Detection of Fusarium infected seeds of cereal plants by the fluorescence method.

Abstract

Infection of seeds of cereal plants with fusarium affects their optical luminescent properties. The spectral characteristics of excitation (absorption) in the range of 180-700 nm of healthy and infected seeds of wheat, barley and oats were measured. The greatest difference in the excitation spectra of healthy and infected seeds was observed in the short-wave range of 220-450 nm. At the same time, the excitation characteristics of infected seeds were higher than those of healthy ones, and the integral parameter Η in the entire range was 10-56% higher. A new maximum appeared at the wavelength of 232 nm and the maximum value increased by 362 nm. The spectral characteristics were measured when excited by radiation at wavelengths of 232, 362, 424, 485, 528 nm and the luminescence fluxes were calculated. It is established that the photoluminescence fluxes Φ in the short-wave ranges of 290-380 nm increase by 1.58-3.14 times and 390-550 nm-by 1.44-2.54 times. The fluxes in longer wavelength ranges do not change systematically and less significantly: for wheat, they decrease by 12% and increase by 19%, for barley, they decrease by 10% and increase by 33%. The flux decreases by 43-71% for oats. Based on the results obtained for cereal seeds, it is possible to further develop a method for detecting fusarium infection with absolute measurements of photoluminescence fluxes in the range of 290-380 nm, or when measuring photoluminescence ratios: for wheat seeds when excited with wavelengths of 424 nm and 232 nm (Φ424/Φ232); for barley seeds-when excited with wavelengths of 485 nm and 232 nm (Φ485/Φ232) and for oat seeds-when excited with wavelengths of 424 nm and 362 nm (Φ424/Φ362).