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Compound‐specific differences in 13 C of soluble carbohydrates in leaves and phloem of 6‐month‐old Eucalyptus globulus (Labill)
Author(s) -
MERCHANT ANDREW,
WILD BIRGIT,
RICHTER ANDREAS,
BELLOT SIDONIE,
ADAMS MARK A.,
DREYER ERWIN
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.1365-3040.2011.02359.x
Subject(s) - phloem , raffinose , sucrose , eucalyptus globulus , botany , sugar , chemistry , eucalyptus , carbon fibers , biology , horticulture , biochemistry , materials science , composite number , composite material
Movement of photoassimilates from leaves to phloem is an important step for the flux of carbon through plants. Fractionation of carbon isotopes during this process may influence their abundance in heterotrophic tissues. We subjected Eucalyptus globulus to 20, 25 and 28 °C ambient growth temperatures and measured compound‐specific δ 13 C of carbohydrates obtained from leaves and bled phloem sap. We compared δ 13 C of sucrose and raffinose obtained from leaf or phloem and of total leaf soluble carbon, with modelled values predicted by leaf gas exchange. Changes in δ 13 C of sucrose and raffinose obtained from either leaves or phloem sap were more tightly coupled to changes in c i / c a than was δ 13 C of leaf soluble carbon. At 25 and 28 °C, sucrose and raffinose were enriched in 13 C compared to leaf soluble carbon and predicted values – irrespective of tissue type. Phloem sucrose was depleted and raffinose enriched in 13 C compared to leaf extracts. Intermolecular and tissue‐specific δ 13 C reveal that multiple systematic factors influence 13 C composition during export to phloem. Predicting sensitivity of these factors to changes in plant physiological status will improve our ability to infer plant function at a range of temporal and spatial scales.