No heart, no blood and no circulation, but plants do need a transport system to move food, water and minerals around. They use two different systems – xylem moves water and solutes from the roots to the leaves – phloem moves food substances from leaves to the rest of the plant. Both of these systems are rows of cells that make continuous tubes running the full length of the plant.
Xylem cells have extra reinforcement in their cell walls, and this helps to support the weight of the plant. For this reason, the transport systems are arranged differently in root and stem – in the root it has to resist forces that could pull the plant out of the ground. In the stem it has to resist compression and bending forces caused by the weight of the plant and the wind.
|Tissue||Process||What is moved||Structure|
|Xylem||Transpiration||Moves water and minerals from roots to leaves||Columns of hollow, dead reinforced cells|
|Phloem||Translocation||Moves food substances from leaves to rest of plant||Columns of living cells|