Quantitative Assessment of Cold Injury in Tea Plants by Terahertz Spectroscopy Method

Cold injury (CI) causes irreversible damage to tea plants, which results in decline the quality of famous teas and huge economic loss. A new, quick, non-destructive method is provided assess CI leaf based on terahertz (THz) spectroscopy. Absorbance samples was measured with THz spectroscopy frequency bands from 0.1 1.6 under low temperature treatments 4.0, 0, −2.5, −5.0, −7.5, −10.0 °C. Fast Fourier transformation explored decompose endpoint signal improve ratio air convert time-domain spectra corresponding frequency-domain spectra. To separation overlap signals caused by substantial scattering injured cells leaf, two-dimensional correlation (2DCOS) average intensity (AI) were introduced into partial least squares regression (PLSR) build 2DCOS–PLSR AI–PLSR models. Quantitative assessments models conducted evaluate three The assessment showed that coefficients model (R2D) 0.7873, 0.8305, 0.9103, respectively. root mean square errors (RMSE2D) 0.6032, 0.5763, 0.5221, For model, RAI values 0.7477, 0.7691, 0.8974, RMSEAI 0.6038, 0.5962, 0.5797. combination a better benchmark for input interval selection improved accuracy cold-injury detection results.