Hydrogen isotopic compositions of plant leaf lipids are unaffected by a twofold pCO 2 change in growth chambers

Abstract

Hydrogen isotopic compositions of leaf lipids have potential for reconstructing past hydrological changes. However, the effect of pCO 2 levels on leaf lipid D/H values ( δD values) is unknown. Here, we show that leaf lipid ( n-alkanes and n-alkanoic acids) δD values of thirteen plant species grown in chambers are unaffected by a twofold change in ambient pCO 2 level. We hypothesize that the effect of enhanced evapotranspiration at lower CO 2 is accompanied by an increase in kinetic hydrogen isotopic fractionation due to lower rate of plant growth, and vice versa.