Respiration from roots and the mycorrhizosphere
Respiration from roots and the mycorrhizosphere
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根和菌根际的呼吸作用
DOI：
10.1017/cbo9780511711794.008
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
G. Wieser
中科院分区：
文献类型：
--
作者：
F. Moyano;O. Atkin;M. Bahn;D. Bruhn;A. Burton;A. Heinemeyer;W. Kutsch;G. Wieser
全球碳循环中最大的通量是植物通过光合作用吸收CO2。在全球范围内，初级生产总值（GPP）或陆地植物吸收的CO2总量的估计值在每年约109至120 Pg C之间（Schlesinger，1997; Zhao等人，2005年）。除了作为化石燃料仍然储存在被动有机物池中的碳以及估计每年沉积在海底的0.2 Pg C之外，同化的碳最终通过植物或异养生物的呼吸作用返回大气。植物固定碳原子和将其转化为二氧化碳之间的时间变化很大，从几个小时到几千年不等。植物吸收的碳被转移到植物器官中，在那里它可以被用作结构生物量的建筑材料、储存或作为呼吸作用的基质。进入根部的碳也可以分泌或转移到共生体，如菌根真菌（Farrar，1999）。用于每种目的的同化碳的量将取决于植物的需求，这进一步由植物和环境因素决定。对许多植物物种的不同研究表明，平均每单位时间通过光合作用吸收的碳的50%被呼吸，数量在35%和80%之间（Lambers，1985; Amthor，2000 a）。其他研究表明，平均而言，光合作用产生的近一半碳水化合物转移到根部，其中约40%的碳用于呼吸（Lambers，1987; Farrar和威廉姆斯，1990）。然而，这些比例可以变化。根系呼吸的碳量
The largest flux in the global carbon cycle is the uptake of CO2 by plants as photosynthesis. Estimates of gross primary production (GPP), or total amount of CO2 assimilated by terrestrial plants, range between about 109 and 120 Pg C per year at the global scale (Schlesinger, 1997; Zhaoet al., 2005). Except for carbon that remains stored in passive organic matter pools, as fossil fuel, and an estimated 0.2 Pg C per year sedimenting on the ocean floors, assimilated carbon is eventually returned to the atmosphere by respiration, either by plants or by heterotrophic organisms. The time between the fixation of a carbon atom by the plant and its conversion back to CO2 is extremely variable, ranging between a few hours and thousands of years. How long it remains part of organic compounds will depend on its turnover within the plant and, eventually, as part of soil organic matter.Carbon assimilated by plants is translocated to plant organs where it can be used as building material for structural biomass, for storage or as substrate for respiration. Carbon imported into roots can also be exudated or transferred to symbionts such as mycorrhizal fungi (Farrar, 1999). The amount of assimilated carbon used for each purpose will depend on the plant’s requirements, which are further determined by plant and environmental factors. Different studies on a number of plant species have shown the amount of carbon respired to be, on average, 50% of the carbon assimilated through photosynthesis per unit time, with numbers ranging between 35% and 80%(Lambers, 1985; Amthor, 2000a). Other studies have shown that, on average, nearly half of the carbohydrates from photosynthesis are translocated to roots where around 40% of this carbon is used for respiration (Lambers, 1987; Farrar and Williams, 1990). However, these proportions can vary. Amounts of carbon respired by roots