Respiratory oxygen uptake is not decreased by an instantaneous elevation of [CO2], but is increased with long-term growth in the field at elevated [Co2]1
Respiratory oxygen uptake is not decreased by an instantaneous elevation of [CO2], but is increased with long-term growth in the field at elevated [Co2]1
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DOI：
10.1104/pp.103.030569
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发表时间：
2004-01-01
期刊：
影响因子：
7.4
通讯作者：
Long, SP
中科院分区：
文献类型：
--
作者：
Davey, PA;Hunt, S;Long, SP
根据之前许多研究的平均值，经常有报道称，二氧化碳浓度（[CO2]）翻倍会导致叶片暗呼吸（以CO2外排测量）的瞬时减少。没有已知的机制来解释这种效应，最近的四项研究表明，呼吸CO2流出的测量容易出现实验伪影，这可能是报告的反应。在此，通过在开放式气体交换系统内使用高分辨率双通道氧气分析仪来测量正常空气中的呼吸O-2摄取，避免了这些伪影。叶O-2吸收测定响应瞬时海拔[CO2]在9个对比物种和长期海拔7个物种从4个田间试验。超过600个单独的呼吸测量未能揭示呼吸O-2吸收的任何减少与[CO2]的瞬时增加。发现呼吸不仅对[CO2]倍增不敏感，而且对5倍增加和降低至零也不敏感。使用广泛的物种和条件，我们证实了早期的报告，抑制呼吸的瞬时海拔[CO2]可能是一个实验的神器。而不是预期的呼吸每单位叶面积在响应长期增长领域在升高[CO2]，有一个显着增加11%和7%的面积和质量的基础上，分别在所有实验中平均。研究结果表明，随着大气[CO2]浓度的升高，叶片暗呼吸作用不减反增。
Averaged across many previous investigations, doubling the CO2 concentration ([CO2]) has frequently been reported to cause an instantaneous reduction of leaf dark respiration measured as CO2 efflux. No known mechanism accounts for this effect, and four recent studies have shown that the measurement of respiratory CO2 efflux is prone to experimental artifacts that could account for the reported response. Here, these artifacts are avoided by use of a high-resolution dual channel oxygen analyzer within an open gas exchange system to measure respiratory O-2 uptake in normal air. Leaf O-2 uptake was determined in response to instantaneous elevation of [CO2] in nine contrasting species and to long-term elevation in seven species from four field experiments. Over six hundred separate measurements of respiration failed to reveal any decrease in respiratory O-2 uptake with an instantaneous increase in [CO2]. Respiration was found insensitive not only to doubling [CO2], but also to a 5-fold increase and to decrease to zero. Using a wide range of species and conditions, we confirm earlier reports that inhibition of respiration by instantaneous elevation of [CO2] is likely an experimental artifact. Instead of the expected decrease in respiration per unit leaf area in response to long-term growth in the field at elevated [CO2], there was a significant increase of 11% and 7% on an area and mass basis, respectively, averaged across all experiments. The findings suggest that leaf dark respiration will increase not decrease as atmospheric [CO2] rises.