Outline4 marksStandard
A student investigated the effect of auxin on stem elongation in pea seedlings. Segments of stem were incubated in a buffered solution with or without auxin (indole-3-acetic acid). The length of each segment was measured at the start and after 6 hours. The results are shown in the table.
| Treatment | Initial length (mm) | Final length (mm) | Change in length (mm) |
|---|---|---|---|
| Without auxin | 10.0 | 10.2 | 0.2 |
| With auxin (1 µmol dm⁻³) | 10.0 | 13.6 | 3.6 |
Outline the mechanism by which auxin stimulates elongation growth in plant stems, referring to the acid growth hypothesis.