Explain why it matters for plants to open and close their stomata in a daily cycle.
Fig. 2.1 presents the outcome of an experiment used to track this rhythm across three days and nights in the plant Arabidopsis thaliana. The proportion of stomata that are open is shown. Each day had 14 hours of light (white bar) and each night had 10 hours of darkness (black bar). Fig. 2.1 indicates that the proportion of open stomata rises during the first seven hours of the experiment. Describe the order of changes in the guard cells that causes stomata to open.
The experiment was carried out again using A. thaliana plants that were kept in darkness from 14 to 96 hours. The results are given in Fig. 2.2. Using Fig. 2.1 as a reference, explain what Fig. 2.2 shows about the roles of genes and the environment in regulating the rhythm of stomatal opening and closing in A. thaliana.