Which tissue transports water from roots to leaves?

Which tissue transports water from roots to leaves?

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

Answer: (C)

Water moving from roots to leaves happens mainly through the xylem. Xylem is a vascular tissue made of hollow, lignified cells (like vessel elements and tracheids) that form continuous tubes from the roots up to the leaves. When leaves transpire, they create a negative pressure that pulls water upward through these tubes. The water column is kept intact by cohesion between water molecules and adhesion to the walls of the xylem, a mechanism known as the cohesion-tension theory. Roots absorb water from the soil by osmosis, creating the gradient that drives water into the plant and up through the xylem. The endodermis helps regulate entry into this transport pathway, but the actual long-distance transport from roots to leaves is carried by the xylem. Phloem transports sugars and other organic nutrients, not the primary water supply, which is why the xylem is the correct tissue for this function.

Water moving from roots to leaves happens mainly through the xylem. Xylem is a vascular tissue made of hollow, lignified cells (like vessel elements and tracheids) that form continuous tubes from the roots up to the leaves. When leaves transpire, they create a negative pressure that pulls water upward through these tubes. The water column is kept intact by cohesion between water molecules and adhesion to the walls of the xylem, a mechanism known as the cohesion-tension theory. Roots absorb water from the soil by osmosis, creating the gradient that drives water into the plant and up through the xylem. The endodermis helps regulate entry into this transport pathway, but the actual long-distance transport from roots to leaves is carried by the xylem. Phloem transports sugars and other organic nutrients, not the primary water supply, which is why the xylem is the correct tissue for this function.