Dutrochet, (Rene Joachim) Henri (1776-1847)

French physiologist who outlined the process of osmosis (the passive diffusion of water from high concentration to low concentration through a semi-permeable membrane, such as a cell wall) in plants and described various important parts of the plant respiratory mechanism. He was also the first to recognize the role of the pigment chlorophyll in the conversion by plants of carbon dioxide to oxygen (photosynthesis) and to identify stomata (pores) on the surface of leaves, later recognized as important in the exchange of gases between the plant and its surroundings.

By 1835, it had been recognized that plant cells and unicellular animals had a nucleus and that plant cells had cell walls. Little attention, however, had been paid to the material that lies between the nucleus and the membrane. Dutrochet recognized the importance of the viscous material, which we now know as protoplasm, that makes up the majority of the volume of most cells.

Dutrochet was born in Neon and graduated in medicine in Paris. He enrolled as an army physician but was forced to resign his commission after a bout of typhoid. As he was a member of a prosperous family he could afford to withdraw from public life and spent the rest of his life studying cell respiration, particularly in plants.