Need Help from a Botanist - am new to forum I am writing a children's story on the Mesquite Trees found in our SW deserts. I am trying to SIMPLY explain how the roots get water into the tree and the tree's behavior during a drought. This is my text. Any Botanist out there who can direct me? Plants and trees have little microscopic pores called stomata in their leaves that allow the passage of carbon dioxide and oxygen (all part of photosynthesis). These same pores allow water to escape. During a drought, the stomata close and the leaves dry and fall. The tree is preserving its water within the limbs, trunk and roots as its stage of dormancy. The roots of plants/trees having to live with low water supply, produce proteins in the cell structure of their roots. When there is water, the difference between the minerals in the root and the water in the soil create pressure pulling water up the root into the tree. This process is called osmosis. Other forces from the passage of oxygen and carbon through the stomata also create pressure moving water to all parts of the tree.