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Seasonal dynamics in the stable carbon isotope composition ( δ 13 C) from non‐leafy branch, trunk and coarse root CO 2 efflux of adult deciduous ( Fagus sylvatica ) and evergreen ( Picea abies ) trees
Author(s) -
KUPTZ DANIEL,
MATYSSEK RAINER,
GRAMS THORSTEN E. E.
Publication year - 2011
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 - 10.1111/j.1365-3040.2010.02246.x
Subject(s) - beech , fagus sylvatica , evergreen , botany , deciduous , photosynthesis , leafy , picea abies , biology , horticulture , chemistry
Respiration is a substantial driver of carbon (C) flux in forest ecosystems and stable C isotopes provide an excellent tool for its investigation. We studied seasonal dynamics in δ 13 C of CO 2 efflux ( δ 13 C E ) from non‐leafy branches, upper and lower trunks and coarse roots of adult trees, comparing deciduous Fagus sylvatica (European beech) with evergreen Picea abies (Norway spruce). In both species, we observed strong and similar seasonal dynamics in the δ 13 C E of above‐ground plant components, whereas δ 13 C E of coarse roots was rather stable. During summer, δ 13 C E of trunks was about −28.2‰ (Beech) and −26.8‰ (Spruce). During winter dormancy, δ 13 C E increased by 5.6–9.1‰. The observed dynamics are likely related to a switch from growth to starch accumulation during fall and remobilization of starch, low TCA cycle activity and accumulation of malate by PEPc during winter. The seasonal δ 13 C E pattern of branches of Beech and upper trunks of Spruce was less variable, probably because these organs were additionally supplied by winter photosynthesis. In view of our results and pervious studies, we conclude that the pronounced increases in δ 13 C E of trunks during the winter results from interrupted access to recent photosynthates.