Jean Baptiste Boussingault
1864, French chemist Jean Baptiste Boussingault catalyzed the discovery of the major photosynthesis equation we know so well today, 6CO2 + 12H2O + light energy ----> C6H12O6 + 6O2 + 6H2O. This equation demonstrates how carbon dioxide, water, and light energy are utilized in the formation of the energy-rich carbohydrate glucose while also producing oxygen as a byproduct. Boussingault made this discovery by generating quantitative measurements of oxygen production and the uptake of carbon dioxide. Boussingault conducted the bulk of his research in his Agricultural Experiment Station (pictured below) in Pechelbronn in Alsace, France, which he built himself on his wife's property.
Emil Godlewski Sr.
In 1873, Nine years after Boussingault fueled the discovery of the photosynthesis equation, Emil Godlewski Sr. discovered that starch formation in illuminated leaves was correlated with the presence of carbon dioxide within the atmosphere. Godlewski was a Polish plant physiologist and agricultural chemist who centered his research efforts around photosynthesis in plants. Godlewski "piggy-backed" his research efforts off of Boussingault's research involving collecting quantitative measurements of carbon dioxide uptake, and strengthened the understanding of the relationship between the intensity of photosynthesis and the abundance of carbon dioxide. Godlewski's efforts stretched further beyond the effects of carbon dioxide on photosynthesis; He also has been accredited for making significant contributions to the areas of respiration, growth, etiolation, metabolic transformation of protein, water transport, and nitrification (Kokowski, 2006).
Godlewski earned a reputation for producing experiments driven by enormously inventive methods, strategically-planned research, as well as extensive knowledge and reliable results. Utilizing simple but clever methodology, Godlewski grew plants in the presence of light, but in the absence of carbon dioxide, thus isolating the impact of the presence of light on photosynthesis (Kokowski, 2006).
Godlewski earned a reputation for producing experiments driven by enormously inventive methods, strategically-planned research, as well as extensive knowledge and reliable results. Utilizing simple but clever methodology, Godlewski grew plants in the presence of light, but in the absence of carbon dioxide, thus isolating the impact of the presence of light on photosynthesis (Kokowski, 2006).
Charles Barnes
Prior to 1893, the reduction of carbon dioxide into organic material by plants was referred to as "assimilation." This was also the term used to describe anabolic metabolism in animals. This was until a man named Charles Barnes suggested that using the same term for these two processes was perplexing, and decided to write a paper in which he read in front of a crowd representing the Botanical Section of the American Association for the Advancement of Science in Madison, WI during the summer of 1893. In this paper, Barnes proposed two new names of the process: photosyntax and photosynthesis.
Barnes (1893) wrote: "the plant process has been called ‘assimilation’ , ‘assimilation proper’, and ‘assimilation of carbon’. I think that none of these terms is appropriate. Assimilation has long been used in animal physiology to des- ignate the appropriation of digested food by the different tissues, and its conversion into the sub- stances of those tissues. . . . For the process of formation of complex carbon compounds out of simple ones under the influence of light, I propose that the term photosyntax be used. Photosyntax is the synthesis of complex carbon compounds out of carbonic acid, in the presence of chloro- phyll, under the action of light. . . . I have care- fully considered the etymology and adaptation, as well as the expressiveness, of the word proposed, and consider it preferable to photosynthesis which naturally occurs as a substitute (emphasis added)."
Barnes (1893) wrote: "the plant process has been called ‘assimilation’ , ‘assimilation proper’, and ‘assimilation of carbon’. I think that none of these terms is appropriate. Assimilation has long been used in animal physiology to des- ignate the appropriation of digested food by the different tissues, and its conversion into the sub- stances of those tissues. . . . For the process of formation of complex carbon compounds out of simple ones under the influence of light, I propose that the term photosyntax be used. Photosyntax is the synthesis of complex carbon compounds out of carbonic acid, in the presence of chloro- phyll, under the action of light. . . . I have care- fully considered the etymology and adaptation, as well as the expressiveness, of the word proposed, and consider it preferable to photosynthesis which naturally occurs as a substitute (emphasis added)."
Frederick Frost Blackman
In 1905, a British plant physiologist named Frederick Frost Blackman introduced two types of reactions; a rapid light-dependent photochemical process and a slower temperature-dependent biochemical process. These were later named "light reactions" and "dark reactions" and demonstrated the concept of limiting factors. Soon after in 1913, Richard Willstatter and Arthur Stoll published studies on the structure and chemistry of chlorophyll. Two years later in 1915 Willstatter was awarded the Nobel Prize for his work.
Robert Hill
Twenty-Four years went by before the next significant discovery was made involving photosynthesis. In 1937, Robert (Robin) Hill demonstrated that when an artificial electron acceptor was present, isolated chloroplasts had the ability to form oxygen even in the absence of carbon dioxide. This artificial electron acceptor is named DCPIP (2, 6-Dichlorophenol-indophenol), and is known to be a very accurate tool for measuring the rates of oxygen evolution due to its ability to mimic NADP.