Final answer:
Sugars are produced in the mesophyll cells within plant leaves and sent to the roots or other parts of the plant via the phloem network in a process called translocation. The phloem system utilizes positive osmotic pressure to assist the movement of sugar-water mixtures to various sinks, where they are utilized or stored.
Step-by-step explanation:
When considering what happens to the sugars in a plant up to 80, the correct statement is: sugars are produced in the leaves and sent to the roots via phloem. Sugars, primarily in the form of sucrose, are synthesized during photosynthesis in the mesophyll cells of leaves. These sugars, referred to as photosynthates, must be delivered to other parts of the plant, which are growing or storing energy, known as sinks, via a process called translocation.
Using a transport system known as the phloem, the sucrose is actively transported into the sieve-tube elements and then moved throughout the plant. This movement of sucrose leads to an influx of water from the xylem to the phloem due to osmotic pressure, creating a positive pressure that assists in transporting the sugar-water mixture toward various plant parts like roots, young shoots, and developing seeds. In the roots, sugars are used for growth or converted to starch for storage.
The assertion that sugars are absorbed directly from the soil or that they are produced in the roots is incorrect. Sugars are not transported in the xylem, as this system primarily transports water and minerals from the roots to other parts of the plant in a unidirectional flow. Hence, the pattern of sugar transport in plants is critical for their growth and development, involving sophisticated mechanisms within phloem tissue.