9-16-13 mpx stem why do plants need water?

http://www.clemson.edu/extension/horticulture/nursery/irrigation/why_plants_need_water.html

http://scienceline.ucsb.edu/getkey.php?key=3551

http://www.pa.msu.edu/sciencet/ask_st/092194.html

Why do plants need water?

First off, plants are made out of roughly 90% water. This means that the absorption of water is much more important to plants than mammals. Mammals are approximately 75% water. Even though plants biggest need is water, they cannot just walk off and find it. This makes it even harder for a plant to flourish.
Plants do not have blood. They need to stay hydrated so the nutrients that they collect from photosynthesis can be distributed throughout the whole body. This is called transpiration.
Water is also needed when photosynthesizing. Water is needed to produce the necessary carbohydrates the plant needs. Without water, plants would have not way of getting the needed nutrition and die.
When plants transpire, they switch out water for carbon dioxide. Carbon dioxide is used to make food for the plant. Without water, a plant would not be able to exchange anything for carbon dioxide, which means it would not be able to produce nutrients for itself.
  Because plants are 90% water, if the plant does not have much water, it will wilt. Plants use the water in its body to keep it steady. It fills the cells in its body to keep its shape.