B2 Transpiration and Translocation (page 40) Flashcards
What are Phloem Tubes for?
to transport food.
What are Phloem Tubes made of?
They are made of elongated living cells with small pores in the end walls to allow cell sap to flow through.
(elongated means to extend the lenth of/ to grown in length).
What do Phloem Tubes transport?
they transport food substances (mainly dissolved sugars) made in the leaves to the rest of the plant for immediate use (e.g. in growing regions) or for storage.
What direction to the transport go in Phloem Tubes?
Both directions.
(this process is called translocation)
What is Cell sap?
it is a liquid that’s made up of the substances being transported and water.
What are Xylem Tubes for?
to take water up.
What are Xylem Tubes made of?
they are made of dead cells joined end to end with NO en walls between them and a hole down the middle.
What material are Xylem Tubes strengthened with?
with a material called lignin.
(Lignin gives strength and support to the plant)
What do Xylem Tubes carry?
water and mineral ions from the roots to the stem and leaves.
What is the ‘transpiration stream’?
The movement of water from the roots, through the Xylem and out of the leaves.
What is Transpiration?
it is the Loss of Water from the Plant.
Transpiration is caused by what?
by the evaporation and diffusion (see page 17), of water from a plant’s surface.
Where does most transpiration happen?
at the leaves.
what happens when evaporation creates a slight shortage of water in the leaf?
more water is drawn up from the rest of the plant through the xylem vessels to replace it.
This in turn means more water is drawn up from the roots and so there’s a constant transpiration stream of water through the plant.
(look at page 19 to see how root hair cells are abdapted for taking up water).
Transpiration is just a side-effect of what?
of the way leaves are adapted for photosynthesis.
