NEET 2014 Biology Paper

There are various bioassays to determine the concentration of auxin hormone in the plant. The Avena coleoptile test is a bioassay firstly done by F. W. Went. It is for IAA (indole-3-acetic acid). It measures the angle of the curvature of a decapitated coleoptile after placing an agar block containing auxin on one side. It is seen that when coleoptile tips are placed on agar, agar produced bending when placed on one side of freshly cut coleoptile stumps. This is due to the polar movement of auxin in the stem.