Influence Of High Voltage Electric Field Treatment On Water Transport Law Of Seeds During Germination

Seed respiration,metabolism,and nutrient state of cytosol are closely related to its internal water transport process,and the water transport law affects the speed and quality of seed germination.High-voltage electric field treatment will affect the water migration law during seed germination.Reasonable high-voltage electric field pretreatment can improve the vigor of seeds in the early stage of germination.It is of great significance to reveal the mechanism of seed vigor improvement and determine the optimal electric field parameters.In this study,No.2 Daohuaxiang was used as the experimental rice seed,and the variation laws of germination rate,water absorption rate,bound water,free water,and semi-bound water were analyzed by low-field nuclear magnetic resonance,high-voltage electric field treatment,and standard germination test.The internal water transport mechanism of the treated seeds lays a theoretical foundation for the research on the improvement of seed vigor by high-voltage electric field treatment.The main research contents and conclusions are as follows:(1)Single factor test was used to soak the rice seeds under different electric field conditions for 24 hours,and analyze the changing laws of relative water absorption and water absorption rate during the water absorption process of seeds.The test results showed that the treatment of a high voltage electric field would reduce the two indexes of rice seeds,making them enter the germination state earlier.When the electric field is a pulsed electric field,the intensity is 200k V/m,and the treatment time is 20min,the two indexes of seeds have the most obvious downward trend.(2)Using a single factor test and using low-field nuclear magnetic resonance technology,the data in the relaxation spectrum of the transverse relaxation time of the rice seeds treated with different electric field conditions during the 24h water immersion process were analyzed,and the water and changing trend of total water,and the changing trend of the end time of the free water and bound water peaks were examined,and the prediction of seed vigor was discussed.The experimental analysis results show that the electric field treatment can reduce the total water content and bound water content of seeds,increase the free water content of seeds,and make the water ratio fluctuate in a wide range.Among them,the electric field type is the pulsed electric field,the electric field intensity is 200k V/m,the electric field condition is 20min,and the moisture content inside the seeds changes the most.And the experiment also found that the rice seeds treated by the high voltage electric field had an earlier end time of the bound water wave peak and a later end time of the free water wave peak.Under the above electric field conditions,the changes in the two indicators were the most obvious.Seed vigor is the best,so it shows that the two can predict the vigor of seeds.(3)Through combined experiments and low-field nuclear magnetic resonance technology,the data obtained from the relaxation spectrum of the transverse relaxation time of rice seeds treated with different electric field strengths and treatment times during the germination process were analyzed the changing laws of water.The test results showed that the peak of the bound water of the rice seeds treated by the high voltage electric field shifted to the right during the germination period,the amount of bound water decreased compared with the control group,and the amount of free water increased compared with the control group.Combined with the early disappearance of the water peak,it shows that the high-voltage electric field can speed up the conversion of water and make it enter the germination state in advance.The treatment group L5 in the test performed the best,with the corresponding electric field strength in the range of 120k V/m-161k V/m and the treatment time in the range of 13.05min-32.50min.(4)The effect of electric field strength and treatment time of high-voltage pulsed electric field on rice seed germination was studied by using the two-factor quadratic general rotation combined experimental design method.Perform dimensionality reduction and modeling optimization.The experimental results show that the treatment of a high-voltage pulsed electric field significantly affects the germination vigor of rice seeds(p<0.05);the model determination coefficient R~2 is 0.9940;the optimal conditions of the high-voltage electric field obtained from the model analysis are that the electric field intensity is 150k V/m,and the treatment time is 22.75min.The germination index Z was 4.09.(5)Using low-field nuclear magnetic imaging technology,the dynamic monitoring of the internal water transport law during the germination of rice seeds treated with a high-voltage electric field was carried out.The grayscale images collected by nuclear magnetic resonance are processed into pseudo-color images after unified mapping,which more intuitively shows the changes in this process.The test results showed that the moisture of rice seeds moved from the outside to the embryo of the seed in the early stage of germination,and then moved from the embryo to the nutrient-requiring organs of the seed after entering the germination stage.Compared with the untreated control group,the treated group entered the germination stage and the germination stage on the 2nd and 5th day,respectively,and the embryo viability always maintained a high level.