Sexual Reproduction in Plants 1

Sexual Reproduction in Plants Adult Plant 1. Flowers and Pollination when the pollen is transferred from anther to stigma 2. Fertilisation when the male and female gametes fuse 3. Seed when the embryo is dormant and is dispersed 4. Germination when the seed grows into a plant There are four stages in the sexual reproduction cycle of a plant. We’ll look at each in turn.

Adult Plant 2. Fertilisation when the male and female gametes fuse 3. Seed when the embryo is dormant and is dispersed 4. Germination when the seed grows into a plant 1. Flowers and Pollination when the pollen is transferred from anther to stigma 1. Flowers and Pollination

Flowers and Pollination stigma style ovary petal anther filament sepal stamen carpel Female part. Ovary contains female gametes (ovules). Male part. Anther contains male gametes (pollen). nectary All flowering plants reproduce sexually. Their sexual reproduction organ is the flower. Can you label these parts of a flower?

Pollination stigma style ovary petal anther filament sepal stamen carpel Female part. Ovary contains female gametes (ovules). Male part. Anther contains male gametes (pollen). nectary Pollination is the transfer of pollen from the anther to the stigma. The pollen is transferred by wind or by insects.

What’s the difference between the flowers on the left and right? Flowers and Pollination pollinated by insects pollinated by wind

Flowers and Pollination How are the flower structures different in Insect-pollinated and wind- pollinated flowers? Insect-pollinated flowerWind-pollinated flower

Wind-Pollinated Flowers

Pollen grains. Can you spot insect pollen and wind pollen?

Flowers and Pollination Feature Insect-pollinated flowersWind-pollinated flowers petals stamens carpels nectaries pollen grains Copy and complete the table to show differences between insect-pollinated and wind-pollinated flowers

Flowers and Pollination Feature Insect-pollinated flowersWind-pollinated flowers petals Large and brightly coloured, to attract insects Small and not brightly coloured (often green) stamens carpels nectaries pollen grains

Flowers and Pollination Feature Insect-pollinated flowersWind-pollinated flowers petals Large and brightly coloured, to attract insects Small and not brightly coloured (often green) stamensInside flowerOutside flower, to catch wind carpels nectaries pollen grains

Flowers and Pollination Feature Insect-pollinated flowersWind-pollinated flowers petals Large and brightly coloured, to attract insects Small and not brightly coloured (often green) stamensInside flowerOutside flower, to catch wind carpels Inside flower, stigma sticky to stick to insects Outside flower, stigma feathery to catch wind-blown pollen nectaries pollen grains

Flowers and Pollination Feature Insect-pollinated flowersWind-pollinated flowers petals Large and brightly coloured, to attract insects Small and not brightly coloured (often green) stamensInside flowerOutside flower, to catch wind carpels Inside flower, stigma sticky to stick to insects Outside flower, stigma feathery to catch wind-blown pollen nectariesPresent, to attract insectsAbsent pollen grains

Flowers and Pollination Feature Insect-pollinated flowersWind-pollinated flowers petals Large and brightly coloured, to attract insects Small and not brightly coloured (often green) stamensInside flowerOutside flower, to catch wind carpels Inside flower, stigma sticky to stick to insects Outside flower, stigma feathery to catch wind-blown pollen nectariesPresent, to attract insectsAbsent pollen grains Large and sticky, produced in small numbers Small and smooth, produced in large numbers

Flowers and Pollination Self Pollination and Cross Pollination Self Pollination is when pollen is transferred from the anther to the stigma of the same flower. This is possible because most plants are hermaphrodites (each plant has both male and female parts), so plants can pollinate themselves. In fact few plants do this, since it reduces genetic diversity. Cross Pollination is when pollen is transferred from the anther of one plant to the stigma of another. This increases genetic diversity, though it does mean that plants need to rely on wind or insect pollinators. Some plants encourage cross pollination by maturing their stigmas before their anthers, so self pollination is impossible. Pollination video from Britanica

Adult Plant 3. Seed when the embryo is dormant and is dispersed 4. Germination when the seed grows into a plant 1. Flowers and Pollination when the pollen is transferred from anther to stigma 2. Fertilisation when the male and female gametes fuse 2. Pollen Tubes and Fertilisation Pollen tube video from Science in action

Pollen Tubes and Fertilisation After landing on the stigma, a long pollen tube grows out of the pollen grain and down the style to the ovary. The nucleus of the pollen grain then moves down the pollen tube. Fertilisation takes place when the pollen nucleus (the male gamete) fuses with the ovule nucleus (the female gamete) to form a zygote.

Flowers and Pollination Dissect a flower.