Factors Affecting

Photosynthesis

Group 4

Photosynthesis

Photosynthesis is a physiological process.

However, the rate of photosynthesis is affected by a few factors.

The Factors Affecting the Rate of Photosynthesis

Concentration of Carbon Dioxide (CO2)

Light Intensity

Temperature

Water

Concentration of

Carbon Dioxide

In the synthesis of glucose, carbon dioxide is needed in the dark reaction as raw material.

If there is no other factor limiting the photosynthesis, an increase in the concentration of carbon dioxide gas will cause an increase in the rate of photosynthesis.

If temperature and light intensity are constant, increase in concentration of carbon dioxide will increase the rate of photosynthesis until a certain level and the rate of photosynthesis will not increase anymore.

This is because light intensity becomes the limiting factors.

The Effect of CO2 Concentration on the Rate of Photosynthesis

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Carbon Dioxide Concentration

Increase constantly

Did not increase

Light Intensity

Light is needed during light reaction of photosynthesis ( photolysis of water).

If the concentration of carbon dioxide and temperature are controlled, increase in light intensity will increase the rate of photosynthesis until it reaches a certain point.

After this point, the rate of photosynthesis will not increase anymore.

This is because other factors such as concentration of carbon dioxide become the limiting factor.

The rate of photosynthesis can be increased by increasing the concentration of carbon dioxide.

At a very high light intensities, the rate of photosynthesis can be slows down because the pigment chlorophyll is damaged by ultraviolet.

The Effect of Light Intensity on the Rate of

Photosynthesis

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Light Intensity

0.08% carbon dioxide

0.04% carbondioxide

Water

Water is required for photosynthesis.

However, it is rarely a limiting factor in photosynthesis. This is because water is needed in a very small amount in photosynthesis.

If water is not supplied, wilting will occurs and this results in the closing of stomata.

This prevents the diffusion of CO2 into the leaves. Therefore, the rate of photosynthesis decreases because of the lower of concentration of CO2 which become the limiting factor.

Temperature

The dark reaction of photosynthesis is catalysed by the photosynthetic enzymes ad, therefore, the rate of photosynthesis will affect by the changes in temperature.

The rate of photosynthesis increases when the temperature increases.( Every 10oC doubled the rate of photosynthesis.)

When the temperature is too high, the rate of photosynthesis decreases and finally stops altogether. This is because the photosynthetic enzymes denatured at high temperature.

The Effect of Temperature on the Rate of Photosynthesis

5 10 15 20 25 30 35 40 45Temperature (oC)

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