Transportation in Plants - Transportation of Food and Other Substances

Plants transport food made in the leaves to all parts of the plant through a process called translocation. This process moves food (like sugars) in both upward and downward directions and is carried out by a specialised tissue called a phloem.

• Food is delivered to growing regions, storage organs (roots, fruits, seeds), and other cells that need energy.
• Excess food is stored in roots, fruits, and seeds for later use by the plant or for reproduction.
• Translocation ensures that nutrients are directed where they are most needed, such as to flowers during blooming or fruits during development.
• Translocation is a highly coordinated process that helps plants effectively distribute food and maintain their growth, survival, and reproduction.

The movement of soluble products of photosynthesis from the leaves to other parts of the plant through phloem is called translocation.

• Leaves produce food through photosynthesis, and this food (mainly in the form of sucrose) is transported by the phloem to different parts of the plant, including growing regions, roots, fruits, and seeds.
• Translocation is an active process, meaning it requires energy to occur. This energy is supplied by ATP (adenosine triphosphate), the energy currency of cells.
• When sucrose is transported to a particular part of the plant, the water concentration in that area decreases.
• Water moves into these cells by diffusion (movement of water from higher to lower concentration). This increases the internal pressure in the cells, known as turgor pressure.
• The high pressure pushes the food to neighbouring cells with lower pressure, ensuring a continuous flow of nutrients.
• During the flowering season, sugars stored in roots or stems are transported to the buds. This provides the energy needed for the buds to grow and blossom into flowers.

• Food (photosynthate) is produced in leaves (source) and transported to other parts (sink) like roots, stem, and fruits; this process is called translocation of food.
• Translocation occurs through phloem tissue (sieve tubes), and food is mainly transported in the form of sucrose.
• Movement of food can be vertical (upward and downward) and lateral (from phloem to cortex or pith).
• Phloem transport is bidirectional, and food moves along the concentration gradient from source to sink.
• According to Munch’s pressure flow theory, food transport occurs due to the turgor pressure gradient created by the loading (at the source) and unloading (at the sink) of sugars.