|Born||6 or 25 May 1742|
|Died||22 July 1809 67) (aged|
Geneva, Napoleonic Swiss Confederation
|Fields||plant physiology, photosynthesis|
|Influences||Lazzaro Spallanzani, Charles Bonnet, Antoine Lavoisier, Joseph Priestley, Jan Ingen-Housz|
|Influenced||Nicolas-Théodore de Saussure, Augustin Pyramus de Candolle|
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 plant consumed 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.
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. Senebier did some of his research jointly with fellow Swiss naturalist François Huber.
Senebier arrived at his best known achievement, his demonstration that plants take up atmospheric carbon dioxide and give off oxygen, based entirely on the phlogiston theory of chemistry, and only in his later worksdid he reformulate his conclusions in terms of the more modern, oxygen chemistry developed by Antoine Lavoisier and colleagues. This discovery by Senebier regarding gases ranks as one of the last of the important early discoveries in the unraveling of the fundamental chemical processes of photosynthesis. Marcello Malpighi and Nehemiah Grew, working independently in the late seventeenth century, and Stephen Hales in the early eighteenth century, had provided evidence that the atmosphere was important to plants, but further progress in understanding the role of gases in plant physiology awaited discoveries made between 1750 and 1780. In 1754, Charles Bonnet reported that leaves that were plunged in aerated water produced bubbles of gas, but he did not identify the gas. Then, in 1775, English chemist Joseph Priestley discovered oxygen (which he named "dephlogisticated air"), and, just a few years later, in 1779, Dutch physician and researcher Jan Ingenhousz demonstrated that the bubbles of gas observed by Bonnet on submerged leaves consisted of this same gas. Ingenhousz also published the first convincing evidence that leaves produce this gas only in sunlight.
Senebier was a close friend of noted Genevan geologist and meteorologist Horace-Bénédict de Saussure and was instrumental in the education of Horace-Bénédict's son Nicolas-Théodore de Saussure. Senebier trained the young man in Lavoisier's system of chemistry, which Nicolas-Théodore later applied in important plant-nutrition studies of his own. 180 The younger Saussure would eventually discover the role of water in photosynthesis, thus completing the early chemical research on this subject.:
In April 1809, Senebier became a Correspondent of the Royal Netherlands Academy of Arts and Sciences.
For more detailed information on Senebier, see Kottlerand Nash.
The standard botanical author abbreviation Seneb. is applied to species Senebier described.
Antoine-Laurent de Lavoisier, also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology. It is generally accepted that Lavoisier's great accomplishments in chemistry stem largely from his changing the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783), and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787) and discovered that, although matter may change its form or shape, its mass always remains the same.
Carbon dioxide is an acidic colorless gas with a density about 53% higher than that of dry air. Carbon dioxide molecules consist of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth's atmosphere as a trace gas. The current concentration is about 0.04% (412 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes, ice caps, glaciers and seawater. It is present in deposits of petroleum and natural gas. Carbon dioxide has a sharp and acidic odor and generates the taste of soda water in the mouth. However, at normally encountered concentrations it is odorless.
Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It includes ingestion, absorption, assimilation, biosynthesis, catabolism and excretion.
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 metabolic activities. This chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek phōs (φῶς), "light", and sunthesis (σύνθεσις), "putting together". In most cases, oxygen is also released as a waste product. Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth.
The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs; in mammals and reptiles these are called alveoli, and in birds they are known as atria. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.
In botany, a stoma, also called a stomate is a pore, found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the stomatal opening.
Charles Bonnet was a Genevan naturalist and philosophical writer. He is responsible for coining the term phyllotaxis to describe the arrangement of leaves on a plant. He was among the first to notice parthenogenetic reproduction in aphids and established that insects respired through their spiracles. He was among the first to use the term "evolution" in a biological context. Deaf from an early age, he also suffered from failing eyesight and had to make use of assistants in later life to help in his research.
Horace Bénédict de Saussure was a Genevan geologist, meteorologist, physicist, mountaineer and Alpine explorer, often called the founder of alpinism and modern meteorology, and considered to be the first person to build a successful solar oven.
François Huber, also known as Francis in English publications or Franz in German publications was a Swiss entomologist who specialized in honey bees. His pioneering work was recognized all across Europe and based on thorough observation with the help of several assistants due to his blindness.
Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.
Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions that allows a plant to photosynthesize during the day, but only exchange gases at night. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but they open at night to collect carbon dioxide and allow it to diffuse into the mesophyll cells. The CO
2 is stored as the four-carbon acid malic acid in vacuoles at night, and then in the daytime, the malate is transported to chloroplasts where it is converted back to CO
2, which is then used during photosynthesis. The pre-collected CO
2 is concentrated around the enzyme RuBisCO, increasing photosynthetic efficiency. This mechanism of acid metabolism was first discovered in plants of the family Crassulaceae.
Photorespiration (also known as the oxidative photosynthetic carbon cycle, or C2 photosynthesis) refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis. The desired reaction is the addition of carbon dioxide to RuBP (carboxylation), a key step in the Calvin–Benson cycle, but approximately 25% of reactions by RuBisCO instead add oxygen to RuBP (oxygenation), creating a product that cannot be used within the Calvin–Benson cycle. This process reduces the efficiency of photosynthesis, potentially reducing photosynthetic output by 25% in C3 plants. Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria.
Pierre Prévost was a Genevan philosopher and physicist. In 1791 he explained Pictet's experiment by arguing that all bodies radiate heat, no matter how hot or cold they are.
Nicolas-Théodore de Saussure was a Swiss chemist and student of plant physiology who made seminal advances in phytochemistry. He is one of the major pioneers in the study of photosynthesis.
Louis Albert Necker de Saussure HFRSE MWS FGS was a Swiss crystallographer and geographer.
Felice Fontana was an Italian physicist who discovered the water gas shift reaction in 1780. He is also credited with launching modern toxicology and investigating the human eye.
Oxygenevolution is the process of generating molecular oxygen (O2) by a chemical reaction, usually from water. Oxygen evolution from water is effected by oxygenic photosynthesis, electrolysis of water, and thermal decomposition of various oxides. The biological process supports aerobic life. When relatively pure oxygen is required industrially, it is isolated by distillation of liquified air.
Carbon dioxide is an important trace gas in Earth's atmosphere. It is an integral part of the carbon cycle, a biogeochemical cycle in which carbon is exchanged between the Earth's oceans, soil, rocks and the biosphere. Plants and other photoautotrophs use solar energy to produce carbohydrate from atmospheric carbon dioxide and water by photosynthesis. Almost all other organisms depend on carbohydrate derived from photosynthesis as their primary source of energy and carbon compounds. CO
2 absorbs and emits infrared radiation at wavelengths of 4.26 μm (2347 cm−1) and 14.99 μm (667 cm−1) and consequently is a greenhouse gas that plays a significant role in influencing Earth's surface temperature through the greenhouse effect.
Albertine Adrienne Necker de Saussure was a Genevan and then Swiss writer and educationalist, and an early advocate of education for women.
Photosynthesis systems are electronic scientific instruments designed for non-destructive measurement of photosynthetic rates in the field. Photosynthesis systems are commonly used in agronomic and environmental research, as well as studies of the global carbon cycle.
Senebier, Recherches sur l’influence de la lumière solaire pour métamorphoser l’air fixe en air pur par la végétation.