Transpiration is the process where plants absorb water through the roots and then give off water vapour through pores in their leaves. An example of transpiration is when a plant absorbs water in its roots. Cohesion is when particles stick together within the same substance such as water. When plants release water through transpiration, the job of cohesion is to move water through the xylem. When the water leaves through the stomata new water is pulled into the leaf by this pull between water molecules.

Plants need to transpire because more transpiration leads to more suction of water from the roots which leads to more dissolved nutrients uptake which helps with the plants growth. Plants also need to transpire as evaporation allows the plants leaves to cool. One factor that affects transpiration is light, this affects it as in bright light transpiration increases because the stotoma opes wider to allow more carbon dioxide for photosynthesis. Temperature also affects transpiration as transpiration is faster in higher temperature this is because evaporation and diffusion is faster in higher temperatures. Another factor that affects transpiration is wind as its faster in wind this is because water vapour is removed quickly by air movement. The last factor that affects transpiration is humidity. When its humid transpiration is slower, this is because the diffusion of water vapour slows down if the leaf is already surrounded by moist air.

The xylem are columns of hollow, dead reenforced cells. The xylem moves water and minerals from leaves to the rest of the plant. Factors that speed up transpiration will increase the rate of water uptake from the soil. When there isnt a lot of water or the roots are damaged, it increases a plants chance of survival if the transpiration rate can be slowed down. Plants can do this themselves by wilting. Wilting is when the leaves become limp through heat or loss of water.