Plants ranging from small plants to tall trees have a mechanism of transport of water from the roots till their leaves. The movement of water occurs either by utilizing or not utilizing metabolic energy. It is learnt that plants have to move water along long distances than the animals. In plants, the food that is prepared by photosynthesis has to reach the root tips that are situated deep inside the soil while the water in the soil has to reach the tip of the stem. Water has to get transferred from one cell to another through the membrane. The transport mechanism in the plants is easily understood if we have the basic knowledge of the plant cell structure, its anatomy, process of diffusion, ions and chemical potential.
The materials that have to be transported in the flowering plants are organic substances, mineral nutrients, growth regulators of plant and water. The studies on transport mechanism in plants have revealed that the above substances are moved inside the plant through small distances by diffusion, active transport accompanied by cytoplasmic streaming. Long distance transport is done by vascular system constituting xylem and phloem. This method of long distance transport is called as translocation.
The water and minerals in plants with roots travel through xylem in one direction that is from roots to stem and leaves. The organic substances and mineral nutrients travel in both the directions. The organic substances that are synthesized in the leaves will be transported to all other parts of the plant body along with the storage parts. The minerals are taken up by the roots from the soil and are transported to the leaves, stems and other parts of the plant. If any part of the plant is dead then the transported nutrients to those parts will be taken back and redirected to the growing regions of the plant. Apart from the transport of water, minerals and organic nutrients, plants also transport growth regulators, hormones and chemical stimuli.