What is primarily transported by phloem in plants?

Phloem is primarily responsible for the transport of food, particularly in the form of sugars, throughout the plant. This process is crucial for distributing the energy produced during photosynthesis from the leaves, where it occurs, to various parts of the plant, including the roots, stems, and developing fruits.

The sugars typically transported by the phloem are primarily sucrose, which serves as a vital energy source for growth and metabolic activities in plant cells. The movement of these sugars through the phloem occurs through a process known as translocation, which relies on a pressure flow mechanism that allows for effective distribution in response to the plant's needs.

While other substances like carbon dioxide, water, and mineral nutrients play significant roles in a plant's growth and development, they are not primarily transported by phloem. For example, carbon dioxide is absorbed from the atmosphere primarily through stomata and used in photosynthesis, while water is transported through xylem. Mineral nutrients are also carried through the xylem from the soil. Thus, the phloem's main function remains the efficient distribution of the sugars produced from photosynthesis.