Jean Senebier

Jean Senebier (6 or 25 May 1742 – 22 July 1809) was a Genevan Calvinist pastor and naturalist. He was chief librarian of the Republic of Geneva. A pioneer in the field of photosynthesis research, he provided extensive evidence that plants consume carbon dioxide and produced oxygen. He also showed a link between the amount of carbon dioxide available and the amount of oxygen produced and determined that photosynthesis took place at the parenchyma, the green fleshy part of the leaf. Biography Senebier was born in Geneva, the son of a wealthy merchant. He wrote extensively on plant physiology and was one of the major early pioneers of photosynthesis research. Senebier also published on the experimental method, first in 1775, and then in an expanded work, in 1802. His precise definition of the experimental method anticipated the work of noted French physiologist Claude Bernard fifty years later. Senebier also served as chief librarian of the Republic of Geneva. Senebier was greatly influenced by Swiss naturalist Charles Bonnet. Senebier was also influenced by the Italian animal physiologist and experimental biologist Lazzaro Spallanzani, several of whose works Senebier translated from Italian into French. Spallanzani's chemical research on bodily functions of animals helped lead Senebier towards studying plant chemistry. Although Senebier's first research on plants was a large study on effects of light, he is remembered mainly for the extensive evidence he provided that carbon dioxide ("fixed air" or "carbonic acid," in the terminology of his day) is consumed by plants in the production of oxygen ("dephlogisticated air"), in the physiological process that later became known as photosynthesis. Senebier also found that the amount of oxygen produced is roughly proportional to the amount of carbon dioxide available to the plant. Further, he determined that the green fleshy parts of leaves (the parenchyma) are the sites where carbon dioxide is transformed into oxygen. Senebier also correctly concluded that plants use the carbon in carbon dioxide as a nutriment.