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Part 10 Plant reproduction

worksheet 10.1

Growing plants from seeds

Most living things reproduce themselves before they die. When a living organism reproduces, it produces other living organisms that are similar to itself. Most plants reproduce themselves by producing seeds. Seeds develop from flowers. Flowers are the sexual organs of plants. The reason that plants produce flowers is to reproduce themselves. The diagram below shows a flower which has been cut in half so that you can see the different parts.

The male organ is called the stamen. The stamen consists of the anthers and the filaments. The anthers produce pollen grains which are the male reproductive cells of plants like the sperm of animals.

style

anther

stigma

pollen

The female organ is called the is pistil. The pistil consists of the stigma, the style and the ovary. In the ovary are one or more eggs or ovules which are the female reproductive cells of plants.

egg

ovary

filament

petal

Pollen is carried from the anther to the stigma by wind or insects. Insect-pollinated flowers attract insects by producing a sweet substance called nectar, a strong smell and large coloured petals. Most fruit and vegetables are insect-pollinated.

Wind-pollinated flowers do not have to attract insects so they are usually small and green and do not produce nectar, a strong scent or bright petals. The anthers usually hang out of the flowers so that the pollen can be carried by the wind. The stigmas also hang out of the flowers and are usually hairy or feathery to trap the pollen carried by the wind. All grasses and cereals such as rice, wheat and maize, are pollinated by wind.

When a pollen grain lands on the stigma, it grows down the style until it reaches the ovary and then fertilises an egg. The ovary then changes into the fruit and the eggs change into the seeds.

90

GROWING PLANTS FROM SEEDS

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