Effect Of HVEF On Seed Vigor Of Aged Rice And Its Mechanism

High voltage electrostatic field (HVEF) is a kind of man-made effective field. Now, it has been certified that its energy can be absorbed by plants and promote the growth of seeds and crops. Seed vigor will inevitablely decline during the store.So it is significative to promote the seed vigor of aged seeds with HVEF. Aged rice seeds were chosen as the materials to study the effects of HVEF and its mechanisms. The study included seed vigor, physiological indexes, soluble protein, isoenzymes and cell division of root tip. The study covered four parts as follows: 1. Selection of parameters of HVEF The parameters of HVEF in this study included moisture content of seeds before and after HVEF treatment, electrical field strength and treatment duration.The results showed that the effect of HVEF on the dry seeds was inapparent. But the effect on wet seeds was highly significant.The aged rice seeds were soaked for 24 hours at 30℃(the moisture content was 40%) before the treatment, then the wet seeds were treated with HVEF and soaked for 24 hours at 30℃again and germinated. According to germination, suitable electrical field strength was 250-450kV/m and treatment duration was 30-55min. 2. The effect of HVEF on the physiological indexes of aged rice seeds (1) During the forepart of germination term (from the first day to the fifth day of germination), the root vigor of treated groups was 24.72%-48.23% higher than that of the control group, and the content of chlorophyl of treated groups was 3.46%-28.3% higher than that of the control group. The treated groups'conductivity of seeds leakage was significantly lower than the control group's. Appropriate HVEF could enhance the amylase activity. The increase of total amylase activity at the fourth day of germination was mainly due to the enhancement of β-amylase activity. At the fifth day of germinationα-amylase activity mainly enhanced. The CAT activity of seedling at the forepart of germination term was 7.78%-22.89% lower than control after treated with HVEF. However, HVEF treatment enhanced not only the POD and SOD activity but also the content of MDA. (2) During the evening of germination term (from the sixth day to the tenth day), the chloropyl content of treated groups was 11.68%-36.58%, which was higher than that of control. The treated groups'CAT and POD activity were higher than control too. The content of MDA decreased significantly after treated with HVEF. However the SOD activity of treated groups was inapparent with that of the control group. After the seeds were treated for 55 minutes by HVEF, the indexes were significantly discrepant with those treated for 30minutes. These indexes included total amylase activity, conductivity of seeds leakage, SOD activity at the forepart of germination term, and the content of chloropyl and MDA at the evening of germination term. 3. The effect of HVEF on soluble protein and isoenzyme of aged rice seeds (1) Suitable HVEF could increase the content of soluble protein of seedling at the forepart of germination term. Especially the soluble protein of roots increased evidently. (2)During the forepart of germination term, the number of piece and colour of electrophoresis map about treated groups'soluble protein of seedling and root was more enhancive than that of control. However, the pieces of soluble protein in leaves of the treated groups were inapparent to that of the control group. (3) After the treatment of HVEF, the electrophoresis map of amylase isoenzyme, peroxidase isoenzyme, superoxida dismutase isoenzyme and catalase isoenzyme in the forepart of germination term were inapparent compared with that of the control group. In the evening of germination term the catalase isoenzyme of the No.7, 8,10 of treated groups was one piece much than that of the control group. HVEF influenced the expression of catalase isoenzyme. 4. The effect of HVEF on the cell devision of aged rice seeds'root tip The mitotic index of root tip cell treated with HVEF was significantly 77%-169.4% more than control. It is mainly due to the increase of prophase. There was not the aberration of chromosome after the treatment of HVEF.