Study Of Influencing Factors On THz-TDS Test And Interspecific Relationship Of Alfalfa Forages Seeds

Forage alfalfa resources are an extremely important resource in human society and play an important role in the harmonious development of natural ecology.However,the current research on the protection of pasture germplasm resources and related technologies is not perfect,especially the application of terahertz technology in this respect.This topic mainly carries out related research on this problem,and explores the problems existing in the process of identifying forage species and exploring the differences between species in the terahertz time-domain spectroscopy.In this paper,the alfalfa forage seeds are the research objects.They were tested in a transmissive terahertz time-domain spectroscopy system to analyze the influencing factors.Specifically,quantitative experiment determined that the drying time for forage seeds was 8 hours.The results in the effective terahertz 0-2 THz band show that the grain size of the forage seed samples has a significant effect on the test results: the smaller the particle size,the smaller the refractive index of the sample.As the thickness of the sample increases,the intensity of the transmission spectrum also decays in turn.Not only that,the different mass ratios of polyethylene in the sample will not affect the absorption coefficient of the sample,but the effect on the refractive index will maintain a certain regularity.This study can not only optimize the terahertz test,more importantly,it lays the foundation for batch testing of the forage seeds,and provides an accurate experimental basis for the establishment of grass species identification database.Next,the 13 species of alfalfa forages from four different regions with similar climate environment were studied via terahertz time-domain spectroscopy(THz-TDS).The refractive index in the frequency interval of 0.2-1.2 THz was calculated as a characteristic parameter based on the frequency spectrum,where the maximaldifference reaches approximately 0.2.To illustrate the interspecific relationship,principal component analysis(PCA)was implemented using the refractive index.According to the first two principal components,genetic factors-regardless of origins-mainly contribute to the distance of the dataset.In hybridization,the PC score of the cross is determined by its parents,while exchanging male and female parents has impact on the conclusion.Plants with similar genes that were cultivated in similar environments(including sunshine time,precipitation,and temperature)tend to have identical PC scores.In summary,this paper combines the terahertz test results of forage seeds with their biological characteristics and genetic essence through terahertz time-domain spectroscopy and multivariate statistical methods,in order to make more in-depth use of terahertz technology for forage seeds.And the basis for identification and research on interspecies differences of forage seeds has been laid in this paper.