Question

Cholodny-Went theory is related with

• A. Turgor movement
• B. Chemotropism
• C. Phototropism
• D. Phototropism and geotropism

Answer 1

The correct option is D Phototropism and geotropism

The Cholodny-Went model, proposed in 1927, is an early model describing tropism in emerging shoots of monocotyledons, including the tendencies for the shoot to grow towards light (phototropism) and the roots to grow downward (gravitropism). In terms of phototropism, the Cholodny-Went theory proposes that:

(a) Auxin is synthesized in the coleoptile tip,

(b) The coleoptile tip perceives the asymmetric illumination and this causes auxin to move into the un-irradiated side,

(c) Auxin moves down the coleoptile so that lower regions develop an auxin asymmetry,

(d) The higher auxin concentration on the un-irradiated side causes the coleoptile to bend toward the light source.

Thus, the correct answer is option D.