Factors Affecting Photosynthesis

A plant’s yield is determined by photosynthesis. Photosynthesis as discussed earlier is a physio-chemical process. In simpler terms, it is the basic mechanism of food generation. Hence it is futile to debate its importance. Furthermore, the factors affecting photosynthesis can be separated loosely into two categories, being internal and external factors.

  • Internal factors include the structure of that particular plant, the age of the plant, the plant’s genetic make-up, growth, the orientation of leaves and so on.
  • External factors include sunlight, carbon dioxide concentration, temperature, water, and so on.

When the topic of the rate of photosynthesis is raised, the time comes into play. As wherever the word rate is used, time inadvertently becomes involved. In other words, it is the same as asking how fast does photosynthesis take place. This can be measured by determining the amount of glucose produced by a plant over a given period of time. This study is of great importance to farmers.

Factors Affecting Photosynthesis

By understanding the factors that affect photosynthesis, one can better understand the rate of the process.

  • Light: Without light, a plant cannot photosynthesize very quickly, regardless of whether there are water and CO2 or not. But overdoing light is also not a good idea. In nature, balance is crucial. But increasing the intensity of light to a prudent limit will speed up the process.
  • Carbon Dioxide: It happens to be the major limiting factor. The problem arises because the concentration of carbon dioxide in the air is less. Even if there is plenty of light, the plant cannot photosynthesize in the absence of sufficient amount of carbon dioxide.
  • Temperature: The plants are affected lesser by temperature in comparison to light and CO2. Nevertheless, if the temperature is too hot or too cold, the rate of photosynthesis is adversely affected. C4 plants have an affinity towards higher temperatures while C3 have a much lower optimum temperature.
  • Water: It makes its presence felt more through its effect on the plant rather than directly on photosynthesis. It is found that slight deficiency of water shows a considerable reduction in plant yield.

As is obvious each of these factors is interrelated and a fine balance is crucial.

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Practise This Question

Who of the following biologists was awarded 1961 Nobel prize for elucidating the sequence of dark reaction of photosynthesis?