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(350B.C.) Proposed the idea that plants consume food just like animals.
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Proposed the idea that the mass of plants are derived from water instead of soil by the experiment of weighing a plant and a container filled with soil, and then weighing them again a while after the plant is planted in the soil. (Experiment was not performed)
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Performed the experiment proposed by Nicholas of Cusa. Concluded that the weight gain of the plant came from water, but ignored a slight decline of weight of soil.
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Propose the idea that plants gain part of their nutrients from the atmosphere
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Discovered that most of the water absorbed by plants are released into the atmosphere which opposed Van Helmont’s conclusion that plants gain most of their weight from water.
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Stated that plants “very probably” obtain some part of their nutrients from the air through the leaves, and that light is also absorbed.
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Discovered that green plants can restore the air polluted by burning candles or animal respiration and isolated oxygen gas.
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Investigated and named oxygen. Then identified its presence in animal respiration and combustion reactions.
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Discovered that only the green parts of plants can release oxygen when illuminated by sunlight.
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Demonstrated that green plants are able to take in CO2 (g) then transform and release it as O2 (g) under the effect of sunlight
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Hypothesized that the weight of plants derives from carbon and water. Established the basic equation of photosynthesis.
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Proposed that living organisms use the sun as energy source, and plants get energy by converting light energy into chemical energy through the process of photosynthesis
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Demonstrated the formation of starch through a light-dependent reaction in the chloroplast
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Made accurate quantitative measurement of CO2 (g)usage and O2 (g) production and established the balanced equation of photosynthesis reaction.
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Produced the first action spectrum for photosynthetic oxygen evolution by discovering that motile aerobic bacteria gather near red and blue ends of the wavelength of light through an experiment in which a filamentous algae is illuminated with light dispersed through a prism.
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Developed the law of limiting factors which determines the rate of photosynthesis reactions. Established the light-dependent and light-independent reaction.
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With coworkers, traced the pathway of C14 through a plant during photosynthesis and discovered that sunlight was stored in the chloroplast first before changing into chemical energy.
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First to discover indications of the presence of two photosystems in the light-dependent reactions of photosynthesis by describing the “red drop” and “enhancement” effects
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With the help of coworkers, identified a chlorophyll a derivative which is the primary electron acceptor of green sulfur bacteria.
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With the help of other scientists discovered that a single photon is able to excite electrons in different chromophores at the same time.
