Optical Properties of Lentil Seed Coats Using Fiber-Optic Spectroscopy

Abstract

HighlightsA fiber-optic spectroscopy system was set up and validated for measurement of optical properties of lentil seed coat.Light transmission properties of major lentil seed coat types were measured to evaluate their protective ability.Light transmission was detected mainly in the UVA and visible regions in all seed coat types except zero tannin.The protective abilities differed depending on seed coat type (important in breeding for cotyledon protection).Abstract. The light transmission of 20 lentil genotypes, representing six color classes (black, green, tan, brown grey, and zero tannin) was investigated to determine the degree to which seed coats prevent light transmission and possible photodegradation of cotyledon color. A fiber-optic spectroscopy system was set up for measurement; it consisted a deuterium-halogen light source, spectrometer, fiber-optic incidence and transmission probes, and sample holders. The nadir-aligned transmission spectra were measured in wavelength ranges of 250 to 850 nm. To study variability in light transmission of the different seed coat types, the curves were integrated in three wavelength regions to obtain Cumulative UV Transmission (CUVT, 250 to 400 nm), Cumulative VIS Transmission (CVIST, 401 to 700 nm), and Cumulative NIR Transmission (CNIRT, 701 to 850 nm), respectively. Tests for significant differences in light transmission were then done using analysis of variance (ANOVA) via General Linear Modelling and Posthoc GLM Tukey tests. Results showed that all the seed coat types, except zero tannin, showed no detectable transmission of UV light from 250 to 315 nm. Black seed coats showed detectable transmission from 615 to 850 nm, while other seed coat types transmitted varying percentages of light from 315 to 850 nm. The results of ANOVA showed that there were significant (p<0.05) differences in light transmission properties of the major seed coat types. Keywords: Fiber optics, Lentils, Light transmission, Pulse quality, Spectroscopy, Seed coat.