Studies On In Vitro Conservation Of Citrus Reticulate Blanco And Genetic Stability

Restricting conservation is a main method of plant germplasm in vitro preservation. The target of restricting conservation was to restrict the growth of in vitro shoots and reduce the frequency of subculture basing on the maintenance of genetic stability. In this research, seeding of Daguo-97 and mature stems of Yangxiao-26 in vitro culture were materials, in vitro culture of mature citrus stems and restricting conservation of Citrus reticulate Blanco were examined, and sutiable in vitro presservation methods were established for Citrus reticulate Blanco. The main results were as follows:1. The mature stem segments of Citrus reticulita Blanco were used as explants for buds induction and subculture culture on medium with different hormone combinations .The results showed that the best induction medium is MS+6-BA0.5 mg/L +KT0.5 mg/L + NAA0.1mg/L, The induction medium of sucrose concentration from 3% to 6% can solve the leaves of buds yellow, shedding problems; subculture proliferation medium of buds is MS+6-BA0.4mg/L+ZT0.1 mg/L+NAA0.05 mg/L, proliferation of multiple was 5.40.2. Survival rate of in vitro plantlets conserved 4 months with different temperature sealing material, light intensity were studied by orthogonal experiments , The results showed that best preservation conditions of Citrus reticulate Blanco was sealed by kraft paper and 2 layers of polyethylene film , 18℃,400lx light intensity.3. Effects of medium with different chemical elements or different concentration of sucrose of Citrus reticulate Blanco were studied. The results showed that mineral nutrition with low concentration, sucrose with high concentration could inhibit the plantlet growing in vitro. That suitable chemical elements and concentration of sucrose for plantlets in vitro of Daoguo-97 was 1?4MS+60g/L sucrose, Survival rate of in vitro plantlets conserved 6 months was 92%, and suitable chemical elements and concentration of sucrose for Yangxiao-26 mature stems was 1?2MS+60g/L sucrose.4. Effects of medium with different growth inhibitors on the survival rate and growth of in vitro shoots of Citrus reticulate Blanco were studied. The suitable inhibitor for Citrus reticulate Blanco was PP333, and its suitable concentration was 1mg/L. The survival rates of conservation for in vitro plantlets and mature stems were respectively 100% and 78%, Significantly higher than other treatments. 5. Compared the materials recovery growth of conservation with the control, no variation was displayed on the level of morphology, protein, peroxidase, which showed that the materials of Citrus reticulate Blanco conservation for 6 months remained well genetic stability, and it suggested the feasibility of restricting conservation to conserve Citrus reticulate Blanco germplasm.