Chapter 5 · Question 16
How are water and minerals transported in plants?
Q16
How are water and minerals transported in plants?
Answer Revealed
Direct Answer:
Water and minerals are transported from roots to leaves through xylem vessels by transpiration pull, root pressure, and capillary action.
Simple Explanation
Plants have special pipes called xylem that carry water and minerals from the roots all the way up to the leaves. As water evaporates from the leaves, it creates a pull that draws more water upward, like drinking through a straw.
Exam-Ready Structure
Water and dissolved minerals are transported in plants through the xylem tissue. The process involves: 1. Root absorption — Root hairs absorb water and minerals from the soil by osmosis and active transport. 2. Xylem vessels — These are long, continuous tubes made of dead cells with lignified walls, forming a pipeline from roots to leaves. 3. Transpiration pull — As water evaporates from leaf surfaces through stomata (transpiration), it creates a suction force (tension) in the xylem. This pulls water upward continuously in a column due to the cohesive and adhesive properties of water molecules. 4. Root pressure — At night when transpiration is low, minerals actively transported into the xylem create osmotic pressure that pushes water upward.
Key Points
- Water and minerals enter through root hairs
- Xylem vessels transport water upward
- Transpiration pull is the main driving force
- Cohesion and adhesion keep the water column continuous
Common Mistakes
- Saying phloem transports water (phloem transports food)
- Confusing root pressure with transpiration pull as the main force
Relevant Maps and Figures
Movement of Water During Transpiration
diagram
Use the transpiration diagram to explain why water moves upward from roots to leaves through xylem.
It helps distinguish transpiration pull from root pressure.
Use this tree transport diagram to explain upward movement through xylem and to contrast transpiration pull with food movement in phloem.
Answer Sources
- Figure 5.12 transpiration in a treefigure | Science | Life Processes | Water transport in xylem | Pages 17