B4b Transpiration & Translocation

Not 'tissues and organs in plants', not 'RP investigating water loss in a leaf'

Transpiration is the movement of ___

water

translocation is the movement of

nutrients: glucose and amino acids

Transpiration occurs through

xylem tissue

translocation occurs through

phloem tissue

Xylem tissue is..

Phloem tissue is…

one/two way

Xylem tissue is one way

Phloem tissue is two way

xylem tissue is made of

xylem tissue is made of dead cells

phloem tissue is made of

phloem tissue is made of living cells

in xylem tissue, the cell wall is made of

in xylem tissue, the cell wall is made of lignin, which makes it stronger

in phloem tissue, the cell wall is made of

in phloem tissue, the cell wall is made of cellulose

in xylem tissue, cell end walls are 

in xylem tissue, cell end walls are hollow

in phloem tissue, cell end walls have

in phloem tissue, cell end walls have sieve plates, aka perforations

In translocation, substances are moved through the phloem tissue through which type of transport?

In translocation, substances are moved through the phloem tissue through Active transport

in transpiration, what direction does the water move in?

it is sucked up towards the leaves, from the roots

How does water escape the plant?

The stomata in the leaf need to open to let CO2 in, and water escapes while this happens. The plant has no interest in losing water!

the water then evaporates.

Which 4 conditions affect transpiration?

• Temperature

• Air movement / windiness

• Humidity

• Light intensity

Higher temperature = higher or lower rate of transpiration

higher temp = faster transpiration

more wind = higher or lower rate of transpiration

Windier = faster transpiration

More humid = higher or lower rate of transpiration

More humid = slower transpiration

Because it’s already wet outside the plant, so there is a lower concentration gradient so the plant tries less hard to get water out into the air.

Bright light = higher or lower rate of transpiration

more light = faster transpiration

What can we use to measure rate of transpiration?

The humble potometer

How do we use it?

And how is it reset?

as plant uptakes water, air bubble moves to the left. after a set time, see how far it has moved.

to reset the experiment, open the tap on the reservoir to allow water to flow in the other direction, pushing the bubble back towards the beaker.

4marker: Explain how water from the soil reaches the leaves. Include:

• concentration gradient

• transpiration

• osmosis

• root hair cells

• evaporation

• stomata

see folder, booklet B4b, page 10