Study On Electrical Impedance Spectroscopy Of Rice Leaves Under Low Temperature Stress

Rice is a thermophilic crop,and the change of temperature has a great impact on it.The harm of low temperature is a big threat to rice production,which can cause obvious yield reduction or even no harvest of rice,often causing huge economic losses.Breeding healthy seedlings is an important part of rice production.The quality of seedlings can directly affect the quality and yield of rice.However,the cold resistance of rice in seedling stage has not been reported.In this experiment,the electric impedance spectrogram method was applied,and the corresponding equivalent circuit model was selected in combination with the internal structure of rice cells,to study the electrical characteristics of rice leaves in seedling period under low temperature stress,and the regression model was established with the data measured by electrolyte exosmosis method.The results showed that the method could be used as a new method to detect rice leaves in seedling stage,which was convenient,rapid,accurate and nondestructive,breaking through the traditional method.The main research results and conclusions are as follows:The parameters needed in the test are determined and the clamping device is designed.The clamping device has simple design,low cost and can control the contact area between the sample and the electrode in the test process,use pure copper wire with shielded wire to connect the impedance detection systemThe location of rice leaves in seedling stage was determined and the difference was analyzed.The results showed that the widest part of the inverted blade had the best stability.In the same batch of seedlings,take any one rice seedling for testing,the measured results can represent the whole batch of seedlings.The impedance pattern of rice leaves in seedling stage is complete,symmetrical and single semi-arc,which is suitable for Cole-Cole equivalent impedance model.Under low temperature stress,the rice seedlings under 0 ?,4 ?,respectively-8 ?,10 ? in dealing with 0 to 8 h,measuring the electrical impedance spectroscopy.The results show that when rice leaves are subjected to reversible damage,electrical impedance pattern is a complete,symmetrical,single half arc;after irreversible injury,the left side of the arc starts to disappear;rice tended to die when the arc on the right side of the impedance spectrum began to scatter.The change of electrical impedance spectrum was consistent with that of relative conductivity.When rice was not dead,the extracellular resistance and relaxation time of leaves decreased with the increase of stress degree,intracellular resistance increases.Electrical impedance spectroscopy method can replace conductivity method to detect physiological characteristics of rice under low temperature stress.In addition to the significant difference in temperature between intracellular resi stance and relaxation time,the difference in stress degree between extracellular resistance and relaxation time was extremely significant.Logistic function can well fit the change of rice leaf extracellular resistance,that is,extracellular resistance is the most suitable parameter to determine the cold resistance of rice leaf after freezing treatment.In conclusion,electrical impedance spectroscopy can replace electrolyte exosmosis to detect physiological characteristics of rice seedling under low temperature stress.The test results were accurate,the process was simple,convenient and fast,and no damage was done to rice leaves.This study provided a basis for the study of physiological status of rice under low temperature stress by means of electrical impedance spectroscopy.