Exploring feature selection of St John's wort grown under different light spectra using H-NMR spectroscopy.

Introduction: Nuclear magnetic resonance (NMR) spectroscopy combined with multivariate statistical analysis can provide tools to help detect differences in plant chemistry when grown under varying conditions. Hypericum perforatum, or Saint John's wort, plants are a suitable model to explore methods of discrimination between early stage plants grown in different conditions.

Objectives: The purpose of this work was to develop a method for identifying differences in chemical profiles between young Hypericum perforatum plants grown under different lighting conditions.

Material And Methods: Cuttings were grown for 3 weeks under different light conditions. Plant extracts were prepared in MeOD-d and analysed by H-NMR. A multivariate analysis method of the NMR data was developed in an effort to determine variations in chemical profiles.

Results: The method identified specific metabolites as drivers of difference between the plants grown under different light conditions. STOCSY (statistical total correlation spectroscopy) and quantification of highlighted metabolites supported the findings of the multivariate analysis. Glutamine, sucrose and fructose were found to be chemical markers of light quality in this study.

Conclusion: NMR metabolomics using a medium field instrument could find differences in plant chemistry when grown in different conditions. This method could easily be extended to benchtop instruments and be used for crop monitoring and growth condition optimisation.