These factors are as follows:-
(1)Light:-During day time stomata remain open and so
evaporation of water takes place normally; but at night
these stomata are not open with the result transpiration is
(2)Humidity of the Air:-When atmosphere is dry, then
transpiration is more, because it receives water readily but
when atmosphere becomes moist or saturated, then it can
receive no more of water.
(3)Temperature of Air:- The rate of transpiration enhances
when the temperature surface is not allowed to become saturated.
There are four factors that affect transpiration:
Light: The presence of light allows for photosynthesis to occur in the guard cells surrounding the stomates. This decreases the Carbon dioxide levels in the cells, raising the pH. The enzymes in the cell are extremely sensitive to the pH change and with the change new enzymes are now able to function. One such enzyme is one that converts the insoluble sugar starch into Malate. Malate is soluble, raising the solute concentration in the cell, causing osmosis to occur as water flows to an area of low water concentration. This causes the guard cells to become turgid, opening the stomates, allowing transpiration to occur.
Temperature: Temperature has a positive correlation with transpiration, and it has the largest effect. As the temperature increases, the kinetic energy in the cell and the water increases. The water is able to move faster, increasing the rate of evaporation. Also, the warm air is able to absorb more water vapor, creating a steeper diffusion gradient.
Humidity: Humidity has a negative correlation with transpiration. This means that as the humidity increases, the rate of transpiration decreases. This is because as the humidity increases, the air around the stomates becomes saturated with water vapor, decreasing the concentration gradient between the air and the leaves. This means less water will evaporate into the air.
Wind: A mass flow of air removes the diffusion shell surrounding the stomates. The diffusion shell is the area around the stomate into which water has already evaporated into. This air has a higher humidity than the surrounding air and a flow of air will remove this humid air with dryer air, allowing a higher diffusion gradient.
The rate of transpiration is directly related to the degree
of stomatal opening, and to the evaporative demand of the
atmosphere surrounding the leaf. The amount of water lost by
a plant depends on its size, along with the surrounding
light intensity, temperature, humidity, and wind speed (all
of which influence evaporative demand). Soil water supply
and soil temperature can influence stomatal opening, and
thus transpiration rate.
1TEMPERATURE:when the temperature is high, transpiration
rate is increased leading to the opening of the stomata,
which now lead to the release of water to the atmosphere.
2LIGHT:the stomata only open in the day time while at night
it closes which check and control the release of water from
HUMIDITY:when the atmosphere is dry it tend to accept water
from the plant release by the stomata ,but when the
atmosphere is saturated it tend not to accept water release
by the stomata.
1.NUMBER OF STOMATA.if the leaf of the plant has a large
number of the stomata the rate of transpiration will be
high,as during stomata opening large amount of water will
evaporate to the atmosphere through stomata.
2.HUMIDITY.the areas with high humidity will experience the
low rate of transpiration as the atmosphere will contain
the high amount of water vapour