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Phototropic curvature is the result of uneven distribution of
A
Auxin
B
Gibberellin
C
Phytochrome
D
Cytokinins
Detailed Solution
Charles Darwin and Francis Darwin observed that the coleoptiles of canary grass bend towards a unilateral source of light; F.W. Went later isolated auxin from the tips of oat coleoptiles.
When light falls on one side of a shoot tip, auxin moves to the shaded side.
The higher concentration of auxin on the shaded side makes the cells there elongate more than those on the illuminated side.
This unequal growth bends the shoot towards the light.
Hence phototropic curvature is the result of uneven distribution of auxin.
When light falls on one side of a shoot tip, auxin moves to the shaded side.
The higher concentration of auxin on the shaded side makes the cells there elongate more than those on the illuminated side.
This unequal growth bends the shoot towards the light.
Hence phototropic curvature is the result of uneven distribution of auxin.