Plant Photosynthesis

In the process of photosynthesis, the carbohydrates are synthesized from CO2 and H20 in the presence of sunlight and chlorophyll and O2 is released. Source of liberated oxygen in the process of photosynthesis is water and not carbon dioxide (Ruben and Kamen, 1957).

They used isotopes of oxygen in water, i.e. H218O instead of H2O (normal) and noticed that liberated oxygen contains 18O of water and not CO2. The overall reaction can be given as under:

6CO₂ + 12H₂O ——>C₆H₁₂O₆ + 6¹⁸O₂ + 6H₂O

The fate of different molecules can be summarized as follows:

The leaves are oriented in such a manner that the sunlight intensity is effectively received at a level when photosynthesis becomes most efficient. A major amount of incident light, about 80 per cent is absorbed, 10 per cent is reflected and 10 per cent is transmitted.