Question

In what form does the movement of food occur in plants??

Answer 1

The movement of food within a plant differs from the movement of water. Food is produced by photosynthesis, usually in the leaves, and must then be distributed to the non-photosynthesizing parts of the plant to provide them with the necessary energy for maintenance and growth. We say that the food in the form of sugars moves from the source where it is produced to the sink where it is used. Therefore, a different type of vascular tissue is used to transport food. This tissue is called phloem, which is made of specialized cells: sieve-tube members. Unlike the cells of the xylem, these cells are still living. However, they have lost many of their organelles, including the nucleus and ribosomes, and therefore cannot make proteins. However, they have a companion cell (Figure 9.12) that has a nucleus. There is a pore between the companion cell and the sieve-tube member, so the companion cell can provide support by making proteins or carry out other cellular functions that the sieve-tube member cells cannot. The sieve-tube member cells also form a continuous column of cells, and are separated by a sieve plate through which the sugars and sap flow from one cell to another.