Grow the seedlings of oats for Avena coleoptile test in a petri plate and let them germinate in light, so that the coleoptile forms with leaves.Cut the coleoptile stem and add agar block of auxin with different concentrations in all different oat seedlings and expose them to sunlight.Then observe the amount of bending of coleoptile stem towards the light in different samples added with different amount of auxin in the agar slab.
