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Seasonal variations drive short‐term dynamics and partitioning of recently assimilated carbon in the foliage of adult beech and pine
Author(s) -
Desalme Dorine,
Priault Pierrick,
Gérant Dominique,
Dannoura Masako,
Maillard Pascale,
Plain Caroline,
Epron Daniel
Publication year - 2017
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.14124
Subject(s) - beech , perennial plant , botany , phenology , fagus sylvatica , evergreen , biology , growing season , annual growth cycle of grapevines , dormancy , interspecific competition , deciduous , horticulture , shoot , germination
Summary13 CO 2 pulse‐labelling experiments were performed in situ on adult beeches ( Fagus sylvatica ) and pines ( Pinus pinaster ) at different phenological stages to study seasonal and interspecific short‐term dynamics and partitioning of recently assimilated carbon (C) in leaves. Polar fraction ( PF , including soluble sugars, amino acids and organic acids) and starch were purified from foliage sampled during a 10‐d chase period. C contents, isotopic compositions and 13 C dynamics parameters were determined in bulk foliage, PF and starch. Decrease in 13 C amount in bulk foliage followed a two‐pool exponential model highlighting 13 C partitioning between ‘mobile’ and ‘stable’ pools, the relative proportion of the latter being maximal in beech leaves in May. Early in the growing season, new foliage acted as a strong C sink in both species, but although young leaves and needles were already photosynthesizing, the latter were still supplied with previous‐year needle photosynthates 2 months after budburst. Mean 13 C residence times ( MRT ) were minimal in summer, indicating fast photosynthate export to supply perennial organ growth in both species. In late summer, MRT differed between senescing beech leaves and overwintering pine needles. Seasonal variations of 13 C partitioning and dynamics in field‐grown tree foliage are closely linked to phenological differences between deciduous and evergreen trees.