Research On High Throughput Chlorophyll Fluorescence Imaging System Applied In Plant Physiology Detection

The improvement of agricultural productivity is crucial to the survival of mankind.In the context of the new era,it is urgent to accelerate the modernization and informatization in agricultural development.In the process of agricultural modernization,the rapid and accurate acquisition of crop physiological information is an important foundation for agricultural modernization.Collecting crop physiological information and diagnosing crop growth status using modern technology,can assist producers to make a decision,such as irrigation,fertilization and spraying operations,and further achieve the automation and intelligence of crop production.Chlorophyll fluorescence detection technology can fully reflect the photosynthetic status of plants.Almost all physiological conditions of plants can be expressed through chlorophyll fluorescence.At the same time,chlorophyll fluorescence can be used to characterize the living state of plant samples,which is unmatched by other plant physiological nondestructive testing techniques.The existing chlorophyll fluorescence detection device has a relatively small imaging area,which is not suitable for the detection of economic crops such as cucumbers and tomatoes.At the same time,the lighting design of the light source is not complete enough to guarantee the high energy utilization.Therefore,in this paper,the actual problems in the process of carrying chlorophyll fluorescence detection technology forward from laboratory studies to agricultural production has been studied,and a high throughput chlorophyll fluorescence imaging detection system has been put forward.Firstly,the design of high throughput chlorophyll fluorescence imaging detection system is studied.The system uses the square rod lighting module,in which the light is uniformly illuminated by the square rod,and the light spot is amplified by the relay lens.Through the arrangement of multi-modules,the uniform illumination of large area and high light intensity is realized,and the high energy efficiency is obtained.The control circuit is designed for different light intensity requirements in the modulated chlorophyll fluorescence detection.The circuit outputs different duty ratio control signals,and the design requirement is achieved on average light intensity through the regulation of the light-duty ratio of the light source.To achieve the movement of detection module,a combination of various movement mechanism is designed.The detection module can realize a larger scope of scanning imaging detection by the mechanism.At the same time,the real-time observation of chlorophyll fluorescence images and inducing chlorophyll fluorescence curve can be realized through the system software design.Finally,the performance of the system is tested,and the effectiveness of the system is verified by the detection of cucumbers under drought and nutrient deficiency.Further,this paper presents a plant physiological diagnosis method based on chlorophyll fluorescence detection and multispectral detection.Taking tomatoes as experimental materials,three kinds of stress of drought,nutrient deficiency and plant diseases are designed,and three physiological status indicators are proposed to diagnose these three kinds of stress.Through the plant physiological status indicator distribution curve and other statistical analysis,the change trend of chlorophyll fluorescence parameter images and relative reflectance parameter images is characterized.The validity of the pant physiological diagnosis method is verified.Based on the actual quantum efficiency and the maximum quantum efficiency of photosynthesis respectively,the correlation between them and the stress degree of tomato drought and nutrition deficiency is studied,and the degree of stress can be reflected by quantitative description.At last,the work is summarized and some possible research directions in the future are put forward.