Pattern, frequency, and amounts of rainfall are important components to plant health. Water is an essential plant component, making up 70 percent to 90 percent of plant mass. Growth, photosynthesis (manufacture of food), nutrient transport, important chemical reactions, and the production of secondary metabolites are all dependent upon water uptake from roots. Water expands and enlarges new cells within stems and leaves, which holds them upright (turgor pressure).
During dry seasons and drought conditions, plants become stressed (Figure 1). Growth ceases, nutrient transport slows, and plants wilt as cells become water-deficient. Severe, long-term, or consecutive drought events may cause permanent damage.
Ward Gauthier, Nicole; Fox, Susan; and Wimberley, Kathy, "How Dry Seasons Affect Woody Plants" (2014). Agriculture and Natural Resources Publications. Paper 177.