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Opposite carbon isotope discrimination during dark respiration in leaves versus roots – a review
Author(s) -
Ghashghaie Jaleh,
Badeck Franz W.
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12563
Subject(s) - photosynthesis , autotroph , fractionation , respiration , isotopes of carbon , botany , heterotroph , δ13c , biology , chemistry , stable isotope ratio , environmental chemistry , total organic carbon , bacteria , paleontology , physics , organic chemistry , quantum mechanics
Summary In general, leaves are 13 C‐depleted compared with all other organs (e.g. roots, stem/trunk and fruits). Different hypotheses are formulated in the literature to explain this difference. One of these states that CO 2 respired by leaves in the dark is 13 C‐enriched compared with leaf organic matter, while it is 13 C‐depleted in the case of root respiration. The opposite respiratory fractionation between leaves and roots was invoked as an explanation for the widespread between‐organ isotopic differences. After summarizing the basics of photosynthetic and post‐photosynthetic discrimination, we mainly review the recent findings on the isotopic composition of CO 2 respired by leaves (autotrophic organs) and roots (heterotrophic organs) compared with respective plant material (i.e. apparent respiratory fractionation) as well as its metabolic origin. The potential impact of such fractionation on the isotopic signal of organic matter ( OM ) is discussed. Some perspectives for future studies are also proposed .ContentsSummary 751 I. Introduction 751 II. Photosynthetic carbon isotope discrimination 752 III. Post‐photosynthetic discrimination 753 IV. Apparent dark respiratory fractionation in leaves 754 V. Root‐respired CO 2 is generally 13 C‐depleted compared with root OM, except in C 3 woody plants 757 VI. δ 13 C R of leaves and roots diverges at leaf autotrophy onset 762 VII. Metabolic pathways potentially implied in 13 C depletion in root‐respired CO 2 763 VIII. A glance at stem respiration 765 IX. Impact on carbon isotope composition of plant OM 765 X. Conclusions 766Acknowledgements 766References 766