Study On The Identification Of Rapeseed Seed Aging And The Effect Of Salinity On Seed Germination By FTIR Spectroscopic

Rapeseed is a high-quality oil-crop with valuable characteristics such as rapid growth,high yield,high nutritional value,strong resistance,salt alkali resistance,reduced soil wind erosion and soil erosion.It is a high-quality oil crop.Seed aging and soil salinization can affect seed germination,reduce its stress resistance,and have a serious impact on yield.Therefore,the analysis and identification of seed aging and the study of seed germination under salt and alkali stress are of great significance for agricultural production.In this paper,Fourier transform infrared spectroscopy（FTIR）and two-dimensional correlation infrared spectroscopy（2D-IR）combined with curve fitting and principal component analysis（PCA）were used to identify seed aging and to study the effects of salt and alkali（Na Cl,Na₂CO₃）stress on the germination of rapeseed seeds.The research work is as follows:1.Using FTIR,SD-IR,and 2D-IR combined with PCA and curve fitting,the infrared spectrum analysis and identification of rapeseed seed aging degree were conducted.The results showed that the original infrared spectra of rapeseed seeds were generally similar,mainly composed of lipid peaks,carbohydrate peaks,and protein peaks.The second derivative infrared spectroscopy（SD-IR）in the range of3000 to 1000 cm^-1showed significant changes in peak intensity.The intensity of the strongest automatic peak and the position of the weak automatic peak in the two-dimensional correlation infrared spectroscopy（2D-IR）vary significantly in the range of 1800 to 1100 cm^-1.Select a range of 2990 to 2830 cm^-1for curve fitting analysis,and the characteristic peak area percentage has significantly changed.Principal component analysis（PCA）can correctly classify five different aging time rape seeds.Research has shown that infrared spectroscopy combined with statistical analysis methods can analyze the mobilization of nutrients in aged seeds and achieve identification of rape seed aging.2.The effects of different concentrations of Na Cl and Na₂CO₃stress on the germination of rape seeds A35 and Huayuza 62 were studied.The germination potential,germination percentage,and germination index of the two rape seeds under Na Cl and Na₂CO₃stress gradually decreased with the increase of stress concentration.The decrease of the two rape seeds under Na₂CO₃stress is more significant than that under Na Cl stress,and the decrease of A35 rape seeds under Na₂CO₃stress is more significant,indicating that the tolerance of the two rape seeds to Na Cl stress is better than that of Na₂CO₃stress,and the resistance of Huayouza 62 rape seeds to Na₂CO₃stress is slightly better than that of A35 rape seeds.The overall characteristic peaks of FTIR spectra of A35 and Huayouza 62 rape seeds after the same days of germination under different concentrations of Na Cl and Na₂CO₃stress were basically similar,and the intensity of the characteristic peaks changed,mainly composed of lipids,sugars,and protein nutrients.In the range of SD-IR from 3000 to 1000 cm^-1,there was a shift in the position of absorption peaks and a change in the intensity of absorption peaks in rape seeds under different concentrations of Na Cl stress;The positions of absorption peaks in rape seeds were similar under different concentrations of Na₂CO₃stress,and the peak intensity of absorption peaks changed.The curve fitting analysis of the original infrared spectra in the range of 2990 to 2830 cm^-1（lipid region）and 1200 to 950 cm^-1（polysaccharide region）of the rapeseed seed spectrum after 8 days of germination showed that the relative content of lipids in rapeseed seeds showed a trend of first decreasing and then increasing under Na Cl stress,while the relative content of sugars showed a dynamic decreasing trend.Under Na₂CO₃stress,the relative content of lipids in rapeseed seeds showed a dynamic increase trend with the increase of Na₂CO₃stress solution concentration.The number of subpeaks under different solution concentrations in A35and Huayuza 62 rapeseed seeds changed in the region of 1200 to 950 cm^-1,and the relative content of carbohydrates showed a dynamic decrease trend.Studies have shown that Fourier transform infrared spectroscopy combined with statistical analysis can identify rape seed aging,and is an effective method for studying the effects of salt and alkali stress on rape seed germination.