Plant ReproductionReproduction Chapter 16

Asexual and Sexual reproduction Asexual Reproduction –No gametes are involved –The new organism will be genetically identical to its parents –Plants and bacteria can reproduce this way Sexual reproduction –Male and female gametes are involved –Two parents are needed –Offspring are not genetically identical to parents

The Flower The flower is the part of the plant that is involved in sexual reproduction. Some flowers produce male gametes Some flowers produce female gametes Most flowers produce male and female gametes

Parts of the flower Sepal-protects the flower when it is a bud. Petals-attract insects Carpel-produces the egg Stamen-produces pollen which contain the male gamete.

Name the parts of the stamen and carpel

Structure of the carpel The parts of the carpel are The Stigma –where pollen grains land The style –connects the stigma to the ovary The ovary –a chamber that contains ovules The ovules – contain the female gametes

Reproduction Reproduction in flowering plants involves th following 5 stages: 1. Pollination 2. Fertilisation 3. Seed and Fruit Formation 4. Seed Dispersal 5.Germination

Pollination Pollination is the transfer of pollen from the stamen(anther) of one plant to the carpel(stigma) of another. There are two types of pollination: Insect pollination(e.g. tulip) Wind pollination(e.g. grass) Insect Pollinated PlantsWind Pollinated Plants Brightly Coloured PetalsSmall,often green petals Stamens inside the flowerStamens outside the flower Carpel’s inside the flowerFeathery, outside the flower Large sticky pollen Small light pollen Produce nectar Don’t produce Nectar

Wind Pollination

Insect Pollination

Fertilisation Fertilisation is the fusion of the male gamete nucleus(pollen) and female gamete nucleus(egg) to form a zygote. After pollination has taken place a pollen tube grows out of the pollen grain and down through the style. The pollen tube first enters the ovary and then enters the ovule. The male gamete fuses with the female gamete inside the ovule to form the zygote.

Seed and fruit formation The zygote(fertilised egg) becomes the seed. The ovary swells and becomes the fruit. The fruit protects the seed and allows them to be carried away from the parent plant. Fruits are Fleshy(tomato, apple) or dry(dandalion, sycamore)

Seed Dispersal Seeds must be carried away from the parent plant to avoid competition for light water and minerals. The 4 methods of seed dispersal are: Wind dispersal(sycamore) Animal dispersal(fruit,burdock) Self dispersal(poppy,pea) Water dispersal(coconut)

Seeds Structure of a typical seed –Plumule-forms shoot –Radicle -forms root –Testa-protects the seed –Food Store-provides food for young plant to grow.

Germination The conditions necessary for germination are: Water Oxygen Warmth Germination is the growth of a new seed

To show that Water, Oxygen and Heat are necessary for Germination Method Set up 4 Test tubes as shown below Test tube D is kept at 4 o C by placing it in a fridge. Record your results after 1 week. A=growth B=No growth C= No growth D= No Growth