Characterization and discrimination of tundra plant leaves by Attenuated Total Reflection Fourier transform infrared spectroscopy

Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is a powerful tool for investigating the biochemical fingerprint of plants, but its applicability to tundra plant leaves has yet to be addressed. The present study aimed to apply ATR-FTIR measurement to characterize tundra plant leaves and to discriminate these among plant species with different growth forms. The ATR-FTIR spectra in the fingerprint region (1800–800 cm⁻¹) of live and dead leaves from 14 tundra plant species of shrubs, forbs, graminoids, and mosses showed a variability in overall appearance among plant species and a degree of similarity between live and dead leaves of the same plant species. Four highest peaks were found at 1637–1575 cm⁻¹, 1452–1406 cm⁻¹, 1325–1313 cm⁻¹, and 1058–1022 cm⁻¹ in these spectra and are attributed to chemical features of lignin, cellulose, and/or oxalate. Principal component analyses showed that leaves of Oxyria digyna and other forbs had distinctive spectral characteristics attributable to the content of oxalate and other putative compounds and that contents of lignin relative to cellulose were generally greater in shrubs than in graminoids and mosses. These results demonstrated that ATR-FTIR spectroscopy is useful for future applications in polar biology and ecology, for example the description of functional traits of arctic plants and decomposition processes by microbes.