The mechanism of water movement through a plant
Use the words and phrases in the list to complete the paragraphs below. You
may use each word or phrase once, more than once or not at all.
active transport
oxygen concentration
transpiration pull
water potential
xylem vessels /
adhesion
mass flow
transpiration'
gradient
perspiration
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Water moves up through a plant as the result of..... Transpiration...... which is
the loss of water vapour through the Stomata...... in the leaves. This
produces a tension, called transpiration pull., which pulls columns of water
up through the ...............
...............
As water vapour is lost from the leaves, this reduces the......ter putentia /
Mesupull
inside the air spaces in the leaf........
layers. This causes water
to evaporate from the cell.
of the mesophyll cells. This
the water potential inside the mesophyll cells, producing
a water potential.
from the xylem vessels in the leaf into
the cells. Water therefore moves out of the xylem vessels, into the mesophyll
Vis
cells. It moves into these cells by
cohesion
membranes
reduces
walls
****
*******
cuticle
mesophyll
stomata
osmosis
*********
*********** ********** This removal of water from the upper parts of the xylem vessels causes the water potential at their tops to be lower than the water potential at their bases.
Water is therefore drawn up through the xylem vessels in a continuous column.
It moves by .......
The column remains continuous because water molecules are attracted to each
other by
....,and to the walls of the xylem vessels by