Diagram of Xylem and Phloem (with Labels) Explained
Xylem and phloem are the vascular tissues of plants that transport water and nutrients. Xylem carries water and minerals upward; phloem carries sugars and
TL;DR: Xylem and phloem are the vascular tissues of plants that transport water and nutrients. Xylem carries water and minerals upward; phloem carries sugars…
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Diagram of Xylem and Phloem (with Labels): Xylem and phloem are the vascular tissues of plants that transport water and nutrients. Xylem carries water and minerals upward; phloem carries sugars and
Diagram of Xylem and Phloem (with Labels) Explained Simply
Xylem and phloem are the vascular tissues of plants that transport water and nutrients. Xylem carries water and minerals upward; phloem carries sugars and This is a key Biology concept for 10.
Frequently Asked Questions
How does the cohesion-tension theory explain water movement in the xylem?
Water evaporates from leaf cells (transpiration), lowering water potential in leaf xylem. This creates tension (negative pressure) in the xylem. Cohesive forces (hydrogen bonding between water molecules) and adhesive forces (water sticking to xylem cell walls) allow this tension to be transmitted throughout the xylem, pulling water upward from the roots.
What is the role of companion cells in phloem transport?
Companion cells are living cells adjacent to sieve tube elements. They produce ATP via cellular respiration and use active transport to pump sugars from photosynthetic cells into sieve tubes. This lowers water potential in the sieve tube, causing water to enter osmotically, creating turgor pressure that drives phloem sap transport to sink tissues.
Why can xylem transport be unidirectional while phloem transport is bidirectional?
Xylem is dead tissue with a simple, passive transport mechanism (tension from transpiration). This creates a fixed direction (root to shoot). Phloem is alive and uses active transport controlled by source and sink regions. Sugars move from any source (producing sugars) to any sink (consuming sugars), allowing bidirectional transport based on where energy is needed.