Japonica Rice In Cold Genetic System Optimization And Differentiation Physiological And Biochemical Characteristics

Rice is one of the most important grain crops in the world, which is widely cultivated and in great demand. Heilongjiang Province is the main production area of high quality japonica,it is the important commodity grain base of the country. The cultivated area of japonica rice in Heilongjiang is large, because of the narrow japonica germplasm resources, which limited the replacement of the rice varieties. The genetic improvement of rice had very important economy and social significance by using modern biotechnology, as the complexity of the rice callus regeneration process that were effected by many internal and external factors, the japonica tissue culture regeneration efficiency is low, limited the japonica rice genetic improvement research process. In this experiment, three varieties of Japonica rice in cold region Longdao9, the Changbai3, Dongnong427were used as the materials to study the in vitro culture media types, the effect of the media types and Hormone kinds and their concentration and copper ions for the rice mature embryo regeneration system and the physiological and biochemical characteristics of differentiation medium,in order to improve the rate of regeneration of rice callus, enrich understanding of the occurrence mechanism of the plant somatic morphology. The results are as follows:NMB medium (N6medium composition+MS trace element+B5organic ingredients) sign-ificantly increased callus induction and differentiation rate, and role in the induction and subcu-lture.The result indicated that the optimal medium for Changbai3and Longdao9induction was NMB+3mg·L-12,4-D+1.5mg·L-16-BA, while NMB+3mg·L-12,4-D+1mg·L-16-BA was for Dongnong427, and the induction rate of three rice mature embryos was increased from49.00%、42.50%and68.01%to87.50%、91.30%and81.20%, respectively. With the optimal subculture medium of NMB+0.02mmol·L-1Cu2+, browning rate of Dongnong427and Longdao9was decreased from51.85%and29.41%to23.61%and14.28%. But NMB medium containing0.01mmol·L-1copper ions was the best subculture medium for Changbai3, and the browning rate decreased from43.24%to21.60%. The best suitable differentiation medium for Changbai3and Longdao9was N6+3mg·L-16-BA+1mg·L-1NAA+0.02mmol·L-1Cu2+, however, N6medium including3mg·L-16-BA,1mg·L-1NAA and0.01mmol·L-1Cu2+was the best optimal differentiation medium. The differentiation rates were raised from12.9%,12.5%and2.38%to67.86%,28.87%and33.65%. Different hormones and copper ions media had great influence on differentiation rate of callus, The highest differentiation rate was the differential medium added copper ion and6-BA hormone, adding of hormone6-BA was higher than adding of hormone KT. The differentiation rate of the different treatment and different varieties were different and the differentiation rate of callus was influenced by genotype.There were differences in the MDA content among different treatments during differentiation of callus. MDA content showed double-peak curve in the CU processing, with the peaks appearing in6d and12d after callus differentiation,6d to reach the maximum; under K treatment and B treatment the MDA content showed a single peak curve, the peak time of different varieties was different.The proline content showed a single peak curve during differentiation of callus, with the peak appearing in12d, the proline content increased with differentiation time,12d to reach the maximum and decreasing afterward; the CU processing prolinol content is higher than other treatments.The Soluble protein content showed double-peak curve during differentiation of callus, with the peaks appearing in6d and12d after callus differentiation,12d to reach the maximum; the peak value of CU treatment was significantly higher than treatment B and treatment K, and B treatment higher than K treatment.Superoxide dismutase (SOD) activity during callus differentiation among the treatments were different, SOD activity in the CU processing a single peak curve, the peak in6d. SOD activity in the CU treatment was significantly higher than the other treatments, different hormone treatments callus SOD activity was not obvious.Peroxidase (POD) enzyme activity in the differentiation of the callus showed a single peak curve, the peak in12d, with the differentiation time progresses, the POD activity was significantly increased,12d reached the maximum, decline; CU deal with POD activity than treatment B, B treatment is higher than K treatment.Catalase (CAT) activity in callus during differentiation of a bimodal curve peaks appear in the Od after the callus differentiation and6d, Od to the maximum. After the first9d activity to maintain a certain level. Among the different treatment, the CU processing activity was significantly lower than the other two treatments. Treatment B and K treatment is not obvious. The soluble sugar content during callus differentiation in a single peak curve, a rapid increase from the first Od,6d maximum, then decline rapidly,12d minimum value, and then to rise slowly. CU processing and treatment B no significant difference between the CU processing and treatment B were higher than K treatment.Glutamine synthetase (GS) activity in the differentiation of callus showed a single peak curve,6d maximum, followed by rapid decline in12d after leveling off. GS activity in the callus differentiation among the treatments were different, the CU processing GS enzyme activity than treatment R R treatment was greater than K treatment.