Water and Plant Growth

• Plants need water to grow, but more than simply providing a medium for chemical interactions, water helps give a plant form and strength. A plant that goes without water for an extended period begins to droop, because the water gave strength to the stem and leaves. With a constant source of water, the plant sags and both leaves and stems can be in danger of breaking, depending on how much weight is put on them.
  
  

Photosynthesis

• Photosynthesis is the process plants use to convert carbon dioxide and water into energy in the form of glucose, with oxygen as a byproduct. The hydrogen in water molecules forms an integral part of this process, and without it plants could not create energy at all, regardless of how much sunlight they are exposed to.
  
  

Sap

• Water is the primary ingredient in all plant sap, from the light juices of small vines to the thick, syrupy liquid trees use. All plants use their sap to transport nutrients throughout their systems. Nutrients and water from the roots need to reach the leaves, and energy molecules from the leaves need to be circulated throughout the plant to keep all parts alive. Water is the medium in which their nutrients ride.
  
  

Osmosis

• Plants do not have a heart to pump their sap like blood. Instead, they use osmosis to draw water up from the ground. Osmosis allows water to migrate into the plant and seep up into the tissues. For large plants like trees, tremendous amounts of pressure are needed to draw water all the way to the top leaves.
  
  

Waterlogged Plants

• Plants can have too much water. The roots of a plant do not only pull up water, they also work to bring in macro- and micro-nutrients found in the soil. If too much water is present, the roots cannot pull in these nutrients, and the plant begins to starve. Too much saltwater can also poison or dehydrate a plant.