Photosynthesis

By riddhisharma1234567890
  • 350 BCE

    c350 BC

    Aristotle proposes that plants, like animals, require food. Anticipates Priestley's work 2000 years later by asserting that plants do not require animals but animals require plants.
  • 300 BCE

    c300 BC

    Theophrastus writes that plants obtain their nourishment through the roots.
  • 1450

    1450

    Nicholas of Cusa proposes (but apparently never performs) an experiment in which a plant is weighed and then planted in a container containing a weighed amount of soil. After a period of growth, the final weights of plant and soil, as well as the total weight of water applied, are determined and compared to the initial values. He speculates this will demonstrate that the mass of the plant was derived from water rather than soil.

  • 1648

    Jean Baptiste van Helmont performs the experiment proposed by Nicholas of Cusa nearly 200 years earlier. He concludes that the entire mass of the plant came from water, but ignores a very slight decrease in the weight of the soil.

  • 1679

    Edme Mariotte proposes that plants obtain part of their nourishment from the atmosphere.

  • 1727

    Stephen Hales writes that plant leaves "very probably" take in nourishment from the air, and that light may also be involved.

  • 1754

    Charles Bonnet observes the emission of gas bubbles by a submerged illuminated leaf.

  • 1771

    Joseph Priestley finds that air which has been made "noxious" by the breathing of animals or burning of a candle can be restored by the presence of a green plant. He isolates the gas later identified as oxygen.

  • 1774

    Antoine Lavoisier begins to investigate and later names oxygen. He recognises that it is consumed in both animal respiration and combustion.

  • 1779

    Jan Ingenhousz discovers that only the green parts of plants release oxygen and that this occurs only when they are illuminated by sunlight.

  • 1782

    Jean Senebier demonstrates that green plants take in carbon dioxide from the air and emit oxygen under the influence of sunlight.

  • 1791

    Comparetti observes green granules in plant tissues, later identified as chloroplasts.

  • 1804

    Nicolas de Saussure shows that the carbon assimilated from atmospheric carbon dioxide cannot fully account for the increase in dry weight of a plant. He hypothesized that the additional weight was derived from water. At this point, therefore, the basic equation of photosynthesis was established. It was understood as a process in which a green plant illuminated by sunlight takes in carbon dioxide and water and converts them into organic material and oxygen.

  • 1818

    Pierre Joseph Pelletier and Joseph Bienaime Caventou give the name "chlorophyll" to the green pigment in plants.

  • 1837

    Rene Dutrochet makes the connection between chlorophyll and the ability of plants to assimilate carbon dioxide. Also identifies stomata on leaf surfaces.

  • 1842

    Matthias Schleiden postulates that the water molecule is split during photosynthesis.

  • 1844

    Hugo von Mohl makes detailed observations of the structure of chloroplasts.

  • 1845

    Julius Robert von Mayer proposes that the sun is the ultimate source of energy utilised by living organisms, and introduces the concept that photosynthesis is a conversion of light energy into chemical energy.

  • 1862

    Julius von Sachs demonstrates light-dependent starch formation in chloroplasts.

  • 1864

    Jean Baptiste Boussingault makes accurate quantitative measurements of carbon dioxide uptake and oxygen production, a step leading to a balanced equation for photosynthesis:
    6CO2 + 12H2O ----> C6H12O6 + 6O2 + 6H2O

  • 1873

    Emil Godlewski confirms that atmospheric carbon dioxide is the source of carbon in photosynthesis by showing that starch formation in illuminated leaves depends upon the presence of carbon dioxide.

  • 1883

    Theodor Wilhelm Engelmann illuminates a filamentous alga with light dispersed through a prism. He finds that motile aerobic bacteria congregate near the portions illuminated by red and blue wavelengths, thus producing the first action spectrum for photosynthetic oxygen evolution.

  • 1893

    Charles Barnes suggests that the process by which illuminated green plants manufacture carbon compounds be called either "photosyntax" or "photosynthesis." Although Barnes prefers the former, "photosynthesis" is adopted into common usage.

  • 1941

    Cornelis van Niel publishes a summary of his work showing that photosynthetic bacteria which use H2S as an electron donor produce elemental sulfur instead of oxygen. He suggests by analogy that the O2 released in plant photosynthesis is derived from H2O rather than CO2.

  • 1955

    Daniel Arnon demonstrates that isolated chloroplasts are capable of carrying out complete photosynthesis.