Frits Went's auxin experiments

Référence de la vidéo 11937921
Frits Went's auxin experiments. Animation showing the experiments carried out in 1928 by Dutch biologist Frits Warmolt Went (1903-1990) to demonstrate the existence and effects of the growth hormone auxin in plants. He experimented with young shoots in monocotyledons such as grasses. The tips of these shoots are called coleoptiles. He cut the coleoptile from a shoot and placed it base down on a block of agar for about one hour in sunlight (left). The growth hormone auxin (red) diffuses into the agar. The block of agar, with the coleoptile removed, was put back on the cut shoot, which resumed growth for a time (not shown). If the agar block was put on off-centre (right), the stumps could be made to bend, even in the darkness. Plain agar blocks used as control produced none of these effects. These experiments demonstrated auxin-mediated responses in a young shoot. Light receptors in the growing tip of the plant are thought to respond to light by redistributing auxin, causing it to concentrate on the side of the plant away from light. At left, with light directly from above, auxin is equally distributed to the growing tissues on all sides. At right, the auxin diffuses from the off-centre agar block into one side of the plant, causing an elongation of cells on that side and a bend in the direction of growth. For this animation with labels, see K004/3652.
Licence : Droits gérés
Crédit : Science Photo Library / Biocosmos / Francis Leroy & Michael Pierard
Model Release : Non requis
Durée : 20 Secondes
Aspect ratio : 16/9
Restrictions : -

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