The metabolic sensitivity of hydrogen isotope fractionation differs between plant compounds

Baan, Jochem; Holloway‐Phillips, Meisha; Nelson, Daniel B.; Kahmen, Ansgar

doi:10.1016/j.phytochem.2022.113563

Cited by 9 publications

(13 citation statements)

References 85 publications

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“…These pathways are expected to produce 2 H-enriched NADPH compared to the photosynthetical pathway (5,41,42). Given that acetogenic lipids are mostly produced in the chloroplast under illumination and that about 50% of their carbon-bound H atoms are derived from NADPH, this results in typically 2 H-depleted acetogenic lipids (7,9). Structural carbohydrates, like cellulose, are primarily synthesized in the cytosol.…”

Section: Biochemical Considerationsmentioning

confidence: 99%

“…Hydrogen isotope ratios (δ 2 H) measured on acetogenic lipids (e.g., n-alkanes) and carbohydrates (e.g., cellulose) extracted from plant tissues of aquatic or terrestrial archives are widely applied for studying past hydroclimatic conditions (1)(2)(3)(4). A growing body of evidence suggests that δ 2 H values of carbohydrates and lipids may integrate not only (eco-)climatic but also biophysical and biochemical information (5)(6)(7)(8)(9). Such nonclimatic information may hinder the reconstruction of climatic conditions based on δ 2 H values and urges for a better understanding of the key drivers of δ 2 H values in plant compounds.…”

Section: Introductionmentioning

confidence: 99%

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Biochemical and biophysical drivers of the hydrogen isotopic composition of carbohydrates and acetogenic lipids

Lehmann,

Schuler,

Werner

et al. 2024

Sci. Adv.

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The hydrogen isotopic composition (δ 2 H) of plant compounds is increasingly used as a hydroclimatic proxy; however, the interpretation of δ 2 H values is hampered by potential coeffecting biochemical and biophysical processes. Here, we studied δ 2 H values of water and carbohydrates in leaves and roots, and of leaf n -alkanes, in two distinct tobacco ( Nicotiana sylvestris ) experiments. Large differences in plant performance and biochemistry resulted from (a) soil fertilization with varying nitrogen (N) species ratios and (b) knockout-induced starch deficiency. We observed a strong 2 H-enrichment in sugars and starch with a decreasing performance induced by increasing NO 3 − /NH 4 + ratios and starch deficiency, as well as from leaves to roots. However, δ 2 H values of cellulose and n -alkanes were less affected. We show that relative concentrations of sugars and starch, interlinked with leaf gas exchange, shape δ 2 H values of carbohydrates. We thus provide insights into drivers of hydrogen isotopic composition of plant compounds and into the mechanistic modeling of plant cellulose δ 2 H values.

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Section: Biochemical Considerationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Biochemical and biophysical drivers of the hydrogen isotopic composition of carbohydrates and acetogenic lipids

Lehmann,

Schuler,

Werner

et al. 2024

Sci. Adv.

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“…2022 ), which led to un increased number of δ 2 H studies ( Wieland et al. 2022 ; Baan et al. 2023 ; Schuler et al.…”

Section: Introductionmentioning

confidence: 99%

Different responses of oxygen and hydrogen isotopes in leaf and tree-ring organic matter to lethal soil drought

Lehmann,

Diao,

Ouyang

et al. 2024

Tree Physiology

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Summary The oxygen and hydrogen isotopic composition (δ18O, δ2H) of plant tissues are key tools for the reconstruction of hydrological and plant physiological processes and may therefore be used for disentangling reasons of tree mortality. However, how both elements respond to soil drought conditions before death have rarely been investigated. To test this, we performed a greenhouse study and determined predisposing fertilization and lethal soil drought effects on δ18O and δ2H values of organic matter (OM) in leaves and tree rings of living and dead saplings of five European tree species. For mechanistic insights, we additionally measured isotopic (i.e., δ18O and δ2H values of leaf and twig water), physiological (i.e., leaf water potential and gas-exchange) and metabolic traits (i.e., leaf and stem non-structural carbohydrate concentration, C:N ratios). Across all species, lethal soil drought generally caused a homogenous 2H-enrichment in leaf and tree-ring OM, but a low and heterogenous δ18O response in the same tissues. Unlike δ18O values, δ2H values of tree-ring OM were correlated with those of leaf and twig water and with plant physiological traits across treatments and species. The 2H-enrichment in plant OM also went along with a decrease in stem starch concentrations under soil drought compared to well-watered conditions. In contrast, the predisposing fertilization had generally no significant effect on any tested isotopic, physiological, and metabolic traits. We propose that the 2H-enrichment in the dead trees is related to (i) the plant water isotopic composition, (ii) metabolic processes shaping leaf non-structural carbohydrates, (iii) the use of carbon reserves for growth, and (iv) species-specific physiological adjustments. The homogenous stress imprint on δ2H but not on δ18O suggests that the former could be used as a proxy to reconstruct soil droughts and underlying processes of tree mortality.

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“…Also, position‐specific intramolecular δ 2 H analysis has suggested different fractionation factors for individual H‐atom positions, which respond to environmental conditions (Schleucher et al ., 1999; Augusti et al ., 2006; Wieloch et al ., 2022a,b). Variation in the isotopic offset between cellulose δ 2 H and plant water pools also supports the view that fractionation factors can change with species and growth conditions (Sternberg & Deniro, 1983; Cormier et al ., 2018, 2019; Baan et al ., 2022, 2023; Lehmann et al ., 2022).…”

Section: Introductionmentioning

confidence: 99%

Covariation between oxygen and hydrogen stable isotopes declines along the path from xylem water to wood cellulose across an aridity gradient

Holloway‐Phillips,

Cernusak,

Nelson

et al. 2023

New Phytologist

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Summary Oxygen and hydrogen isotopes of cellulose in plant biology are commonly used to infer environmental conditions, often from time series measurements of tree rings. However, the covariation (or the lack thereof) between δ18O and δ2H in plant cellulose is still poorly understood. We compared plant water, and leaf and branch cellulose from dominant tree species across an aridity gradient in Northern Australia, to examine how δ18O and δ2H relate to each other and to mean annual precipitation (MAP). We identified a decline in covariation from xylem to leaf water, and onwards from leaf to branch wood cellulose. Covariation in leaf water isotopic enrichment (Δ) was partially preserved in leaf cellulose but not branch wood cellulose. Furthermore, whilst δ2H was well‐correlated between leaf and branch, there was an offset in δ18O between organs that increased with decreasing MAP. Our findings strongly suggest that postphotosynthetic isotope exchange with water is more apparent for oxygen isotopes, whereas variable kinetic and nonequilibrium isotope effects add complexity to interpreting metabolic‐induced δ2H patterns. Varying oxygen isotope exchange in wood and leaf cellulose must be accounted for when δ18O is used to reconstruct climatic scenarios. Conversely, comparing δ2H and δ18O patterns may reveal environmentally induced shifts in metabolism.

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The metabolic sensitivity of hydrogen isotope fractionation differs between plant compounds

Cited by 9 publications

References 85 publications

Biochemical and biophysical drivers of the hydrogen isotopic composition of carbohydrates and acetogenic lipids

Biochemical and biophysical drivers of the hydrogen isotopic composition of carbohydrates and acetogenic lipids

Different responses of oxygen and hydrogen isotopes in leaf and tree-ring organic matter to lethal soil drought

Covariation between oxygen and hydrogen stable isotopes declines along the path from xylem water to wood cellulose across an aridity gradient

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