A team led by a University of Minnesota researcher has found a universal rule that regulates the metabolism of plants of all kinds and sizes and that may also offer a key to calculating their carbon dioxide emissions, a number that must be known precisely in order to construct valid models of global carbon dioxide cycling. Emissions of the gas occur in both plants and animals through the process of respiration; Peter Reich, a professor of forest resources, and his colleagues have found that plant emissions can be deduced from the nitrogen content of any plant. The study also reveals that the respiration, or metabolic, rates of plants and animals follow different laws of scaling with respect to body size. The work will be published in the Jan. 26 issue of the journal Nature.
In revealing nitrogen content as the key to plant metabolic rates, the work uncovered a fundamental difference between plants and animals in how their metabolism varies with size. The larger an animal, the slower its metabolism on a per-weight basis. Thus, although an elephant burns many more calories per hour than a mouse, the mouse has a much higher rate per pound of body weight. An elephant with the same rate per pound as a mouse would generate so much heat it would have serious problems maintaining body temperature and eating fast enough to keep up. Instead of a one-to-one ratio between body size and metabolic rate, as an animals body weight quadruples, its respiration rate only triples.
In contrast, when Reich and his colleagues studied 500 plants from 43 species, they found that within a wide range of plant sizes, a quadrupling of weight leads to a quadrupling of respiration rate. The important variable was nitrogen content: The more nitrogen in a plant, the more it respired and the more carbon dioxide the plant emitted. Similarly, if two plants were the same size but had different concentrations of nitrogen in their tissues, the one with the higher nitrogen concentration had a higher respiration rate. Conversely, a big plant and a small plant with the same total nitrogen content would put out equivalent amounts of carbon dioxide over the same time period.
Professor Peter Reich | EurekAlert!
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27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
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Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
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In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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