Study on Optimization of Plant Regeneration System and Correlative Nitrate Metabolization

In order to study the feasibility of wheat mature embryos as explants for callus induction and plant regeneration,10 different genotypes commom winter wheat（Triticum aestivum）mature embryos were used under different culturing conditions of different medium and different treatment.In order to study the physiological characteristics of induction and differentiation in wheat mature embryo, activity of nitrate reductase and nitrite reductase about callus induction and differentiation was detected and their mechanisms were analyzed in this paper. For a further study on wheat regeneration mechanism, Callus long-term growth and subculture, Differentiation in the metabolism of nitrate and effect of Nitrate metabolism on wheat mature embryos differentiation were analysed. The purpose is to further study the effect of wheat mature embryo in dedifferentiation and redifferentiation,and provide a basis for analysis Wheat efficient regeneration system of mature embryos. The results showed that:1) The optimal medium for callus induction was MS+ dicamba basic medium; Low hormone levels to more embryonic callus rate and the low rate and high concentration of hormones can raise the rate more, the most suitable concentration of 2,4-D was 2 mg·L^-1.The average callus induction rates and differentiation rates were 83.89% and 15.83%.2) The impact of changing temperature treatment on callus induction: 4℃low temperature treatment on callus, then 34℃high temperature treatment. The average callus induction rates and differentiation rates were increased by 3.22% and 1.56%.3) The impact of sub-culture model on callus quality: Protective Effects of callus quality and I-IV alternating injection was more obvious.4) Differentiation of pre-treatment:The results showed that before plant differentiation calli were eluted 48h with shake culture plus 48h and dehydration 48h deyhation only increased plant regeneration frequency,speed up plant regeneration process. But their easily led to calli growing roots before calli germination. The function of speeding up plant regeneration course was enhanced by elution with shake culture plus dehydration .The average differentiation rate of 10 different genotypes is 16.20%. 5) The impact of nitrate nitrite reductase on callus induction:The results showed that the NO2-and nitrite reductase of the type II callus induction are stability, their growth, the rate of embryonic callus are stability too. The nitrite reductase of the type I callus induction is decrease,their growth, the rate of embryonic callus are decreased in the long-term callus subgeneration culture.