Changes in the cell wall and cellulose content of developing cotton fibers investigated by FTIR spectroscopy

Fourier transform infrared (FTIR) spectra of cotton fibers harvested at different stages of development were acquired using Universal Attenuated Total Reflectance FTIR (UATR-FTIR). The main goal of the study was to monitor cell wall changes occurring during different phases of cotton fiber development. Two cultivars of Gossypium hirsutum L. were planted in a greenhouse (Texas Marker-1 and TX55). On the day of flowering, individual flowers were tagged and bolls were harvested. From fibers harvested on numerous days between 10 and 56 dpa, the FTIR spectra were acquired using UATR (ZnSe-Diamond crystal) with no special sample preparation. The changes in the FTIR spectra were used to document the timing of the transition between primary and secondary cell wall synthesis. Changes in cellulose during cotton fiber growth and development were identified through changes in numerous vibrations within the spectra. The intensity of the vibration bands at 667 and 897 cm−1 correlated with percentage of cellulose analyzed chemically.