ACKNOWLEDGEMENT

I would like to express my special

thanks of gratitude to my teacher
MS.EMIMAL SIMON and the CBSE
BOARD who gave me the golden
opportunity to do this wonderful
project on the topic ROOT
PRESSURE , which also helped me
in doing a lot of research and has
helped me in increasing my
knowledge and skills.
TABLE OF CONTENTS

• WHAT IS ROOT PRESSURE?

• THEORY
• MATERIALS REQUIRED
• PROCEDURE
• OBSERVATION
• FACTORS AFFECTING ROOT
PRESSURE
• LIMITATIONS
• ROOT PRESSURE(POSITIVE
AND NEGATIVE)
• CONCLUSION
• BIBLIOGRAPHY
OBJECTIVE

TO STUDY AND DEMONSTRATE ROOT

PRESSURE USING BALSALM PLANT

Root ressure in plants, force that helps to

drive fluids upward iinto the water
conducting vessels(xylem). It is primarily
generated by osmotic pressure in the cells
of the roots and can demonstrated by
exudation of the fluid when the stem is cut
off just aove the ground.
What is Root Pressure?

In plants, root pressure is a force that

assists in driving fluids upward into water-
conducting channels (xylem). It is mostly
caused by osmotic pressure in the cells of
the roots and may be seen as fluid
exudation when the stem is severed
immediately above ground.

Although root pressure contributes to the

rise of water in vascular plants, it is
inadequate for the flow of sap against
gravity, especially in the tallest trees.
Furthermore, the fact that root pressures
are lowest
when water loss from leaves (transpiration)
is highest, which is precisely when plants
require the most water, indicates that root
pressure is not driving sap flow.
 THEORY
• Priestley proposed this theory (1916).
• All plants actively absorb surplus water and
tend to build up a positive hydrostatic
pressure inside the root system, which is
known as root pressure.
• The water is forced upwards along the length
of the stem to a little height as a result of this
activity.
• The diffusion gradient causes pressure to
build up inside the xylem, which is maintained
by the activity of living cells.
• As a result, root pressure contributes
significantly to water transfer.
• INTRODUCTION
Root pressure, in plants force that helps to
drive fluids upward into the water-
conducting vessels (xylem). It is primarily
generated by osmotic pressure in the cells
of the roots and can be demonstrated by
exudation of fluid when the stem is cut off
just aboveground.
The root pressure is partially responsible
for the rise of water in vascular plants,
though it alone is insufficient for the
movement of sap against the force
of gravity, especially within the
tallest trees. Furthermore, the fact that root
pressures tend to be lowest when water
loss from leaves transpiration is highest,
which is exactly when plants most need
water, shows that root pressure is not
driving sap movement.
Instead, the lifting force generated
by evaporation and transpiration of water
from the leaves and the cohesive and
adhesive forces of molecules in the vessels,
and possibly other factors, play
substantially greater roles in the rise of sap
in plants. See also cohesion hypothesis.
MATERIALS REQUIRED

A balsalm plant with stem cut,

measuring cylinder, knife, and
insulation tape.
PROCEDURE
> Take a well-watered organized potted plant
and slash the stem portion a few centimeters
above the ground level.
> Then join a glass tube by means of a strong
rubber tubing.
> The dimension of the glass tube should be
equal to the size of the stem.
> Pay attention while joining tube and stem
being bound strictly, water cannot breakout
from the tube.
> Now pour little water in the glass tube till the
water plane can be seen above the rubber tube.
> Spot the level of water (S1) in the tube.
> Keep your arrangement aside for some hours.
> Then observe and spot the water level (S2) in
the tube.
> The difference between S2 and S1 indicates
the level of water raised.
OBSERVATION

AS YOU CLEARLY OBSERVE THAT THE WATER

LEVEL HAS RAISED BY 0.2 CM.

AT BEGINNING THE WATER LEVEL IS AT 3CM.

DUE TO ROOT PRESSURE, THE WATER LEVEL

INCREASED BY 0.2 CM

The level of water in the syringe is now 3.2 cm

 Factors Affecting Root Pressure

The following elements affect root pressure:

1. The quantity of xylem vessels in the root

2. The soil’s water potential
3. The quantity of root hairs
4. The pace at which the roots absorb water
5. The stem’s water potential
6. The rate of transpiration

WHAT CAUSES ROOT PRESSURE TO

DEVELOP?
Due to active absorption of minerals, high
osmotic pressure is created .To reduce osmotic
pressure , water is absorbed and hence water
potential is increased inside the xylem.
Increased water potential also increases the
pressure in the xylem.
 Limitations of Root Pressure
• It is unable to move sufficient
volumes of water upward to
meet the water needs.
• It has little effect on the
circulation of water in tall trees
such as gymnosperms.
• The quantity of fluid transferred
by root pressure is insufficient
for quantifying water flow in the
xylem of many plants.
• When the water needs are high
in the summer, root pressure
appears to be absent.
• It is more common at night
when evapotranspiration is low.
• ROOT PRESSURE (POSITIVE
AND NEGATIVE)
Guttation from leaves or bleeding from
severed stems are common indicators of
positive pressure.

Root pressure can occur in fine roots,

where soil water is the source, or in
woody roots and stems, where water
stored in living cells, fibres, cell walls, and
living thing areas is the source.

Root pressure is defined as the positive

pressure that develops inside the roots of
plants as a result of the quick and
continuous absorption of nutrients from
the soil.

The development of root pressure is due

to active absorption, which is dependent
on the active buildup of materials in xylem
sap.

Typically, root pressure builds throughout

the night when absorption is highest and
transpiration is lowest.

During the day, transpiration is at its

highest. The water lost via transpiration
leads the guard cells and other epidermal
cells to become flaccid. They, in turn,
absorb water from the xylem.

This effectively causes a negative

pressure, also known as tension, within
the xylem vessels, which extends from
the surfaces of the leaves to the end of
the roots, all the way to the stem.
CONCLUSION
Although root pressure contributes to the
rise of water in vascular plants, it is
inadequate for the flow of sap against
gravity, especially in the tallest trees. The
water is forced upwards along the length
of the stem to a little height as a result of
this activity. When the temperature rises,
the rate of water vapour diffusion via the
stomata rises, as does the rate of
evaporation from the leaf surface. When
the humidity is high, the rate of water
vapour diffusion via the stomata is low, as
is the rate of evaporation from the leaf
surface. The quantity of fluid transferred
by root pressure is insufficient for
quantifying water flow When in the xylem
of many plants. the water needs are high
in the summer, root pressure appears to
be absent.
BIBLIOGRAPHY

https://www.britannica.com/scien
cehttps://unacademy.com
THANK YOU