Compositional features of cotton plant biomass fractions characterized by attenuated total reflection Fourier transform infrared spectroscopy

• Whole cotton plant biomass was separated into six (mid-season) or nine (pre-harvest) components.
• ATR-FTIR spectra were collected and analyzed for cotton fibers, stems, roots, leaves, seeds, branches, petioles, burs, and bracts.
• The nine biomass components clustered to two groups per principal component analysis.
• ATR-FTIR could be a rapid and non-destructive technique to assess cotton plant growth and biomass production.

Cotton is one of the most important and widely grown crops in the world. In addition to natural textile fiber production as a primary purpose, it yields a high grade vegetable oil for human consumption and also carbohydrate fiber and protein byproducts for animal feed. In this work, attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy was applied to characterize the cotton plant biomass fractions. Furthermore, principal component analysis (PCA) of these ATR-FTIR spectra were performed to evaluate the similarity or dissimilarity of these biomass fractions from different parts of cotton plants, and the same plant parts collected between mid-season and pre-defoliation stages. These data revealed the more rapid accumulation of major carbohydrate components in main stems, roots, and branches than in petioles and leaf blades, increased our understanding of the cotton growth mechanism. PCA revealed that the ATR-FTIR spectra of cotton biomass fractions fell into two distinct clusters representing two types of cotton plant parts: Stem cluster (main stems, roots, branches, and petioles) and Leaf cluster (leaf blades, bracts, bur, and/or reproductive parts). Such clustering information could be helpful in selecting the FT-IR measurement parameters for assessing cotton plant growth, nutrition management, and biomass production.