what is the location and function of companion cells
Answers
Companion cells deliver ATP, proteins and other nutrients to sieve elements. Companion cells are ground tissue cells found within the phloem of flowering plants that manage the flow of nutrients through sieve tubes.
The major functions of companion cells are as follows:
1) companion cells in the veins of leaves function in the transfer of assimilates from photosynthetic tissues and bundle sheaths into the sieve tubes.
2) Apoplastic loading, a process utilizing energy, is facilitated by carrier proteins called sucrose transporters which are located in the plasma membranes of companion cells and/or sieve tube members.
3) Companion cells that function as transfer cells are characterized by extensive wall in growths that vastly increase the surface area of the plasma membrane.
4) companion cells also play an important role in maintaining the viability and long-distance translocation system of the enucleate sieve tube members by providing them with proteins, including informational (signaling) molecules, and ribonuclear protein complexes as well as ATP.
The companion cells are usually found in the phloem area of the plants and their main function is to regulate the activities which are related to the sieve element.
Another function that these cells can perform is the maintenance of the viability in the plants.
Apart from this there are many other functions that can be performed by these companion cells as of their assistance.