In:
Physiologia Plantarum, Wiley, Vol. 123, No. 3 ( 2005-03), p. 288-301
Abstract:
The classical theory of the relationship between gas fluxes and photosynthetic electron fluxes was extended by two additional terms: J L describing flux to electron sinks other than the Calvin cycle, and R L accounting for light‐induced changes in non‐photorespiratory CO 2 evolution. R L comprises two main components, R r resulting from light‐induced decrease in tricarboxylic acid activity, and R S related to extra CO 2 evolution resulting from citrate‐to‐2‐oxoglutarate conversion for N‐assimilation in NO 3 – grown leaves. This extended theory was applied to two experiments. First, A–C i curves (dependence of CO 2 flux on stomatal CO 2 concentration) revealed a higher apparent CO 2 compensation point (Γ* app ) in NO 3 – ‐grown plants than in NH 4 + ‐grown plants. Secondly, photosynthetic electron fluxes at different light intensities were determined by means of the Genty parameter of chlorophyll fluorescence and compared with those calculated from measured CO 2 uptake. Curve‐fitting based on the extended theory provided a coincidence of these two measurements and resulted in higher R S in NO 3 – ‐grown than in NH 4 + ‐grown plants. This difference in R S (about 15% of the CO 2 flux bound by carboxylation) is the same as that obtained from the analysis of Γ* app . Further, the analysis suggests that J L related to the extra electron flux used for N‐assimilation in NO 3 – ‐grown plants is diverted to other sinks in NH 4 + ‐grown plants. SHAM decreased photosynthetic electron flow and O 2 evolution in NH 4 + ‐grown plants, antimycin A in NO 3 – ‐grown plants. The effect of oligomycin was small. The results are discussed in terms of different mechanisms of chloroplast/mitochondrion interaction in NO 3 – ‐ and NH 4 + ‐grown plants, their effects on non‐photorespiratory CO 2 evolution and on Γ* app .
Type of Medium:
Online Resource
ISSN:
0031-9317
,
1399-3054
DOI:
10.1111/ppl.2005.123.issue-3
DOI:
10.1111/j.1399-3054.2005.00467.x
Language:
English
Publisher:
Wiley
Publication Date:
2005
detail.hit.zdb_id:
208872-1
detail.hit.zdb_id:
2020837-6
SSG:
12
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