The adaptations of many plants are designed to minimise water loss and balance the amount of water in the plant's cells. This is of significance as many of a plant’s life processes require water. Plants are autotrophs’ and make their own food by photosynthesizing. The equation for photosynthesis is;
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As shown, plants need water in order to photosynthesize and produce glucose, the sugar they use to create energy. Without access to water or a way to conserve it plants wouldn't be able to complete this process or create food for itself. Without food the plant would die which is why plants have adaptations. These allow the plant to control water loss and therefore ensure processes such as photosynthesis can be carried out.
Photosynthesis isn't the only reason plants need water, for mesophytes and hydrophytes, water is needed to support their structures. As plants don’t have skeletons, the cell walls and vacuoles in their cells provide support. When the cells’ vacuoles are turgid and full of water, the plant is able to stand upright, without water the plant would wither and wilt. For hydrophytes, the water often supports the plant itself. Water is also necessary for keeping the cells’ membranes moist which allows for efficient gas exchange. Water is also used to control the temperature of the plant. Without water, plants’ cells wouldn't be able to function or produce substances such as glucose, which the cells need to survive.
Photosynthesis isn't the only reason plants need water, for mesophytes and hydrophytes, water is needed to support their structures. As plants don’t have skeletons, the cell walls and vacuoles in their cells provide support. When the cells’ vacuoles are turgid and full of water, the plant is able to stand upright, without water the plant would wither and wilt. For hydrophytes, the water often supports the plant itself. Water is also necessary for keeping the cells’ membranes moist which allows for efficient gas exchange. Water is also used to control the temperature of the plant. Without water, plants’ cells wouldn't be able to function or produce substances such as glucose, which the cells need to survive.
The issue plants face when it comes to water conservation is transpiration. As water evaporates from the plant’s leaves and stomata, more water moves up the plant to replace the molecules lost. This is due to cohesion; water molecules are attracted to each other. They stick together to make a chain and as water evaporates from the plant’s leaves and stem, more molecules are pulled up to fill the space the evaporated water has left. Unfortunately for some plants, this means they are nearly always losing water. Transpiration is the main cause of water movement in plants yet there are other smaller factors contributing to this movement. Root pressure pushes water up the plant and capillary action means that water sticks to the sides of the xylem and is pulled upwards. Although transpiration results in a loss of water from the plant, it also helps keep the plant cool and allows for movement of water and other minerals around the plant.
The rate of transpiration increases when a plant's stomata are exposed to high winds and hot or dry environments, as there is a high water concentration gradient between the inside of the plant, and its environment. This means that as there is less water outside of the plant, the H20 molecules will automatically diffuse into this low concentration area in an attempt to reach an isotonic state. Subsequently, the higher the concentration gradient, the more water the plant will lose.
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