Research Of Magnetized Arc Plasma On Seeds Biological Effects

Plasma is called the fourth state of matter, which has been used widely in electron, material and environment, etc. In 1980s, the biological effects of the early seedlings were studied after the seeds treated by ion implantation technique in Dalian university of technology. The transferring-gene, variety improvement, sterilization etc. by ion implantation method have gained economical benefit in institute of plasma physics of CAS.Heredity is controlled by genes, but their expression is turned on and off throughout life depending upon biotic and abiotic factors in environment. Most of genes was usually in silent and could not express. The crop yield could be improved by some outside stimulating, which promote genes expression, improve the stress resistance and accelerate plant growth. The ozone, strong ultraviolet, excite oxygen, free radicals and magnetic field in the magnetized arc plasma could promote seed germination and seedlings growth, improve stress resistance and alleviate plant diseases and insect pests, so the yield could be improved. In this study, the seeds of wheat, tomato and soybean were treated by the magnetized arc plasma, and the shape, physiological parameters, yields structure, free radicals, and sterilization effects were analyzed. The main results as follows:1. The magnetized arc plasma produced distinct stimulating effects for the wheat, tomato and soybean. It could promote seed germination, seedling growth and improve yield: the fertile tiller in wheat increased obviously and the yield improved by 10.51%~19.73%;the 1.5A treatment increased the tomato yield by 20.7% and the fruit number increased was the main reason of yield improvement;the soybean yield improved by 9.36%~ 16.99% and the dominating factor of yield improvement was enhancement of bean-pod number.2. The optimum treatment dose exist a range in tomato and soybean. The better range of tomato was 1.0~2.0A, and the optimum point was 1.5A;there existed a obvious effects in the range of 1.0-2.5A which was a wide range for soybean, and the optimum range was 2.0~ 2.5A. There were two ideal treatment doses, which were 1.0A and 2.0A in wheat. So the best treatment dose in different crops has different regulation. POD isoenzyme is controlled by monogene and changes with environment sensitively. The biological effects of different variety in three crops were compared using POD isoenzyme, the results shows that the optimum treatment dose presented biggish difference.The optimum treatment doses in different crops were approved from respiration, energy and enzyme activity. The change regulation of physiological parameters was consisted of the shape parameters primarily. It was interesting that the sensitivity of roots andleaves/hypocotyls was also different for the magnetized arc plasma.3. The wheat and tomato seeds treated by the magnetized arc plasma germinated under the common conditions. After the seedlings stressed using PEG-6000, SOD, POD activity increased obviously and MDA content declined, which indicated magnetized arc plasma could enhance the drought resistance of plant.4. The stimulating effects on the plant of ionization radiation are relative to the free radical concentration. In this study, we determined the changes of free radical concentration of Sesamum indicum seeds treated with magnetic field, electric field and arc plasma by ESR (Electron Spin Resonance, ESR) spectrum method. The free radical concentration of Sesamum indicum increased with the magnetic field strength and peaked at 82.5mT and then decreased after the sesame seeds were treated by different current strength for 30 min. With the increasing of treatment intensities/time of electric field and arc plasma, the free radical raised continuously.Free radical concentration of sesame seeds treated by magnetic field and arc plasma declined with the storage period. However, the decrease regular of both treatment ways was different: the free radical concentration declined with the storage time almost become a line trend when the seeds treated by magnetic field and present a quick at first and then slow process when the seeds treated by arc plasma. In electric field, the free radical was steady relatively.5. Ozone, ultraviolet, and active particles etc. in the arc plasma could sterilize the fungi and bacilli effectively. In our study, the Ustilago crameri Koern, Ustiago maydis, Sporisorium reilianum and some fungi in cucumber cultured in PDA media, could be sterilized effectively in 4 seconds. The seeds treated by arc plasma for 30s, lmin, 2min, 5min, and the sterilizing effects were appraised in the PDA media. The results show that it was difficult to sterilize the seeds compared with the surface disinfection, while the disinfection rate was about 90%. The sterilizing effects for the three crops seeds were different: the soybean was the easiest and the second was wheat, then the tomato seed was the most difficult. Maybe this was relative to the lubricity and shape of seeds surface.6. The results of organophosphorus and carbamic pesticide degradation by arc plasma show that solvent polarity and initial concentration of pesticide affected the degradation rate. The detailed results as follows: the degradation rates in different solvent for the two organophosphorus and pesticide are listed in the following order, i.e., water >methanol/acetonitrile >acetone >acetoacetate, however, the order of degradation rates for carbofuran in different solvents was acetoacetate >acetone > methanol >water.The half-life of four pesticide in different solvent are listed as follows, in water solvent: carbofuran>chlorpyrifos>monocrotophos>methomyl;in methanol and methanol: chlorpyrifos>carbofuran>monocrotophos>methomyl;in acetoacetate: chlorpyrifos>monocrotophos > carbofuran > methomyl. The half-life of the four pesticides was less than 10 minute, which attributed to the wide spectrum, strong UV and ozone of arc plasma. Arc plasma would degrade the pesticides residue in fruit and vegetable effectively.