Explain the rate of transpiration between 5 am and midday shown in Figure 9.

Use Figure 9 to calculate the percentage increase in the rate of transpiration from 1 pm to 2 pm.

Percentage increase in rate of transpiration ______________ %

The higher rate of transpiration at high tide shows that the mangrove tree is absorbing water from the sea water surrounding its roots.

Describe an experiment that you could do to investigate whether the mangrove root cells have a lower water potential than sea water.

You are given: • a piece of fresh mangrove root • sea water • access to laboratory equipment.