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

The hydrogen isotopic composition (δ2H) of plant compounds is increasingly used as a hydro-climatic proxy, however, the interpretation of δ2H values is hampered by potential co-effecting biochemical and biophysical processes. Here, we studied δ2H 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 2H-enrichment in sugars and starch with a decreasing performance induced by increasing NO3-/NH4+ ratios and starch deficiency, and from leaves to roots. However, δ2H values of cellulose and n-alkanes were less affected. We show that relative concentrations of sugars and starch, interlinked with leaf gas-exchange, shape δ2H values of carbohydrates. We thus provide novel insights into drivers of hydrogen isotopic co..., , , # Biochemical and biophysical drivers of the hydrogen isotopic composition of carbohydrates and acetogenic lipids

The dataset holds all the data of this study, including published and unpublished data of a previous study (Ghiasi *et al*. 2021, ref #48, ). The data covers stable isotope data of water, carbohydrates, and n-alkanes, as well as biochemical and biophysical trait data from two tobacco experiments: (a) soil fertilization with varying nitrogen species ratios (NO3-/NH4+) and (b) knockout-induced starch deficiency.

## Description of the data and file structure

The data file contains three sheets: \"Metadata\" describes each of the measured variables of both experiments (e.g., abbreviation, tissue, unit) and gives the data source (e.g., unpublished or published); \"N fertilization\" covers the data of experiment (a); \"Starch deficiency\" covers the data of experiment (b).