Question

Avene curvature test is a bioassay for examining the activity of

• A. Auxins
• B. Gibberellins
• C. Cytokinins
• D. Ethylene

Answer 1

Answer: (A)

Auxins

Avena curvature test is a bioassay for examining the activity of Auxins. In this assay the coleoptile tips are decapitated and placed on a agar block for some time, (treated agar block) during this period the auxin rapidly diffuses into the agar block.

In the next step the treated agar block is placed at one lateral side of a decapitated coleoptile, while an untreated agar block is placed on other decapitated coleoptile. When placed in light the coleoptile with the treated agar block bends in a direction opposite to that of the agar block resulting in growth of the coleoptile, however, no change occurs in the decapitated coleoptile with untreated agar block.

Proving that chemical substance responsible for growth in the coleoptile is present in the tips and is auxin.

So, the correct answer is 'Auxins'