Photosynthesis Timeline.

Process of photosynthesis with no if and but, without any doubt, will retain a position forever, among one of the most important chemical reactions occurring on the planet earth.

Let's go through historical timeline of who, how and when, great people contributed to understand exactly what happens during Photosynthesis:

• In c350BC, Aristotle proposes plants, like animals, require food.

• In c300BC, Theophrastus writes that plants gets food through their roots.

• In 1450, Nicholas of cusa he proposes an experiment which he never performed, in which the plant is weighed and then planted in the weight amount of soil in the container. Plant, soil and applied water are weighed after a period of growth. He speculated this experiment will proove that the mass gained in the plant, is only due to water and not the soil.

• In 1648, Jean Baptist Van Helmont performs the experiment originally proposed by Nicholas Cusa, 200 years earlier. The experiment was performed on willow tree, which prooved that all mass gained by the tree is due to water and not soil.

• In 1679, Edme Mariotte, proposed that plants gained part of its nourishment from atmosphere.

• In 1727, Stephen Hales, writes that the plant leaves probably takes nourishment from the air, and that light may also be involved.

• In 1754, Charles Bonnet observes the emission of bubbles by a submerged illuminated leaf.

• In 1771, Joseph Priestly in the particular experiment finds that air which is used for the breathing of animals and burning of the candle can be restored by the presence of the green plants. He isolates the gas later identified as oxygen.

• In 1774, Antoine Lavoisier finds that oxygen is the gas that supports the breathing in animals and burning of candle. And discards the theory of Phlogiston, that a hypothetical substance is released during animal respiration or combustion.

• In 1779, Jan Ingenhousz discovers that only green parts of the plants releases oxygen, only in the presence of sunlight.

• In 1782, Jean Senebier demonstrate that plant releases oxygen and inhale carbon dioxide when exposed to sunlight.

• In 1791, Comparetti witnesses green granules in plant tissues later identified as chloroplasts.

• In 1804, Nicholas de Sassure, shows that carbon assimilated from atmospheric carbon dioxide cannot fully account for the total dry mass of the plants. He hypothesized that the additional weight is due to the water and thus a basic photosynthetic reaction was established where plants when, exposed to sunlight takes in carbon dioxide realses oxygen and organic matter.

• In 1818, Pierre Joseph Pallatier and Joseph Bienaime Canventou, gave the name chlorophyll to the green pigments found in plants.

• In 1842, Mathias Schleiden postulates that the water molecule splits during photosynthesis.

• In 1844, Hugo Vohn Mohl, gives in detail observations of the structure of chloroplasts.

• In 1845, Julius Robert Von Mayer, proposes that sun is the ultimate source of energy used by all living organisms and says that photosynthesis is the conversion of light energy into chemical energy.

• In 1862, Julius Vohn Sachs, light dependent starch formation in chloroplasts.

• In 1864, Jean Baptiste Baussingault finds out exact quantity of carbon dioxide uptake and oxygen released. This paved the way to balanced equation of Photosynthesis: 6CO2 + 12H2O + light energy --------> C6H12O6 + 6O2 + 6H2O 

• In 1873, Emil Godleweski finds out that the atmospheric carbon dioxide is the source of carbon in photosynthesis by showing that starch which formed in the leaves exposed to sunlight, was dependent on the presence of carbon dioxide.

• In 1883, Theodor Wilhelm Engelmann, exposed fimantous alga to light through spectrum. He finds out that these bacterias group themselves near blue and red wavelengths, thus, witnessed a first action spectrum for Photosynthesis.

• In 1883, Arthur Meyer describes the chloroplasts grana.

• In 1893, Charles Barnes suggests that the process by which green plants when exposed to light manufacture carbon compounds, be called either 'photosyntax' or 'photosynthesis'. But in those times Charles Barnes prefers 'photosyntax'.

• In 1905, F.F.Blackman, works on and develops the concepts of limiting factors. He showed that  photosynthesis consist of two types of reaction: a rapid light-dependent photochemical process and a slower temperature-dependent biochemical process; Later came to be known as "light-reaction" and "dark-reaction" respectively.

• In 1913, Richard Wilstatter and Arthur Stoll, publish studies on the structure and chemistry of chlorophyll. And thus, in 1915, Wilstatter got the Nobel prize.

• In 1937, Robert Hill demonstrated that in presence of an artificial electron acceptor isolated chloroplasts can release oxygen in absence of carbon dioxide.

• In 1941, Cornelia Van Niel, publishes a summary of his work which shows how in presence of H2S as a electron donor, photosynthetic bacteria releases elemental sulphur. This analogy proved that the oxygen released in the photosynthesis is derived from H2O rather than CO2.

•  Samuel Ruben and Martin Kaman used a heavy isotope 18O to confirm that the oxygen released in the photosynthesis is derived from H2O.

• In 1954, Daniel Amon, shows light-dependent, ATP is produced in chloroplasts.

•  In 1955, Daniel Amon, shows isolated chloroplasts is fully capable of carrying out complete photosynthesis. 

• In 1956, Melvin Kelvin, explains the pathway of carbon assimilation in photosynthesis by the use of radioactively labeled 14CO2.

• In 1957, Robert Emerson, describes the "red drop" and "enhancements" effects, to prove that there are two separate photochemical systems involved in photosynthesis.

• In 1960, Robert Woodward, synthesizes chlorophyll, and awarded with Nobel prize in 1965.

• In 1960, Robin Hill and Fay Bendall, based on the work oh Emerson, and few others, presented "Z- Scheme" model for the photosynthetic light reactions. This model states that there are two slightly different light reactions involved in photochemical process each activated by slightly different two wavelengths of light; One oxidizes water and reduces cytochrome-f, while the other oxidizes cytochrome-f and reduces NADP.

• In 1961, Louis Duysens provides evidence for Z-Scheme model by showing how cytochrome-f switches between oxidation and reduction states when exposed to alternating wavelengths of light.

• In 1968, Roderick Clayton, isolates reaction center complexes.

• In 1970, Bessel Kok, presented "S-State" model of charge accumulation to explain the stepwise oxidation of H2O and release of O2.

• In 1984, Hans Deisenhofer, Hartmut Michel, and Robert Huber crystallizes the photosynthetic reaction center from a purple bacterium. They used X-ray diffraction technique to determine its detailed structure and thus, shared a Nobel prize in 1988.

• In 2006, Junko Yano, Vittal Yachandra, and co-workers determine the structure of manganese-calcium water.

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Information Source:

http://photobiology.info/History_Timelines/Hist-Photosyn.html