Historical Events in Photosynthesis

Historical Events in Photosynthesis

•             Van Helmont (1648) – Increase in organic substances comes from water alone by growing a Willow tree that gains weight but soil loses only 2 ounces of the original weight.

•             Stephen Hales (1727) – Father of Plant Physiology, Plants obtain nourishment from air and light.

•             Joseph Priestley (1772) – Performed experiments with candle, mice and Mint plant and concluded that vegetation purifies the air.

•             Jean-Ingen-Housz (1779) – Confirmed Priestley’s experiment that oxygen released by the plants is possible only in light.

•             Lavoisier (1783) – Purifying gas produced by plants in sunlight is Oxygen (Phlogiston) and noxious gas produced by burning of candle (de Phlogiston) is Carbon di oxide.

•             Desaussure (1804)- Explained the importance of water in the process of photosynthesis.

•             Dutrochet (1837) – Explained the importance of Chlorophyll in Photosynthesis.

•             Von Mayer (1845) – Green plants convert solar energy into chemical energy of organic matter.

•               Liebig (1845) – Organic matter of plants was derived from CO₂.

•               Julius Von Sachs (1854) – Discovered that product of photosynthesis was starch. Green substance (chlorophyll) is located in special structures (Chloroplast).

•               T.W. Engelmann (1888)- Plotted action­ spectrum of photosynthesis

•               Blackman (1905) – Proposed Law of Limiting factors.

•               Warburg (1920) – Used unicellular green algae Chlorella for the study of Photosynthesis.

•               Van Neil (1931) – Oxygen released during photolysis comes from water and not from CO₂. He also conducted experiments in Purple green bacteria and demonstrated Photosynthesis.

In Green Sulphur bacteria H₂S is the Hydrogen donor which releases Sulphur instead of oxygen.

·              Emerson and Arnold (1932) – Existence of light and dark reaction by flashing light experiments.

·              R. Hill (1937) – Explained photolysis with the help of isolated chloroplasts and electron acceptors in the presence of light.

·              Ruben and Kamen (1941) – Used ¹⁸O radioactive Oxygen to prove that oxygen evolves from water.

·              Arnon, Allen and Whatley (1954) – Used radioactive ¹⁴CO₂ to show fixation of CO₂ by isolated chloroplast.

·            Melvin Calvin (1954) – Used radioactive ¹⁴CO₂ and traced path of carbon in the dark phase of photosynthesis or C₃ Cycle.

·            Emerson et al., (1957) – Reported existence of two photosystems

·            Hatch and Slack (1965) – Reported C₄ pathway and CO₂ fixation in C₄ plants

·              Huber, Michel and Dissenhofer (1985) – Crystalized photosynthetic reaction centre of Rhodobacter and received the Nobel Prize in 1988.