Question

what is phloem loading and phloem unloading?

Answer 1

The below mentioned article provides an useful note on the phloem loading and unloading in plants. Translocation of organic solutes such as sucrose (i.e., photosynthetic) takes place through sieve tube elements of phloem from supply end (or source) to consumption end (or sink)

Answer 2

Answer:

This transfer of sugars (photosynthetic) from mesophyll cells to sieve tube elements in the leaf is called as phloem loading. On the other hand, the transfer of sugars (photosynthetic) from sieve tube elements to the receiver cells of consumption end (i.e., sink organs) is called as phloem unloading.