Who Discovered Photosynthesis?
Posted In: Science.
Photosynthesis is a process by which light energy is converted into chemical energy. Jan Baptista van Helmont, a Flemish chemist, physiologist, and physician, discovered the beginnings of photosynthesis. He was born in Brussels on January 12th, 1580, the youngest of five children. He gained a medical degree in 1599 and practiced in Antwerp at the time of the Great Plague in 1605. In 1609 he obtained his doctoral degree in medicine and married Margaret van Ranst. She was a wealthy woman whose inheritance meant that von Helmont could retire early. He continued his experiments and studies until his death on December 30th, 1644 from the effects of ingesting LSD over a long period of time.
Plants need water
In 1643, Jan Baptista Van Helmont performed a biological experiment on a willow tree in which all the ingredients were measured accurately and all changes noted meticulously. The tree was grown in a weighed pot of soil. After five years he found that the willow tree weighed about 74 kg more than it did at the start. As the weight of the soil had hardly changed, he concluded that the tree drew its nutrients from water, not the soil.
The air contains Oxygen
Joseph Priestley, a chemist, minister, natural philosopher, educator, and political theorist, was born on March 13th, 1733 in Yorkshire, England. Volume I of his book “Experiments and Observations on Different Kinds of Air” contained experimental findings that would also add to the discovery of photosynthesis. He discovered that when a candle was placed in an enclosed jar, the candle would burn out very quickly, making him the second person to discover oxygen in 1774, but the first to published it. This proves that the air contains oxygen.
Plants produce Oxygen
The next chapter in the story of photosynthesis was by Jan Ingenhousz, a Dutch physiologist, biologist and chemist. He was born on December 8th, 1730 and was court physician to an Austrian Empress. Ingenhousz discovered that small bubbles appeared from submerged plants and if the plants were then placed in the shade, these bubbles eventually stopped developing. He performed a series of experiments to prove that the bubbles produced were independent of heat and that the real cause of this phenomenon must be light. It led to his conclusion that in light, plants produced a gas called oxygen, but they didn’t in the dark.
Role of CO2 in photosynthesis
In 1796, Jean Senebier, a Swiss pastor and botanist, noted that carbon dioxide was taken up by plants during photosynthesis. He had become a staff member of the Encyclopédie Méthodique in 1787, tasked with producing a section on plant physiology. His work on the functions of oxygen and carbon dioxide in plants was published 1800, in his book Physiologie Végétale.
Connecting the dots
The last in the story of photosynthesis was Nicolas-Théodore de Saussure, a Swiss chemist and student of plant physiology who lived from October 14th, 1767 to April 18th, 1845. His addition to the process was to show that the increase in the mass of a plant as it grows could not be due only to the absorption of water, but also to the uptake of carbon dioxide. This meant that the basic reaction by which photosynthesis is used to produce food had now been outlined.
Photosynthesis and Global Warming
We now understand that plants play a very important role in the carbon cycle and global warming. During photosynthesis, the plant absorbs the carbon dioxide, uses the light energy to convert it to oxygen, which it then expels and carbon, which it uses to increases its mass. This removes carbon from the atmosphere and reduces the carbon effect on global warming.