1.1. Figure 1  below shows a transection of a stem.

Figure 1

Name the vessel J and state its function.

1.2. Figure 1 shows how the changes in environmental temperature and light intensity throughout the day can cause the diameter of a spruce tree to fluctuate.

Figure 1

Using Figure 1, identify the time range during which environmental factors have the greatest impact on trunk diameter.

1.3. Using the data represented in Figure 1 and your knowledge of the cohesion-tension theory, explain the changes in trunk diameter throughout the day.

1.4. The scientist wanted to investigate the effect of wind on the transpiration rate of the spruce trees. He identified and labelled trees in the forest that were exposed to more windy conditions and ran the experiment again.

Predict what his results will show and suggest why.