Oxygen Consumption: Photorespiration and Chlororespiration
Oxygen Consumption: Photorespiration and Chlororespiration
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耗氧量：光呼吸和氯呼吸
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
J. Raven
中科院分区：
文献类型：
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作者：
J. Beardall;A. Quigg;J. Raven
本章讨论藻类中与光合作用产氧反应相反的两个过程，即光呼吸和叶绿体呼吸，这两个过程涉及碳水化合物的氧化和/或氧气的消耗。光呼吸与核酮糖 - 1,5 - 二磷酸羧化酶/加氧酶（Rubisco）的加氧酶活性以及细胞弥补否则会从系统中损失的碳和能量的机制有关。藻类细胞进行光呼吸的程度取决于Rubisco对两种竞争底物O₂和CO₂的特异性、细胞是否具有活跃的CO₂浓缩机制（CCM）以及一些环境因素，如温度和光子通量。人们认为，在发生光呼吸的情况下，它与CCM一起在避免通过Rubisco获取碳的低效性以及回收一些可能作为分泌的乙醇酸损失给细胞的碳和能量方面发挥作用。在某些情况下，当同化过程不足以耗散吸收的光能时，在高光和/或低CO₂条件下，光呼吸也可作为一种能量耗散机制。
This chapter discusses two of the processes, namely photorespiration and chlororespiration, in algae that run counter to the oxygen-yielding reactions of photosynthesis and which involve the oxidation of carbohydrate and/or the consumption of oxygen. Photorespiration is associated with the oxygenase activity of Rubisco and the mechanisms by which cells recoup carbon and energy that would otherwise be lost from the system. The degree to which algal cells will carry out photorespiration depends on the specificity of the enzyme Rubisco for the two competing substrates O2 and CO2, whether or not the cells possess an active CO2 concentrating mechanism (CCM), and a number of environmental factors such as temperature and photon flux. Photorespiration, where it occurs, is believed to fulfill, together with a CCM, a role in avoiding the inefficiencies of carbon acquisition via Rubisco and in recovering some of the carbon and energy that could potentially be lost to the cell as excreted glycolate. In some circumstances photorespiration could also act as a mechanism of energy dissipation under conditions of high light and/or low CO2 when assimilatory processes are insufficient to dissipate absorbed light energy.