Plant reproductive parts
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Scanning electron micrograph of part of a thale cress flower, showing the male and female reproductive organs. The female part of the flower, the pistil (the blue feathery structure on an olive green stalk), is at the centre of the image and contains egg cells (ovules) housed in an ovary. It is surrounded by the male parts, the stamens, which have their anthers coloured light green and their filaments brown. Some of the anthers are open, revealing pollen grains ready for dispersal (the light green/yellow spherical structures, for example in the anther in the top-left of the image). The pollen grains contain the male sperm cells. After an egg cell is fertilised by a sperm cell it develops into a seed. The petals are coloured purple. Thale cress, or Arabidopsis thaliana, was the first plant to have its entire genome sequenced, and is widely used as a model organism in molecular and plant biology research. The width of the image is 1200 micrometres (1.2 mm).
Why is Arabidopsis used as a model organism?
Arabidopsis thaliana has a very short life cycle of about six weeks from germination to seed maturation. It is also easily grown and can be cultivated in small spaces, which makes it ideal for growing in a laboratory. Furthermore, it has had its genome sequenced, and a large collection of Arabidopsis plants carrying characterised mutations are available. These advantages have made Arabidopsis a model organism for studying flowering plants, and consequently it is used in plant research laboratories all over the world.
Where is Arabidopsis thaliana found?
Arabidopsis is a small flowering plant native to Europe and Asia but is now found in other parts of the world with temperate climates. It is a small annual weed that grows in free-draining sandy or gravely soil and is often found in gardens, on wasteland and by railway lines. It belongs to the mustard family and produces small white flowers from March to June. Arabidopsis thaliana has also completed a life cycle in space aboard the International Space Station.