Effects of leaf water evaporative 2H‐enrichment and biosynthetic fractionation on leaf wax n‐alkane δ2H values in C3 and C4 grasses. (9th September 2016)

• Record Type: Journal Article
• Authors: Gamarra, B.; Sachse, D.; Kahmen, A.
• Is Part Of: Plant, cell and environment. Volume 39:Number 11(2016)
• Page Start: 2390
• Page End: 2403
• Publication Date: 2016-09-09
• Subjects: biosynthetic fractionation -- C3 and C4 grasses -- deuterium -- leaf water evaporative 2H‐enrichment -- leaf wax n‐alkanes; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.12789
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Leaf wax n ‐alkane δ 2 H values carry important information about environmental and ecophysiological processes in plants. However, the physiological and biochemical drivers that shape leaf wax n ‐alkane δ 2 H values are not completely understood. It is particularly unclear why n ‐alkanes in grasses are typically 2 H‐depleted compared with plants from other taxonomic groups such as dicotyledonous plants and why C3 grasses are 2 H‐depleted compared with C4 grasses. To resolve these uncertainties, we quantified the effects of leaf water evaporative 2 H‐enrichment and biosynthetic hydrogen isotope fractionation on n ‐alkane δ 2 H values for a range of C3 and C4 grasses grown in climate‐controlled chambers. We found that only a fraction of leaf water evaporative 2 H‐enrichment is imprinted on the leaf wax n ‐alkane δ 2 H values in grasses. This is interesting, as previous studies have shown in dicotyledonous plants a nearly complete transfer of this 2 H‐enrichment to the n ‐alkane δ 2 H values. We thus infer that the typically observed 2 H‐depletion of n ‐alkanes in grasses (as opposed to dicots) is because only a fraction of the leaf water evaporative 2 H‐enrichment is imprinted on the δ 2 H values. Our experiments also show that differences in n ‐alkane δ 2 H values between C3 and C4 grasses are largely the result of systematic differences in biosynthetic fractionation between these two plant groups, which was on average −198‰ and−159‰ for C3 and C4 grasses, respectively. Abstract : We present novel and exciting data on how leaf wax n‐alkane δ2H values from grasses are affected by plant physiological (leaf water evaporative 2H‐enrichment) or biochemical processes (biosynthetic hydrogen isotope fractionation). These results are very interesting because they shed new light on how naturally observed differences between δ2H values from C3 and C4 grasses and dicots can be explained by systematic differences in the biosynthesis of n‐alkanes between these plant group (i.e. largely driven by NADPH origins).