The graph below shows the concentration of abscisic acid in a cherry tree during different seasons of the year - NSC Life Sciences - Question 3 - 2023 - Paper 1

From March to May, there is a noticeable increase in the concentration of abscisic acid. This rise can be attributed to environmental factors such as increasing daylight and warmer temperatures, leading to enhanced photosynthesis and higher metabolic activity within the tree, which requires more abscisic acid for processes like stomatal closure to reduce water loss.

One reason for the dormancy in cherry trees during the winter is the decreased availability of sunlight and water. During winter, cold temperatures and reduced daylight hours lead to lower energy demands from the tree, necessitating a state of dormancy to conserve resources until conditions improve in spring.