Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species.
Plant Cell Environ
; 40(8): 1658-1670, 2017 Aug.
Article
en En
| MEDLINE
| ID: mdl-28436078
ABSTRACT
Almost no δ18 O data are available for leaf carbohydrates, leaving a gap in the understanding of the δ18 O relationship between leaf water and cellulose. We measured δ18 O values of bulk leaf water (δ18 OLW ) and individual leaf carbohydrates (e.g. fructose, glucose and sucrose) in grass and tree species and δ18 O of leaf cellulose in grasses. The grasses were grown under two relative humidity (rH) conditions. Sucrose was generally 18 O-enriched compared with hexoses across all species with an apparent biosynthetic fractionation factor (εbio ) of more than 27 relative to δ18 OLW , which might be explained by isotopic leaf water and sucrose synthesis gradients. δ18 OLW and δ18 O values of carbohydrates and cellulose in grasses were strongly related, indicating that the leaf water signal in carbohydrates was transferred to cellulose (εbio = 25.1). Interestingly, damping factor pex px , which reflects oxygen isotope exchange with less enriched water during cellulose synthesis, responded to rH conditions if modelled from δ18 OLW but not if modelled directly from δ18 O of individual carbohydrates. We conclude that δ18 OLW is not always a good substitute for δ18 O of synthesis water due to isotopic leaf water gradients. Thus, compound-specific δ18 O analyses of individual carbohydrates are helpful to better constrain (post-)photosynthetic isotope fractionation processes in plants.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Isótopos de Oxígeno
/
Árboles
/
Carbohidratos
/
Hojas de la Planta
/
Poaceae
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Plant Cell Environ
Asunto de la revista:
BOTANICA
Año:
2017
Tipo del documento:
Article
País de afiliación:
Suiza