Photosynthesis that a complex of reactions consisting of an intermediate to cytochrome b (now a plastoquinone), another is from cytochrome f to a step in the carbohydrate-generating mechanisms. These are linked by plastoquinone, which does require energy to reduce cytochrome f for it is a sufficient reductant. Further experiments to prove that the oxygen developed during the photosynthesis of green plants came from water, were performed by Hill in 1937 and 1939. He showed that isolated chloroplasts give off oxygen in the presence of unnatural reducing agents like iron oxalate, ferricyanide or benzoquinone after exposure to light. The Hill reaction is
Photosynthesis water, and the availability of suitable temperatures for carrying out photosynthesis. The process of photosynthesis provides the main input of free energy into the biosphere, and is one of four main ways in which radiation is important for plant life. The radiation climate within plant communities is extremely variable, with both time and space. In the early 20th century, Frederick Blackman and Gabrielle Matthaei investigated the effects of light intensity (irradiance) and temperature on the rate of carbon assimilation. These two experiments illustrate several important points: First, it is known that, in general, photochemical reactions are not affected by temperature.