Investigating the Rate of Transpiration in a Mesophyte Plant Experiment to investigate the relationship between the number of
stomatal pores on the upper and the lower surfacesof the leaves of a
mesophyte plant and the rate of transpiration from those surfaces.
The aim of the experiment
The aim of the experiment is to investigate how the number of stomatal
pores is related to the rate at which water is lost from the leaves. A
mesophyte plant is chosen and the comparison is between the upper and
the lower surfaces of its leaves.
Taking into account the relative background scientific Information, it
is expected to be proven that the rate of transpiration from a leaf of
a plant is proportional to the number of stomatal pores on the surface
of that leaf.
Negative results would be to establish that the transpiration rate is
proportional to the number of stomatal pores or is not affected by it
Water is the universal solvent for a huge amount of chemical
substances in all living organisms. Plants require water for many
different reasons. It is used to uptake inorganic minerals from the
ground, to transport nutrients such as amino acids and carbohydrates
along their stems and to control their temperature. Water plays a very
significant role in the life cycle of plants being a vital assumption
for their life.
Plants take up water by the younger parts of the roots. Water then
moves across the cortex of the root towards the central tissues via
apoplast, symplast or vacuolar pathways. Whichever the root is, it
finally enters the xylem tubes and is transported upwards to end up in
leaves from where it evaporates.
This movement takes place at various rates at different parts of the
and different seasons of the year. It is maintained by and hence
dependent on the difference of the water potential between the soil
and the atmosphere. Water evaporates from the leaves creating a water
potential difference between the leaves and the stem which draws water
upwards. By the same way water is drawn from the soil into the roots
and from the roots into the stems.
The above mentioned evaporation of water through the leaves of a
plant is referred to as transpiration. It is easy to see that the rate
of transpiration is very important in respect to the movement of water
inside the plant since it triggers the establishment of the water
potential difference. Water is also lost from the lenticles of the
stems but in the leaves this takes place to a much greater extent.
The rate of transpiration is affected by several environmental
The difference of the water...