Chlorophyll Fluorescence Monitoring And Seed Characters Of Caragana Korshinskii Under Different Soil Salinity

In this paper,21 shrubbery forests in Tuoketuo county are taken as the research area,Caragana korshinski Kom.As the test species,the different salinity environment of soil is taken as the starting point,and matlab2016,SPSS17.0,origin2017,image Proplus are used as auxiliary tools to explore the potential of Estimating Leaf Photosynthetic Efficiency(Fv/Fm)by hyperspectral reflectance,so as to identify leaf threats by remote sensing reflectance data The purpose of this study was to establish a hyperspectral model to monitor the changes of leaf photosynthetic efficiency(Fv/Fm)of Caragana microphylla in different salinity environment.The results showed that chlorophyll fluorescence,canopy reflectance spectrum,seed vigor and physical characteristics in the different salinity environment provided the theoretical basis for the breeding and propagation of improved varieties and the diagnosis and monitoring of plant growth.The main conclusions are as follows:(1)The different salinity gradient environment will change the physical characteristics of Caragana seeds,and the two-dimensional area,perimeter,diameter,roundness,length and width of seeds will decrease with the increase of soil salinity in different degrees.As a result,the increase of soil salinity will deform the seeds,and the higher the soil salinity is,and the greater the different salinity,the more obvious the seed deformation.Soil salinity can inhibit seed vigor and germplasm.According to the average value of membership function,the average value of each index of Caragana seed is the largest,the growth and development is the best,and the tolerance is the best in the non-salinized soil environment.(2)The fluorescence parameters of chlorophyll showed a certain difference to the increase of natural salinity gradient.The initial fluorescence(Fo)and non-photochemically quenched(qN)showed a significant increase with the increase of salinity.The maximum fluorescence(Fm),the maximum quantum yield(Fv/Fm),the actual quantum yield(Y),the electron transfer rate(ETR)and the photochemical quenching(qP)of PSII showed a significant increase with the increase of salinity The increase of salinity shows a downward trend.Using the grey correlation analysis method to analyze the correlation degree of salt and chlorophyll fluorescence parameters,we can see that the correlation degree of qP is the highest,Fm is the second,fo is the second,and Y is the lowest with different salinity.Salinity affected chlorophyll fluorescence parameters,leaf performance index PSII electron donor side,acceptor side and electron transport chain function of Caragana korshinskii leaves,which changed the dynamic curve of chlorophyll fluorescence induction from O-J-I-P to O-K-J-I-P.The normal function of photosynthetic mechanism of Caragana korshinskii leaves was damaged.(3)Using RBF and BP neural network to build the monitoring model of chlorophyll fluorescence parameters,198 groups of hyperspectral data collected in July 2019 were taken as samples,among which 168 groups were training samples,and the remaining 30 groups were taken as test samples.701-710nm were selected as hyperspectral band to estimate the most sensitive chlorophyll fluorescence of leaves.The predicted value of Fv/m from the model and the measured value were roughly the same,and the determination coefficient was 0.822,both of which were equal The square root error is 0.056,and the fitting equation of the measured value and the predicted value is y=0.9952x+0.0011.Therefore,RBF neural network model can make the spectral characteristics of Caragana korshinskii canopy better retrieve the light energy conversion efficiency(Fv/Fm)of PSII in different salt environments.