Yes, phloem does have mitochondria, but not in all its cells.
Phloem is a vital part of a plant's vascular system, responsible for transporting sugars and other nutrients. While sieve elements, the main conducting cells of the phloem, have relatively few mitochondria, their companion cells are packed with them. These companion cells are metabolically active and provide energy to the sieve elements, which have reduced cellular machinery. The high concentration of mitochondria in companion cells is crucial for the energy-demanding process of sugar transport.
The Role of Mitochondria in Phloem Function
- Energy Production: Mitochondria are the powerhouses of the cell, generating ATP (adenosine triphosphate), the primary energy currency. In phloem, this ATP is essential for active transport mechanisms that move sugars against concentration gradients.
- Companion Cell Support: The companion cells, closely associated with sieve elements, possess numerous mitochondria to supply the energy needed for various functions, including loading and unloading sugars into and out of the sieve tubes.
The reference material states that phloem's companion cells have "lots of mitochondria" to provide energy for the phloem's function. This highlights the critical role mitochondria play, even though the sieve elements themselves have a reduced number.
