Pollination Pollination

Sexual reproduction in flowers

Pollination Feature Insect pollinated plants Wind pollinated flowers Petals Large, brightly colours; many are patterned to guide insects in Small, usually brown or green Scent Often scented to attract insects Not scented Nectar A sugary liquid made to attract insects No nectar Stigma Found inside the petals so insects brush against it on way to nectar Large, feathery; hangs outside the petals to collect pollen from the air; may be sticky Anthers Inside the petals so insects brush past on way to nectar Hang outside petals so pollen blown away by wind Pollen grains Relatively few, large and sticky to attach into the insects that visit the flower Many, small and light to float easily in the wind

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). Botanical gardens booklet 2 World of plants –fruits and seeds green

Fertilisation SQA-Describe the growth of a pollen tube and fusion of gametes SQA- Describe fertilisation and fruit formation Botanics fruit formation Tomato- juicy fruit Bean- pod Sycamore- small dry nut Hazelnut- hard outer wall Botanics info Pollen tubes measured were 6, 9, 11 cm long!!

Let´s have a look at some pollen tubes underneath the microscope! The pollen grain grows a tube. The tube reaches an ovule. The gamete nuclei fuse (fertilisation) and a zygote (seed) forms.

Fertilisation

Fertilisation Pollen arrives on stigma, pollination takes place For fertilisation to happen, male nuclei from pollen grain have to travel down style and into ovary to fuse with nuclei of ovule Pollen grain and ovules both have more than one nuclei Ovule- nucleus will go on to form embryo in seed (egg nucleus) Nuclei that will form the food store for developing embryo is the endosperm nucleus All nuclei in ovule have to fuse with male nuclei from pollen grain for fertilisation to occur Pollen grain attaches to top of stigma in pollination

Fertilisation A pollen tube grows out of pollen grain down style Pollen tube grows into ovary and into ovule Here, one male nuclei from pollen grain fertilises the egg nucleus in the ovule to form a zygote Variety is introduced when male and female nuclei fuse Zygote grows and divides to develop into an embryo Other male nucleus fuses with 2 more female nuclei to form endosperm nucleus Fertilised endosperm nucleus and egg cell nucleus of the ovule give rise to a seed Endosperm forms food store, while the tissue that results from the female egg nucleus forms the embryo plant If there are several ovules, most or all of them are fertilised As seeds form, the ovary grows into a fruit, which surrounds and protects seeds

Fertilisation Once fertilisation has taken place the zygote (fertilised ovule)becomes a seed, and the ovary becomes a fruit. The petals die and fall off. The plant seeds are in the fruit. Soft and juicy- tomato, plum and apple Hard and dry- sycamore, dandelion

What are fruits like? The fruits can be: - soft & fleshy - hard & dry Write the names of as many fruit as you can think of as a group and write them on a card Stick them on the correct side of the class Everyone pick a fruit card and your job is to bring that piece of fruit in for next lesson!

To finish off….. http://www.youtube.com/watch?v=sc6snhtpd4g&playnext=1&list=PL2CD6FD59EA58C94A