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DF Detection Technique And Its Application Of Photosynthesis Capacity And Stress Examination

Posted on:2008-10-13Degree:DoctorType:Dissertation
Country:ChinaCandidate:J S WangFull Text:PDF
GTID:1100360245996611Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
Delayed fluorescence (DF) phenomena can be described as light emission of photosynthetic organisms shortly after their illumination and only occurs in living cells. It is a good method of researching the effect of various chemical and physical factors in vivo and in vitro on photosynthetic performance of plants. At present, DF has wide application foreground in the research of biomedicine, agriculture, food industry, and environment and so on.DF has the advantage of the sensitivity to change of photosynthesis under normal physiology, salt stress and UV-B radiation stress and speediness of DF measurement. Based on the advantage, developing and establishing an in vivo and environmental(Temperature, Humidity and CO2 concentration) control DF decay kinetics detection technique and applying it in fast photosynthesis capacity detection, evaluating the extent of damage of plant physiology caused by the salt stress and UV-B radiation is of very important theoretical senses and practical values for fast identification of high photosynthesis rate plants, fast selection of new varieties of salt resistant plants, real-time monitering and fast examinatioin of plant physiology under UV-B radiation environmental stress that, at the same time, which provides theoretical and experimental basic for the application research of DF technique in the other domains.In the paper, DF decay kinetics technique is taken as core, DF decay kinetics detection method is studied and a system of DF detection suitable for plant leaf in vivo and environmental control is designed. DF quantitative method is studied by analyzing the characteristics of DF decay kinetics curve. On the basis of this, the theory, method and realization of using DF to represent photosynthesis capacity are researched. It is also investigated that the method of evaluating the extent of damage of plant physiology caused by the salt stress and UV-B radiation using DF technique. Main contents of this paper are as follows:Aim at the disadvantages of inaccuracy, limited application and less repeat owing to in vitro and without environmental control existing in the conventional DF detection technique, a method of DF detection suitable for plant leaf in vivo and environmental control is presented. At the same time data processing method of DF decay kinetics signal is proposed according to characteristics of DF decay kinetics.According to the principle of DF decay kinetics detection, based on the characteristics of DF excitation and emission and DF decay kinetics rule, a system of DF detection suitable for plant leaf in vivo and environmental control is designed. The system is mainly composed of the following parts: hermetic sample chamber in vivo, LED exciting light source, envioronment (Temperature, Humidity and CO2 concentration) control, electric control, Channel Photomultiplier DC-module, data acquisition and processing and so on. LED excition light intensity and regulable range and stability of environmental system are tested. The Signal Noise Ratio (SNR) of DF detection system is also tested.Based on the relations among DF intensity, quantum yield of the primary photochemical reaction in open PSâ…¡reaction centers, rate of PSâ…¡electron transport, limiting step of photosynthesis under the most optimal environmental conditions of saturated excitation light, optimal temperature and saturated CO2 concentration, a mathematical model of using DF to reprensent photosynthesis capacity is developed and conditions of correlation is confirmed. By analyzing the characteristics of the multicomponents decay kinetics model of DF, a simplified three components approximation decay kinetic model is proposed. Further the characteristics of simplified module is analyzed, quantitative method of DF is studied. Parameter optimization of DF intensity is researched and correlation database between DF intensity and corresponding photosynthesis capacity is established. Perfect the method of using DF to represent photosynthesis capacity and design fast photosynthesis capacity detection system based on this method. Field contrast experiments for measuring photosynthesis capacity using the developed system and commercial photosynthesis system LI-6400 is performed to demonstrate the veracity and rapidness of measurement of the developed system.A method for evaluating the damage extent of plant physiology caused by the salt stress using DF technique is presented. Effect of different concentration NaCl on DF intensity and photosynthesis rate is analyzed and change of DF time kinetics under CaCl2, 6-BA, SA stress factors is also researched. By these above experiments the correctness of the method using DF to evaluating effects of salt stress is demonstrated.A means of evaluating the stress on plants caused by UV-B radiation is presented. Effect of different UV-B radiation intensity on DF and chlorophyll content is researched. The effect of UV-B and white light together on DF and photosynthesis rate is analyzed and change of DF intensity by different UV-B radiation time is also studied. Thus the method of evaluating the stress on plants caused by UV radiation fast and in vivo using DF technique is validated.
Keywords/Search Tags:delayed fluorescence (DF), photosynthesis capacity, salt stress, ultraviolet-b (UV-B) sress, fast detection
PDF Full Text Request
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