Research On Poplar Psychological Health Detecting Techniques Based On Chlorophyll Fluorescence Spectral Analysis

Laser-induced fluorescence spectroscopy can monitor the physiological status of plants rapidly, conveniently as well as intactly, thus, it can help to realize the accurate information management, digitization of agriculture. By analyzing the current research situation of applying the physical health system of poplar and fluorescence spectroscopy to the study of the physiological status of plants, this study comprehensively combines multi-disciplinary knowledge to solve a number of crucial technical problems based on the chlorophyll fluorescence analysis. In addition, this provides referential evidence to the rapid diagnosis of the physical health of poplar.The main contents are as follows:â‘ The outdoor cultivation of poplar is the research object, in the red (660nm), blue (473nm) of two different wavelengths, 2.5mW, 5.0mW, 7.5mW, 10.0mW four different intensity of the laser, the fluorescence spectra of poplar leaves data collection and analysis of different wavelengths of light intensity under different excitation fluorescence spectra excited by the spectral characteristics of the situation is suitable for analysis and discussion of experimental results, the final optimum excitation wavelength and intensity;â‘¡The outdoor cultivation of poplar for the experiment and derived optimum excitation light as the light source to study the different spectral pretreatment methods on the impact of spectral model;â‘¢The potted seedlings poplar as the research object in the artificial climate chamber through the control variables, each set a different temperature gradient, illumination time and intensity, and CO₂ concentration, analysis of the physiological effects of poplar and chlorophyll fluorescence spectra of poplar characteristics, and the establishment of forecasting model;â‘£The outdoor cultivation of poplar seedlings and poplar as the research object, both subjects were nitrogen and water stress, respectively, experimental, experimental analysis of stress on physiological indices of poplar, spectral parameters obtained with nitrogen and water forecasting model;⑤Environmental factors and the nitrogen and water stress experimental method of removing the abnormal samples, and samples removed after the optimization of the experimental test data analysis, the diagnosis of poplar threshold of physical health, physical health to establish the best diagnostic poplar forecast model;â‘¥Using the Visual Basic object-oriented languages, the establishment of poplar based on chlorophyll fluorescence spectrometry diagnostic system software, including document management module spectrum, spectral pre-processing module, real-time information control module, populous physical health diagnosis module.In this paper, the laser as the excitation light source, directing exposure to excitation of chlorophyll fluorescence in leaves of poplar. The following conclusions are arrived at:1) Determine the intensity of 7.5mW laser-based experimental analysis of the best Blue-ray excitation;2) The second poplar as the experimental object, the day of poplar leaf photosynthetic active radiation (PAR) and fluorescence parameters Fv, Fm, Fv / Fm, SPAD, and fluorescence spectra of the peak wavelength of 675nm and 755nm bit of strength ratio, and ultimately determine the fluorescence spectra obtained for the SPAD value of the effective parameters, Fv/Fm and fluorescence spectra of 685nm and 735nm wavelength peak intensity ratio, obtained fitting their relationship with PAR:SPAD and photosynthetic active radiation (PAR) of the relationship: y=8.94838x2+4.97337E-4x+65.05734(R2=0.70086,SD=2.9867); the relationship between Fv/Fm and PAR: y=-4.41903E-7x2+4.97337E-4x+0.70771(R2=0.85672,SD=3.4325); fluorescence spectra of 685nm and 735nm peak wavelength, the intensity of the relationship between ratio and PAR: y=-9.26192E-8x2+2.13452E-4x+0.4597(R2=0.80248,SD=2.1246);3) Collecting the second time in the greenhouse experiment the spectrum of poplar leaves, number of digital SPAD detector measured SPAD values of the samples of poplar leaves, three points for each experimental sample test, and then their average as the final result the test results based on log (1/R) to express. The original spectra, first and second derivative spectra after MSC and SNV, the model predicted a significant change. Visible spectrum for the pretreatment of poplar leaves, the first order differential treatment RMSEC and RMSEP values of the best;4) Through experimental exploration of the atmosphere temperature, light intensity, CO₂ concentration in different situations on the physiological status of poplar and poplar leaves at different nitrogen levels, temperature and changes in photosynthetic capacity. Determine the optimal temperature range of poplar growth was 25 30℃, temperature and relative chlorophyll content of poplar curve fitting, cubic polynomial equation:y=0.48034x3-40.16107x2+1117.383x-10313(R2=0.78421,SD=1.29677). The relative content of chlorophyll values increased with time of illumination, the illumination time has a positive correlation with the relative content of chlorophyll. In addition, the curve was showed the positive correlation and after the linear fit, there has been the relative light intensity and chlorophyll content of the mathematical model equation:y = 3.4869x+14.97143(R2=0.90298,SD=3.55906);CO₂ concentration on photosynthesis in poplar leaves is a saturation point, beyond this restriction, the photosynthetic rate will fall in the growth of poplar leaves to play the role of inhibition.5) Nitrogen is the physical health of the main factors of poplar, so we study with poplar nitrogen between fluorescence spectra of F765/F675: y=9.904x2-4.231x+1.487(R2=0.8012,SD=3.0153); Soil moisture to reach between 21.0% 21.9%, the leaf water content reached the maximum. In addition, the nitrogen affects directly or indirectly the efficiency of photosynthesis, the chlorophyll content, photosynthetic rate, dark reaction and photorespiration, Soil moisture content is between 21.0% 21.9%, the highest peak in leaf water content, the efficiency of water usage is at the highest level. Irrigation and poplar leaf water content of the fitting curve equation:y =4.40406E-5x2 +4.40406E-5x +0.8369 3(R2=0.97499,SD=2.1352);6) Physical health diagnosis system constructed of poplar, fluorescence spectra can be achieved on-line acquisition, real-time spectral preprocessing, model selection algorithm, the relevant physiological information (water content, nitrogen content) of the acquisition, the diagnosis of physical health poplar and the growth of the current status of poplar response functions. Extended the feasibility of applying the poplar forest fluorescence spectroscopy to plant's physiology diagnosis.