Plant transport: xylem and phloem

A transport system from root to leaf

Roots absorb water and mineral ions. Stems support leaves and contain transport tissues. Leaves make sugars by photosynthesis. Xylem and phloem connect these organs.

Root hair cells absorb efficiently

A long root hair provides a large surface area. Water enters by osmosis through a partially permeable membrane. Mineral ions can enter by active transport against their concentration gradient, requiring energy from respiration.

Xylem: water and support

Xylem forms hollow tubes of dead cells, with no end walls blocking the pathway. Lignin strengthens the walls. Xylem carries water and mineral ions from roots to stems and leaves in the transpiration stream.

Phloem: translocation

Translocation is the movement of dissolved sugars in phloem from leaves to parts used for growth or storage. Phloem tubes are made of living cells; pores in end walls allow flow. Sugars can be carried up or down the plant, depending on where they are needed. You do not need the detailed mechanism here.

Keep the two systems clear