When traveling through sieve tube elements,dissolved sugars and other substances move from sources to sinks by traveling

Question

Quizplus · Accepted Answer

Sieve tube elements are interconnected by sieve plates, which are formed of plasmodesmata. This allows for dissolved sugars and other substances to move horizontally from cell to cell, from sources (where they are produced or stored) to sinks (where they are needed for growth or metabolism). Vertical movement through the open ends of each sieve tube (A) or through phloem cells oriented adjacent to each other (C) is not the primary mechanism of transport in the phloem. Combining with xylem (D) is not possible, as the xylem and phloem are separate tissue systems with different functions. Movement from companion cells on one side to companion cells on the other side (E) is not necessary, as the companion cells are already directly connected to the sieve tube elements.

When Traveling Through Sieve Tube Elements,dissolved Sugars and Other Substances