A herbaceous plant, growing in a nutrient solution, is placed inside a container with strong light. Humid air is blown through the container. The diagram shows a section through part of the plant. The rates of movement of the fluids in tissues R and S are measured. The humid air is then changed to dry air, and the rates of movement of the fluids are measured once more. Which effect does the switch to dry air have on the measurements?
- Atissue R: greatly increased upward movement; tissue S: greatly increased downward movement
- Btissue R: greatly increased downward movement; tissue S: little change
- Ctissue R: little change; tissue S: greatly increased downward movement
- Dtissue R: little change; tissue S: greatly increased upward movement