A laboratory tested xylem vessels with different amounts of lignin. The same pulling force was applied to each group of vessels.
| Lignin deposition | Percentage of vessels that collapsed |
|---|---|
| Low | 42% |
| Medium | 18% |
| High | 4% |
Explain what these results suggest about the function of lignin in xylem vessels, and predict how vessels with low lignin deposition would be affected when water is pulled upwards through the plant.
80 exam-style questions on Edexcel GCSE Biology 6.2 Transport in plants, covering 6.2.1 Root hair cell adaptations, 6.2.2 Structure of xylem and phloem, 6.2.3 Transpiration and stomata, 6.2.4 Translocation of sucrose, 6.2.5 Leaf structure for photosynthesis, 6.2.6 Environmental factors on water uptake, 6.2.7 Rate calculations for transpiration, and 6.2.8 Plant adaptations to extreme environments. Each one has a worked solution and a mark scheme showing where the marks go.