Plant Feeding System
All organisms need food to live, only plants can make their own food. Leaves are the plants food factory. This process is known as photosynthesis where carbon dioxide and water combine in the presence of light to form sugar which is the plants food.
The current thinking of how water and nutrients are moved through plants is that water is absorbed into the plant by the younger parts of the roots. The roots have very fine hair like roots at their tips which increases the surface area of the root to maximise the amount of liquid that can be absorbed. Liquid is absorbed through the hair like root system through osmosis.
From the roots the liquid is transferred to the xylem. Xylem is the portion of a plant's vascular tissues that transports water and minerals. The xylem sap flows through a plant due to the forces of transpiration(similar to evaporation), which is the evaporation of liquid from plants. Transpiration causes a surface tension to occur, that in turn causes a negative pressure in the xylem that pulls the liquid from the roots and the soil.
Liquid also moves up through a plant because of root pressure and capillary action. Root pressure occurs during times when transpiration is low but the soil is very moist, and the roots absorb too much water. Because the water accumulates in the plant, a slight root pressure is created that pushes the xylem sap to the tips or edges of leaves, where it forms drops (the process is called guttation).
During capillary action, water rises up the walls of the thin, porous xylem tube as a result of the forces of adhesion, cohesion and surface tension. Xylem tubes are made of cellulose, to which water molecules stick.