Answer:
The phloem is responsible for transporting food from leaves to other parts of the plant.
The transport of pholem is bidirectional and changes the movement of particles according to the season. Generally, the transportation occurs in the direction of the source to sink but in spring season the direction is opposite that is from sink to source because the source and sink are n opposite sides. So in spring season, the stem tubers are sources and the growing leaves are sinks.