Robert Emerson (November 4, 1903 – February 4, 1959) was an American scientist noted for his discovery that plants have two distinct

photosynthetic reaction centre A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or t ...

Family

Emerson was born in 1903 in

New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the U ...

, the son of Dr. Haven Emerson, Health Commissioner of New York City, and Grace Parrish Emerson, the sister of

Maxfield Parrish Maxfield Parrish (July 25, 1870 – March 30, 1966) was an American painter and illustrator active in the first half of the 20th century. He is known for his distinctive saturated hues and idealized neo-classical imagery. His career spann ...

. Emerson was the brother of

John Haven Emerson John Haven Emerson (February 5, 1906 – February 4, 1997) was an American inventor of biomedical devices, specializing in respiratory equipment. He is perhaps best remembered for his work in improving the iron lung. Early life Emerson was born in ...

the inventor of the

iron lung An iron lung is a type of negative pressure ventilator (NPV), a mechanical respirator which encloses most of a person's body, and varies the air pressure in the enclosed space, to stimulate breathing.Shneerson, Dr. John M., Newmarket General ...

. He married Claire Garrison, and they had three sons, and a daughter.

Career

Emerson received a master's degree in 1929 from Harvard, and received his doctorate from the

University of Berlin The Humboldt University of Berlin (german: link=no, Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany. The university was established by Frederick Will ...

working in the laboratory of

Otto Warburg Otto Warburg may refer to: * Otto Warburg (botanist) (1859–1938), German botanist * Otto Heinrich Warburg (1883–1970), German physiologist {{Hndis, Warburg, Otto ...

Thomas Hunt Morgan Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role tha ...

invited him to join the Biology Division at the

California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

where he worked from 1930 to 1937, and again for a year in 1941 and 1945. From 1942 to 1945 he worked on producing rubber from the guayule shrub for the American Rubber Company. In 1947 he moved to the Botany Department of the

University of Illinois The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the Unive ...

, where he remained for the rest of his life.

Experimental results

Emerson's first "important" result was the quantification of the ratio of

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to ...

molecules to oxygen molecules produced by photosynthesis. Emerson and William Arnold found that "the yield per flash reached a maximum when just 1 out of 2500 chlorophylls absorbed a quantum". Next, in 1939, Emerson demonstrated that between 8 and 12 quanta of light were needed to produce one molecule of oxygen. These results were controversial, as they contradicted Warburg who reported 4, then 3, and finally 2 quanta. This dispute was settled after the death of both men, and it is now agreed that Emerson was correct, and the accepted modern value is 8 – 10 quanta. In 1957, Emerson reported results that are now called the

Emerson effect The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength 680 nm (deep red spectrum) and more than 680 nm (far red spectrum). When simultaneously exposed to light of both wavelengt ...

, the excess rate of

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

after

chloroplasts A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it i ...

are simultaneously exposed to light of wavelength 670 nm (red light), and 700 nm (far red light).Emerson, R. (1958) "Yield of photosynthesis from simultaneous illumination with pairs of wavelengths",

Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...

. Vol. 127. No. 3305,

American Association for the Advancement of Science The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsi ...

These results were later shown to be the first experimental demonstration that there are two

s in plants.

Death

Emerson died in the crash of

American Airlines Flight 320 American Airlines Flight 320 was a scheduled flight between Chicago Midway International Airport and New York City's LaGuardia Airport. On February 3, 1959, the Lockheed L-188 Electra performing the flight crashed into the East River during its d ...

in New York City in 1959.

References

{{DEFAULTSORT:Emerson, Robert 1903 births 1959 deaths Accidental deaths in New York (state) American botanists California Institute of Technology faculty Harvard University alumni Researchers of photosynthesis Scientists from New York City University of Illinois faculty Victims of aviation accidents or incidents in 1959 Victims of aviation accidents or incidents in the United States