Respuesta :
Both Van Helmont and Calvin contributed to the understanding of photosynthesis. Van Helmont concluded that trees gain most of their mass from water. Calvin, on the other hand, traced the chemical path that carbon follows to form glucose. These reactions are named the Calvin Cycle which is also known as Light-independent reaction and "Dark Reactions".
Water is a element that is continuously circulated in the biosphere. Van Helmont conducted an experiment on trees. He weighed a willow tree of 5 pounds and placed it in a earthern pot containing 200 pounds of soil. Over five years, he only added distilled water and rain water to the pot and weighed the tree showing a weight of 169 pounds and while the soil had lost few ounces of weight. This concluded that the tree grew up using water alone as he was unaware of photosynthesis.
Melvin Calvin discovered the important process of photosynthesis called the Calvin cycle or the light-independent reaction. In this cycle, the carbon atoms from the carbon dioxide are fixed and used to build the three carbon sugars in association with the ATP and NADPH produced in the light reaction of the photosynthesis. Thus, proving that photosynthesis is the source of nutrition to the plants and responsible for the growth of the plants.