NEET BIOLOGY

Detailed explanation-1: -Sugars produced in sources, such as leaves, need to be delivered to growing parts of the plant via the phloem in a process called translocation, or movement of sugar. The points of sugar delivery, such as roots, young shoots, and developing seeds, are called sinks.

Detailed explanation-2: -After sugars are produced in photosynthesis, these sugars must be transported to other parts of the plant for use in the plant’s metabolism. Part of the pressure-flow theory is that the sucrose produced is moved by active transport into the companion cells of the phloem in leaf veins.

Detailed explanation-3: -The mechanism by which sugars are transported through the phloem, from sources to sinks, is called pressure flow. At the sources (usually the leaves), sugar molecules are moved into the sieve elements (phloem cells) through active transport.

Detailed explanation-4: -Phloem transports carbohydrates, produced by photosynthesis and hydrolysis of reserve compounds, to sink tissues for growth, respiration and storage. At photosynthetic tissues, carbohydrates are loaded into phloem (Rennie and Turgeon 2009), a process that raises the solute concentration.