Transport of Water & Mineral Ions Flashcards
All 6 cards in this deck
What is transpiration?
The loss of water vapour from a plant by evaporation from the leaves, which then diffuses out through the stomata.
What are the steps in the transpiration stream, from soil to the air outside a leaf?
e.g. water moving through a leafy plant on a warm day- Water is absorbed into root hair cells by osmosis.
- It moves up the xylem as a continuous column (the transpiration stream).
- It evaporates from the leaf cells and diffuses out of the stomata.
What is the function of the guard cells around a stoma?
They open and close the stoma, controlling water loss by transpiration and the exchange of gases.
True or false? Water is pushed up the xylem by the roots using energy from respiration.
False. Evaporation of water from the leaves pulls the column of water up the xylem; no energy from the plant is needed.
How are nitrate ions taken up from the soil into root hair cells?
By active transport, against the concentration gradient, using energy from respiration.
True or false? Most of the water vapour lost from a leaf escapes through the stomata.
True. Guard cells open and close the stomata, so they control how much water vapour is lost.