Dissertation > Biological Sciences > Botany > Plant Biochemistry

Electrochemical Monitoring of Signal Molecule of Plant in Vivo

Author YangQin
Tutor ZhaoYuanDi
School Huazhong University of Science and Technology
Course Biomedical Engineering
Keywords Peroxide Nitric oxide Electrochemical Integrated micro electrode Plants in the body to detect
CLC Q946
Type Master's thesis
Year 2011
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Exist a lot of signaling molecules such as hydrogen peroxide, nitric oxide, etc., between them to each other synergies, mutual adjustment, regulation of the physiological activities of the plant in the plant body. Therefore necessary to adjust the amount of the active oxygen of the hydrogen peroxide has strong oxidizing as well as cytotoxic has a certain reduction of nitric oxide, but when the concentration is too high, the same toxic effects on biological has a larger within a certain range; . When the plants are biological or abiotic stress, the body of reactive oxygen and nitric oxide levels change common role in plant pathogen defense system. Well, these signaling molecules probing plants of great significance to study plant life activities. The electrochemical biosensor detection convenient quickly without additional tracer molecules, the electrode probe easy miniaturization, equipment cost and low detection, but also continuous monitoring of these small molecules in the concentration of plants, not only can the organism changes. The main subject of the use of electrochemically modified electrode Hydrogen Peroxide Sensor and nitric oxide sensors were prepared and applied to plants in vivo monitoring. The main work of the following: (1) using cyclic voltammetry in platinum micro-particles of platinum micro-column electrode modified with electrodeposited o-phenylenediamine, obtained peroxide hydrogen sensor has a good electrochemical performance. Measured won between hydrogen peroxide-0.1V potential reduction current and concentration showed a good linear relationship (R = 0.995), and a detection limit of 25 μmol / L. The use of the hydrogen peroxide sensor monitored Rape by oxalic pathogenic factor infestation, different parts of the hydrogen peroxide generated in the body. The experimental results show that when the rapeseed plants by oxalic Stress, will produce the outbreak of the two large amount of active oxygen, the intensity and duration of the second outbreak are much larger than the first. First major infected a large number of cells surrounding the generation of reactive oxygen species, used to control pathogens continue wide bulk; outbreak of the second oxygen plants under stress, self-defense system of regulation produced greater strength and duration The longer active oxygen outbreak. (2) the use of poly-o-phenylenediamine and Nafion membrane coated graphite electrode modified After tetrasulfo NiPc (the GE / NiTSPc / POPD / Nafion), made from nitric oxide sensor. On the working electrode in the working voltage of 0.8V, nitric oxide has a larger oxidation current detected when nitric oxide concentration in 0.7μmol/L-8μmol/L between the current and the concentration of the oxidation has good a linear relationship (R = 0.995). Nitric oxide sensor of ascorbic acid (AA), sodium nitrite (NaNO2) and hydrogen peroxide (H2O2) has better anti-interference effect. When tobacco by UV stress, the nitric oxide sensor detects changes in the level of nitric oxide in the body. (3) after the insulating treatment of the platinum wire and silver epoxy encapsulation, the silver is formed by etching a hole in the capillary, made of the indented type Ag / AgCl reference electrode. The integrated micro-electrode has a good reproducibility, measured eight times the standard deviation of about 0.0032 of its potential. After that we in the integrated micro-electrodes on the working electrode modified dispersed platinum particles o-phenylenediamine, the system too hydrogen peroxide sensor, and successful use of it in the body monitoring the reactive oxygen species generated plants infested outbreak . This work was supported by the use of electrochemical methods to provide a new method for biological detection.

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