Hormones213-page4 - They did a number of experiments and...

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Plant Growth Regulators - 4 Auxins The concept of chemical messengers in plants was proposed in 1880 by Charles Darwin and his son Francis who spent time looking at the phenomenon of phototropism in grass seedlings. Plant shoots are positively phototropic. When a seedling is illuminated from the side, the shoot will bend towards the light. This directional growth makes sense, since plants need light for photosynthesis. The Darwin father and son did research on grass seedlings to try and determine what controlled this differential growth. Interestingly, in their research, if the coleoptile of the wheat seedling was removed, the plant no longer curved towards light.
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Unformatted text preview: They did a number of experiments and determined that a chemical located in the coleoptile traveled to the region of elongation and effected a differential elongation of cells furthest from the light sources. In 1913 Peter Boysen-Jensen affirmed that the signal for bending was mobile. When he placed a mica slice between the coleoptile tip and the rest of the shoot, no bending occurred. The mobile chemical was subsequently studied and named auxin by Frits Went in 1926. Darwin and Darwin 1880 Boysen- Jensen 1913 Went's Experiment Confirming Chemical Control of Coleoptile Curvature...
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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