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: -Phloem is a highly specialised vascular tissue that forms an interconnected network of continuous strands throughout a plant’s body. It transports sugars, nutrients, and a range of signalling molecules between leaves, roots, flowers, and fruits. As a result, phloem is central to plant function.

Detailed explanation-3: -As the fluid is pushed down (and up) the phloem, sugars are removed by the cortex cells of both stem and root (the “sinks") and consumed or converted into starch. Starch is insoluble and exerts no osmotic effect. Therefore, the osmotic pressure of the contents of the phloem decreases.

Detailed explanation-4: -The transport phloem has a dual function: it transports assimilates not only to terminal sinks (e.g. the roots and shoots) but also to lateral sinks along the path (e.g. the cambium) which are responsible for growth and tissue maintenance.

Detailed explanation-5: -Sucrose is delivered by the phloem to the most distant root tips and, en route to the tip, is used by the different root tissues for metabolism and storage. Besides, a certain portion of this carbon is exuded in the rhizosphere, supplied to beneficial microorganisms and diverted by parasitic microbes.