Transport System in Plants Flashcards
How does water move up the roots?
Water is pulled up the xylem and therefore away from the roots. This means there will be a low concentration of water in the roots. Therefore water moves into the roots (low concentration of water) from the soil (high concentration of water) via osmosis.
How does water move up the xylem?
As the water molecules travel in each xylem cell, they pull the next molecule of water behind them to the surface. These molecules pull on the molecules behind them which causes all the water molecules to be pulled up the plant
How does transpiration happen in leaves?
Water arrives in the leaf and evaporates from the cells in the spongy mesophyll layer. This causes water vapor to accumulate in the air spaces. The water vapor diffuses from the air spaces in the leaf (high concentration) to the air outside the leaf (low concentration).
How does light affect the rate of transpiration?
In bright light, plants open their stomata more, letting more water escape.
How does heat affect the rate of transpiration?
When it’s hot, water evaporates faster, so plants lose water more quickly.
How does air affect the rate of transpiration?
In humid air, there’s already a lot of moisture, so water doesn’t leave the plant as easily
How does wind affect the rate of transpiration?
Wind helps water evaporate faster by blowing away the moisture around the leaves
Explain why roots need to use the two different methods to absorb water and ions
Solution in the soil is more dilute so water moves from the dilute to the more concentrated region. The concentration of ions in the soil is less so energy is needed to move the ions.
Transpiration stream
Movement of water from the roots via xylem to the leaves
Translocation
The movement of dissolved sugars from the leaves to the rest of the plant
