On May 6, 1742, Swiss pastor and naturalist Jean Senebier was born. Senebier wrote extensively on plant physiology and was one of the major early pioneers of photosynthesis research. He was the first who demonstrated that green plants consume carbon dioxide and release oxygen under the influence of light.
Before Jean Senebier researched in the field of photosynthesis, other scientists had engaged in the field including Jan van Helmont, who measured the mass of the soil used by a plant and the mass of the plant as it grew in the 17th century. He noticed that the soil mass changed very little and hypothesized that the mass of the growing plant must come from the water, the only substance he added to the potted plant. Helmont’s hypothesis was partially accurate. Much of the gained mass also comes from carbon dioxide as well as water, however, this was a signaling point to the idea that the bulk of a plant’s biomass comes from the inputs of photosynthesis, not the soil itself. Later, Joseph Priestley discovered that when he isolated a volume of air under an inverted jar, and burned a candle in it, the candle would burn out very quickly, much before it ran out of wax. Priestley further found out that a mouse could similarly “injure” air. He then showed that the air that had been “injured” by the candle and the mouse could be restored by a plant.
Jan Ingenhousz replicated Priestley’s experiments in 1778. He found that it was actually the sunlight hitting the plant that made it possible to revive the mouse. Jean Senebier did his most important experiments on photosynthesis during the 1790s.
Jean Senebier’s early work was influenced by the naturalist Charles Bonnet as well as by the physiologist and experimental biologist Lazzaro Spallanzani. Especially Spallanzani’s chemical research on bodily functions of animals supported Senebier’s efforts in plant chemistry. Senebier extensivly studied the effects of light on plants. However, the scientist is mostly remembered for the evidence he provided that carbon dioxide – back then named carbonic acid or fixed air – is consumed by plants in the production of oxygen. A physiological process that later became known as photosynthesis.
Senebier further discovered that the the amount of oxygen produced is roughly proportional to the amount of carbon dioxide available to the plant and Senebier that carbon dioxide is transformed into oxygen in the parenchyma. The scientist made the correct conclusion that plants use the carbon in carbon dioxide as a nutriment. Jean Senebier based his achievement that plants take up atmospheric carbon dioxide and give off oxygen completely on the phlogiston theory of chemistry. Later on, he reforfulated his findings in terms of oxygen chemistry developed by Antoine Lavoisier and colleagues.
At yovisto, you may be interested in a video lecture on Photosynthesis by Paul Andersen.
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