Which tissue in plants help in organic translocation?

The tissue in plants that helps in organic translocation is the Phloem. Here are the steps explaining how it works:

1. Phloem is a complex tissue of a plant which was first introduced by a scientist named Nageli in the year 1858. It is a part of the vascular system in a plant cell which involves the translocation of organic molecules from the leaves to the different parts of plants like stem, flowers, fruits and roots.

2. The process of translocation in phloem involves the movement of food materials from leaves to other parts of the plant. This process is also known as 'Source to Sink' movement, where the source is the leaves (where food is prepared by photosynthesis) and sink is the part of the plant where the food is required or stored.

3. The cells in the phloem tissue are of several types: sieve elements, companion cells, phloem fibres and phloem parenchyma. The most important of these for translocation are the sieve elements. These are elongated, thin-walled cells, which are arranged end to end to form a continuous tube. They have a perforated sieve plate between them which allows the movement of food materials.

4. The organic substance that is mainly transported by the phloem is sucrose, a type of sugar. This is produced in the leaves during photosynthesis, and is needed in all parts of the plant for energy and for the synthesis of other organic molecules.

5. The movement of sucrose and other substances in the phloem is driven by a process called 'bulk flow' or 'mass flow'. This involves the active transport of sucrose into the phloem tissue, which causes water to move into the tissue by osmosis, creating a pressure difference that drives the flow of substances along the phloem.

6. The process of translocation in the phloem is a complex one, involving a number of different processes and mechanisms. However, it is essential for the growth and development of the plant, as it ensures that all parts of the plant receive the nutrients they need.