Which plant tissue conducts sugars downward from the leaves to other parts of the plant?

Which plant tissue conducts sugars downward from the leaves to other parts of the plant?

• A. Xylem
• B. Phloem
• C. Cortex
• D. Cambium

Answer: (B)

Sugars produced in the leaves travel through a vascular tissue specialized for transporting organic nutrients: the phloem. Phloem is made up of sieve-tube elements and companion cells that move sugars, mainly sucrose, from where photosynthesis occurs (sources) to where they are needed or stored (sinks) such as roots, growing shoots, or fruits. This movement is called translocation and can go downward or in other directions depending on where the plant needs energy. The mechanism is often described by the pressure-flow idea: loading sugars into the phloem draws in water, creating a pressure that pushes the sap toward tissues with lower pressure. Xylem, by contrast, carries water and minerals upward from the roots and does not transport sugars. The cortex is a surrounding storage/support tissue, and cambium is a growth layer that produces new xylem and phloem but isn’t the transport conduit itself. So the tissue that conducts sugars downward from the leaves to other parts is phloem.

Sugars produced in the leaves travel through a vascular tissue specialized for transporting organic nutrients: the phloem. Phloem is made up of sieve-tube elements and companion cells that move sugars, mainly sucrose, from where photosynthesis occurs (sources) to where they are needed or stored (sinks) such as roots, growing shoots, or fruits. This movement is called translocation and can go downward or in other directions depending on where the plant needs energy. The mechanism is often described by the pressure-flow idea: loading sugars into the phloem draws in water, creating a pressure that pushes the sap toward tissues with lower pressure. Xylem, by contrast, carries water and minerals upward from the roots and does not transport sugars. The cortex is a surrounding storage/support tissue, and cambium is a growth layer that produces new xylem and phloem but isn’t the transport conduit itself. So the tissue that conducts sugars downward from the leaves to other parts is phloem.