Premium
Atmospheric CO 2 concentration does not directly affect leaf respiration in bean or poplar
Author(s) -
Jahnke S.
Publication year - 2001
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.0016-8025.2001.00776.x
Subject(s) - respiration , transpiration , dilution , chemistry , photosynthesis , horticulture , respiration rate , botany , biology , physics , thermodynamics , biochemistry
It is a matter of debate if there is a direct (short‐term) effect of elevated atmospheric CO 2 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, CO 2 memory and leakage effects of gas exchange systems as well as the water vapour (‘water dilution’) effect on D CO 2 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 m mol (CO 2 ) 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 m mol mol ‐1 , and as an open system in which C a varied between 350 and 2000 m 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 CO 2 on dark CO 2 efflux of bean and poplar leaves were found, even when C a increased to 4200 m mol mol ‐1 . It is concluded that the leaf respiration of bean and poplar is not directly inhibited by elevated atmospheric CO 2 .