A laboratory investigates the effect of auxin on segments taken from the growing regions of two unidentified plant organs, P and Q.
All segments had the same initial length. Segments were immersed evenly in either a solution containing no auxin or a solution containing auxin. The mean increase in length after 24 hours was recorded.
| Organ | Mean increase in length with no auxin in mm | Mean increase in length with auxin in mm |
|---|---|---|
| P | 1.1 | 3.7 |
| Q | 2.8 | 0.9 |
Explain which of organs P and Q is a shoot and which is a root.
A new segment from organ Q is held vertically in darkness. The same concentration of auxin is supplied only to its left side.
Predict the direction in which the segment will curve. Explain your answer.
105 exam-style questions on Edexcel GCSE Biology 6.3 Plant hormones, covering 6.3.1 Plant hormones and tropisms and 6.3.2 Commercial uses of plant hormones. Each one has a worked solution and a mark scheme showing where the marks go.