To investigate what causes plants to lose water.
What do you want to find out?
I will try to find out what conditions cause plants to lose water. I will then try to prove my idea by conducting a number of experiments.
What scientific knowledge do you have which might be useful in planning your investigation?
I know that Transpiration is the loss of water from the leaf surface, which helps to draw water up through the plant. The Surfaces on a cell are moist; this is because water evaporates from them into the spaces between the cells.
When transpiration takes place water vapour diffuses out of pores, these pores are called stomata. This happens between the cells at the leaf’s surface. Leaf cells have to replace this lost water; they do this by replacing it with a solution inside xylem vessels, tiny tubes running through the plant from the root to the shoot.
There are a lot of different factors and conditions that affect the rate of transpiration. If the temperature increases, the water molecules evaporate from cell surfaces more quickly. If it is a windy day the moving air takes water vapour away from the leaf surface, increasing the diffusion gradient. When dry is around the leaf water from the cells evaporate faster. If the plant has more stomata transpiration happens faster. The amount of waterproof waxy cuticle the leaf has on the upper surface will prevent water moving through it.
The amount of light that shines on the leaf will also have an affect on the leaf. The amount of surface area that the leaf has, if the leaf is small and thin, that will mean that less sunlight will get to it and less transpiration takes place.