Know your enemy: Application of ATR-FTIR spectroscopy to invasive species control

Abstract

Extreme weather and globalisation leave our climate vulnerable to invasion by alien species, which have negative impacts on the economy, biodiversity, and ecosystem services. Rapid and accurate identification is key to the control of invasive alien species. However, visually similar species hinder conservation efforts, for example hybrids within the Japanese Knotweed complex. We applied the novel method of ATR-FTIR spectroscopy combined with chemometrics (mathematics applied to chemical data) to historic herbarium samples, taking 1580 spectra in total. Samples included five species from within the interbreeding Japanese Knotweed complex (including three varieties of Japanese Knotweed), six hybrids and five species from the wider Polygonaceae family. Spectral data from herbarium specimens were analysed with several chemometric techniques: support vector machines (SVM) for differentiation between plant types, supported by ploidy levels; principal component analysis loadings and spectral biomarkers to explore differences between the highly invasive Reynoutria japonica var. japonica and its non-invasive counterpart Reynoutria japonica var. compacta; hierarchical cluster analysis (HCA) to investigate the relationship between plants within the Polygonaceae family, of the Fallopia, Reynoutria, Rumex and Fagopyrum genera. ATR-FTIR spectroscopy coupled with SVM successfully differentiated between plant type, leaf surface and geographical location, even in herbarium samples of varying age. Differences between Reynoutria japonica var. japonica and Reynoutria japonica var. compacta included the presence of two polysaccharides, glucomannan and xyloglucan, at higher concentrations in Reynoutria japonica var. japonica than Reynoutria japonica var. compacta. HCA analysis indicated that potential genetic linkages are sometimes masked by environmental factors; an effect that can either be reduced or encouraged by altering the input parameters. Entering the absorbance values for key wavenumbers, previously highlighted by principal component analysis loadings, favours linkages in the resultant HCA dendrogram corresponding to expected genetic relationships, whilst environmental associations are encouraged using the spectral fingerprint region. The ability to distinguish between closely related interbreeding species and hybrids, based on their spectral signature, raises the possibility of using this approach for determining the origin of Japanese knotweed infestations in legal cases where the clonal nature of plants currently makes this difficult and for the targeted control of species and hybrids. These techniques also provide a new method for supporting biogeographical studies.

Influence of sample preparation methods on FTIR spectra for taxonomic identification of tropical trees in the Atlantic forest

“…Among spectroscopic techniques, Fourier Transform Infrared Vibrational Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) stands out as an effective tool for the analysis of plant organic material, aiming at sample classification [ [10] , [11] , [12] ]. FTIR is a non-invasive collection technique that does not generate laboratory waste, is fast and low-cost, allowing the characterization and quantification of organic functional groups that reflect the biochemical composition of plants [ [8] , [9] , [10] ].…”

“…Due to the high versatility of the technique, FTIR-based studies have been applied in various plant research. For example, taxonomic identification of species using leaf samples [ 7 , 10 , 13 ]), pollen [ 12 , 14 , 15 ], and roots [ 16 ], classification of invasive species hybrids [ 17 ], study of the influence of different land uses on grasses [ 18 ], evaluation of plant-environment-atmosphere interaction [ 14 , 19 , 20 ] influence of environmental pollution on pollen composition [ 21 ], change in plant biochemical composition after disease infection [ 22 , 23 ], influence of toxic soils on plants [ 24 ] evaluation of hydrogels use as plant substrate [ 25 ], and evaluation of species with pharmaceutical potential through in situ collection of spectra [ 8 ], among others.…”

S-Adenosyl-L-Methionine and Cu(II) Impact Green Plant Regeneration Efficiency

“…Typical plant tissue spectra exhibit several bands caused by the superimposition of a variety of chemical components. Numerous statistical and/or chemometric techniques have been used to extract more detailed information from the spectra, including supervised and unsupervised techniques [ 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. Regression analysis and calibration standards are combined in this technique to enable the measurement of specific elements in the material under study [ 60 , 61 , 62 ].…”

Nitrification inhibition by polyphenols from invasive Fallopia japonica under copper stress

“…Several plant species are able to inhibit nitrification, a process called biological nitrification inhibition (Subbarao et al., 2007), generating a larger pool of ammonium rather than nitrate. Biological nitrification inhibition is discussed as one of the invasion strategies used by the Fallopia species complex (Cantarel et al., 2020; Dassonville et al., 2011) from the knotweed family (Polygonaceae), which are among the world's most successful invasive plant species (Holden et al., 2022; Lowe et al., 2000). In our context, Fallopia spp.…”