Discovery Of Photosynthesis Biology Worksheets (Page 2 of 3) in pdf

Discovery Of Photosynthesis Biology Worksheets Page 2

that the cause of this phenomenon must be light. He further discovered that the accumulated gas re-lit a

glowing splint, suggesting that the air was full of oxygen. In the dark, however, he found that the plants

gave out less gas, but that the gas extinguished a flame, meaning that

the air lacked oxygen. Ingenhousz concluded that in light plants

produced oxygen, but in the dark they did not.

In 1796, Jean Senebier, a French pastor, showed that the

"injured" air was carbon dioxide and that it was taken up by plants

during photosynthesis. Senebier demonstrated that light is the agent

responsible for the fixation of carbon dioxide and that oxygen is

liberated only in the presence of carbon dioxide. In 1804, Saussure

repeated Van Helmont’s experiment, but carefully measured the

amounts of carbon dioxide and water that were given to the plant. He

showed that the carbon in the plants came from carbon dioxide and the

hydrogen from water. Saussure showed that the increase in mass of

the plant as it grows could not be due only to uptake of water (as van

Helmont concluded), but also to the incorporation of carbon dioxide.

These 5 scientists, though not the only to contribute to the discovery of photosynthesis, were

instrumental in discovering the major reactants and products of photosynthesis.

Their conclusions

provided the basis for all further photosynthesis studies.

Discovery of Photosynthesis TIMELINE

Year

Scientist (last name)

Contribution to Photosynthesis

Discovery Of Photosynthesis Biology Worksheets Page 2