Atmospheric CO2 concentration does not directly affect leaf respiration in bean or poplar
Atmospheric CO2 concentration does not directly affect leaf respiration in bean or poplar
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DOI：
10.1046/j.0016-8025.2001.00776.x
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发表时间：
2001-11-01
影响因子：
7.3
通讯作者：
Jahnke, S
中科院分区：
文献类型：
--
作者：
Jahnke, S
大气中二氧化碳浓度升高是否对植物在黑暗中的呼吸有直接（短期）影响，这是一个有争议的问题。当C-a加倍时，一些作者发现暗呼吸没有（或只有轻微）变化，而大多数研究表明呼吸抑制15-20%。目前的研究表明，测量伪影——特别是叶室垫片和叶表面之间的泄漏、二氧化碳记忆和气体交换系统的泄漏效应，以及蒸腾作用引起的水蒸气（“水稀释”）对Delta CO2测量的影响——可能导致比一般讨论的更大的误差。一个以三种不同方式使用的气体交换系统：作为一个封闭系统，由于封闭叶片的呼吸作用，C-a从200 μ mol(CO2) mol(-1)（空气）不断增加；描述了C-a在350或2000 μ mol mol（-1）期间反复关闭和打开的间歇性封闭系统，以及C-a在350和2000 μ mol mol（-1）之间变化的开放系统。在对照实验（空叶室）中，仔细评估了各自的系统特性。当考虑到所有相关系统参数时，即使C-a增加到4200 mu mol mol(-1)，也没有发现CO2短期变化对豆类和杨树叶片暗CO2外排的影响。结果表明，大气CO2浓度升高不会直接抑制大豆和杨树的叶片呼吸。
It is a matter of debate if there is a direct (short-term) effect of elevated atmospheric CO2 concentration (C-a) on plant respiration in the dark. When C-a doubles, some authors found no (or only minor) changes in dark respiration, whereas most studies suggest a respiratory inhibition of 15-20%. The present study shows that the measurement artefacts-particularly leaks between leaf chamber gaskets and leaf surface, CO2 memory and leakage effects of gas exchange systems as well as the water vapour ('water dilution') effect on Delta CO2 measurement caused by transpiration-may result in larger errors than generally discussed. A gas exchange system that was used in three different ways-as a closed system in which C-a increased continuously from 200 to 4200 mu mol (CO2) mol(-1) (air) due to respiration of the enclosed leaf; as an intermittently closed system that was repeatedly closed and opened during C-a periods of either 350 or 2000 mu mol mol(-1), and as an open system in which C-a varied between 350 and 2000 mu mol mol(-1)- is described. In control experiments (with an empty leaf chamber), the respective system characteristics were evaluated carefully. When all relevant system parameters were taken into account, no effects of short-term changes in CO2 on dark CO2 efflux of bean and poplar leaves were found, even when C-a increased to 4200 mu mol mol(-1). It is concluded that the leaf respiration of bean and poplar is not directly inhibited by elevated atmospheric CO2.