Hydrogen isotope response to changing salinity and rainfall in Australian mangroves.
Plant Cell Environ
; 38(12): 2674-87, 2015 Dec.
Article
en En
| MEDLINE
| ID: mdl-26013204
ABSTRACT
Hydrogen isotope ratios ((2) H/(1) H, δ(2) H) of leaf waxes covary with those in precipitation and are therefore a useful paleohydrologic proxy. Mangroves are an exception to this relationship because their δ(2) H values are also influenced by salinity. The mechanisms underlying this response were investigated by measuring leaf lipid δ(2) H and leaf and xylem water δ(2) H and δ(18) O values from three mangrove species over 9.5 months in a subtropical Australian estuary. Net (2) H/(1) H fractionation between surface water and leaf lipids decreased by 0.5-1.0 ppt(-1) for n-alkanes and 0.4-0.8 ppt(-1) for isoprenoids. Xylem water was (2) H depleted relative to surface water, reflecting (2) H discrimination of 4-10 during water uptake at all salinities and opportunistic uptake of freshwater at high salinity. However, leaf water (2) H enrichment relative to estuary water was insensitive to salinity and identical for all species. Therefore, variations in leaf and xylem water δ(2) H values cannot explain the salinity-dependent (2) H depletion in leaf lipids, nor the 30 range in leaf lipid δ(2) H values among species. Biochemical changes in direct response to salt stress, such as increased compatible solute production or preferential use of stored carbohydrates, and/or the timing of lipid production and subsequent turnover rates, are more likely causes.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Agua
/
Avicennia
/
Rhizophoraceae
/
Hidrógeno
Idioma:
En
Revista:
Plant Cell Environ
Asunto de la revista:
BOTANICA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Estados Unidos