Question

The first scientist associated with the discovery of auxins in plants is

• A. Haagen Smit
• B. Boysen-Jensen
• C. Darwin
• D. Yabuta

Answer 1

The correct option is C Darwin

Charles Darwin (1880) the great evolutionist had hypothesized the presence of growth substances in plants. In his book, 'The power of movement in plants', Darwin has described the experiments concerning the growth movements in canary grass. He had noticed the unilateral bending of the shoot tip (coleoptile) towards the source of light. Charles Darwin and his son Francis discovered in 1880, that the phototropic stimulus is detected at the tip of the plant. The Darwins used grass seedlings for their experiments. When grass seeds germinate, the primary leaf pierces the seed coverings and the soil while protected by the coleoptile, a hollow cylindrical sheath that surrounds it. Once, the seedling has grown above the surface, the coleoptile stops growing and the primary leaf pierces it. The Darwins found that the tip of the coleoptile was necessary for phototropism but that the bending takes place in the region below the tip.

Thus, the correct answer is option C.