B8: Reproduction in Plants

Identify and draw the parts of an insect- pollinated flower 1 8 Stamen 9 2 7 6 3 5 4

Insect-pollinated flower parts Function Sepal Leaf-like structures that protect the flower bud Petals Brightly coloured and scented to attract insects Stamen The male sex organ Anther Part of the stamen where pollen is made Filament The stalk which holds the anther Carpel Female sex organ Stigma Top of the carpel where the pollen lands Style Pollen travels down here to reach the ovary Ovary Contains the ovules Ovule Contains the female gamete (egg cell)

Identify and draw the parts of a wind-pollinated flower Sepal Anther Ovary Stigma Filament Stamen 1 5 2 4 6 3

Differences between insect- and wind-pollinated flowers Feature Insect-pollinated Wind-pollinated Description Reason Petals Large, bright To attract insects Dull or absent No need to attract insects Scent Often sweet No scent Nectar In nectary No nectar Pollen quantity Moderate Less wastage Great quantities Most pollen does not reach another flower Pollen Sticky or spiky To stick to insects Light and smooth So it can blow in the wind Anthers Firm and inside the flower To brush against insects Loosely attached and dangle out To release pollen into the wind Stigma location Inside the flower Insect will brush against it Hangs outside the flower To catch drifting pollen Stigma structure Sticky coating Pollen will stick to it Feathery or net-like To catch the drifting pollen

Pollination The transfer of pollen grains from the anther to a stigma of a plant of the same species Insects and wind are 2 agents of pollination Birds and bats and some mammals are others When the anther is ripe, it will split, releasing the pollen Insect-pollinated flowers provide an incentive for bees etc to visit the flower The bee feeds on the nectar stored at the base of the flower, and gets coated in pollen from the anther When the bee visits anther flower for more nectar it will brush the second stigma with pollen – pollination occurs Pollination in action pollination

Fertilisation Once the pollen lands on the stigma, the grains start to grown down the style towards the ovary The nucleus of the male gamete fuses with the egg cell nucleus in the ovule – fertilisation has occurred. The zygote divides and grows into the embryo. The ovule becomes the seed The ovary is the fruit with the seeds inside Seed production

Germination The growth of the embryo, forming a radicle (small root) Water, oxygen and a suitably warm temperature are needed for germination water swells the seed, breaking the seed coat and allowing the cells to develop vacuoles and swell swelling of the seeds causes the radicle to grow water allows the embryo to access the food stores in the seed Oxygen is required for respiration to provide energy the warmer temperature is needed for the enzymes to work efficiently Seed growth