Water Balance
Most adaptations in plants are to control the balance of water in plants as the right concentration of water is important if not necessary for the plants survival in any environment. (NinErrin, 2015 )
The control of water balance is very important in plants as water is needed for the plant to carry out its life processes. Plants are autotrophs which means that they produce their own food through a process called photosynthesis which is when they produce glucose (needed for respiration to produce energy) and oxygen (a waste product) by splitting water and carbon dioxide molecules using photons/ light energy at the chloroplast. Without water, it will be impossible for the plant to produce their own food/glucose via photosynthesis making it impossible for the plant to produce energy to carry out their life processes via respiration, killing the plant. Water is also important in the structure of the plant. As plants do not have any skeletons or bones for their structure, the turgidity of the plant cells are very important as the plants will droop/ wilt if the cells are plasmolysed especially in non-woody plants. Plant cells become turgid when their vacuoles are full of water and is exerting a force/pressure on the cell wall allowing the plant to stand upright. Even in hydrophytes where they are mostly supported by the water surrounding them, water is needed to keep the cell membranes moist for efficient gas exchanges via diffusion. (NinErrin, 2015 ) (SterlingTracy, 2015)
The control of water balance is very important in plants as water is needed for the plant to carry out its life processes. Plants are autotrophs which means that they produce their own food through a process called photosynthesis which is when they produce glucose (needed for respiration to produce energy) and oxygen (a waste product) by splitting water and carbon dioxide molecules using photons/ light energy at the chloroplast. Without water, it will be impossible for the plant to produce their own food/glucose via photosynthesis making it impossible for the plant to produce energy to carry out their life processes via respiration, killing the plant. Water is also important in the structure of the plant. As plants do not have any skeletons or bones for their structure, the turgidity of the plant cells are very important as the plants will droop/ wilt if the cells are plasmolysed especially in non-woody plants. Plant cells become turgid when their vacuoles are full of water and is exerting a force/pressure on the cell wall allowing the plant to stand upright. Even in hydrophytes where they are mostly supported by the water surrounding them, water is needed to keep the cell membranes moist for efficient gas exchanges via diffusion. (NinErrin, 2015 ) (SterlingTracy, 2015)
A problem plants face concerning water balance is transpiration. This is when water is lost via diffusion from inside the leaf to the outside through the stomata but this process is also what makes it possible for the water to defy gravity and travel up from the roots throughout the plant. Firstly, water is absorbed into the roots via a process called osmosis which is when water travels from an area of high concentration (the ground) to a place of low concentration (root cells) through a semi-permeable membrane (the cell wall/membrane). Then as water molecules are lost from the leaves via transpiration, the water molecules are pulled up from the roots. This is because water molecules are polar causing the water to be attracted to each other causing cohesive forces between the molecules. This causes a transpirational pull which is when as one water molecule is lost by transpiration causing the concentration of the water particles to lower in that area, it pulls another water molecule to take it’s place which pulls the water up from the roots because of the cohesive forces between the water molecules and because the water molecules move from an area of high concentration to an area of low concentration due to osmosis. This is helped by the capillary action where the water molecules are also attracted to the sides of the xylem tube due to adhesion, and the root pressure where pressure is exerted from the roots pushing the water molecules upwards. (NinErrin, 2015 ) (SterlingTracy, 2015) (OnlineBiology, 2015)
The rate of transpiration is controlled by the small pores in the leaves and the guard cells that surround those pores. If there is too much water being lost via transpiration, the guard cells will plasmolyse and shut the stomata stopping transpiration and become turgid to open the stomata again when water is in abundance. But stopping transpiration from occurring also means that the transpirational pull will stop, stopping the delivery of water and minerals to some parts of the plant. It will also stop the process of gas exchange which is necessary in order for both respiration or photosynthesis to occur and it will also cause the temperature of the plant to rise as evaporating water molecules carries off heat energies. This means that the plant needs to balance the need for water and the need for life processes like photosynthesis carefully. The rate of transpiration is also controlled by the number of stomata, number of leaves, the size of those leaves, and the outside environment like wind, temperature and humidity. As water is lost via diffusion, the greater the difference in concentration gradient between inside the leaf and outside the leaf, the faster the rate of transpiration will be. (NinErrin, 2015 ) (SterlingTracy, 2015) (OnlineBiology, 2015)
Therefore the plants adaptations will be based on controlling the rate of transpiration whether it would be to increase or decrease it, to enhance its chances of survival in its environment.
Therefore the plants adaptations will be based on controlling the rate of transpiration whether it would be to increase or decrease it, to enhance its chances of survival in its environment.