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Photodissociation. Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons. It is defined as the interaction of one or more photons with one target molecule that dissociates into two fragments.
The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans ), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weather features such as clouds and hazes ), all retained by Earth's gravity.
Nitrogen-fixing bacteria are capable of metabolising N 2 into the form of ammonia or related nitrogenous compounds in a process called nitrogen fixation. Both ammonium and nitrate can be immobilized by their incorporation into microbial living cells, where it is temporarily sequestered in the form of amino acids and proteins .
Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. [1]A germination rate experiment. Plant physiologists study fundamental processes of plants, such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed ...
Ionized-air glow. Nitrogen glow. Oxygen glow. Electrical discharge in air. Particle beam from a cyclotron. Ionized-air glow is the luminescent emission of characteristic blue–purple–violet light, often of a color called electric blue, by air subjected to an energy flux either directly or indirectly from solar radiation. [ 1]
The macronutrients are taken-up in larger quantities; hydrogen, oxygen, nitrogen and carbon contribute to over 95% of a plant's entire biomass on a dry matter weight basis. Micronutrients are present in plant tissue in quantities measured in parts per million, ranging from 0.1 [3] to 200 ppm, or less than 0.02% dry weight. [4]
Nitrogen assimilation. Nitrogen assimilation is the formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds present in the environment. Organisms like plants, fungi and certain bacteria that can fix nitrogen gas (N 2) depend on the ability to assimilate nitrate or ammonia for their needs.
There are biogeochemical cycles for the elements calcium, carbon, hydrogen, mercury, nitrogen, oxygen, phosphorus, selenium, and sulfur; molecular cycles for water and silica; macroscopic cycles such as the rock cycle; as well as human-induced cycles for synthetic compounds such as polychlorinated biphenyl (PCB). In some cycles there are ...