Effects Of LcAPX On Plant Cadmium Resistance And Optimizing Of Rice Callus Culture Condition

The LcAPX transgenic line was selected after PCR and RT-PCR analysis.The transgenic plants were used as the materials in the research and the non-transgenic tobacco plants were considered as control group.Some physiological and biochemical indexes ranging from the activities of certain enzymes to phenotype characters were measured.Based on statistical analysis,the result illustrated:1.Transgenic tobacco plants showed higher tolerance to reactive oxygen species.Cadmium pressure led to the accumulation of excessive hydrogen peroxide.Compared with non-transgenic plants,the APX activity is higher in transgenic plants,which contributed to a higher capability of scavenging hydrogen peroxide within the plants.Under the treatment of cadmium,transgenic plants accumulate less MDA.Also,the enzymes associating with the antioxidant system in transgenic plants were more sensitive to the cadmium treatment.When plants subjected to cadmium pressure,SOD and POD activities in both transgenic plants and non-transgenic plants were increased.Under the Cd pressure,the SOD and POD activites in transgenic plants is significantly higher than the ones in non-transgenic plants.2.Under the cadmium treatment,the cadmium stress tolerance of transgenic tobacco plant was enhanced significantly.Under cadmium treatment,stomata aperture of transgenic plants is larger than the once in non-transgenic tobacco plants.The effects caused by cadmium pressure were less in transgenic tobacco considering the measurement of root length,stomata aperture as well as the germination rate.To sum up,the over-expression of LcAPX enhanced the cadmium tolerance in transgenic plants.Meanwhile,the total carotenoid contents were measured.The result showed that the transgenic plants accumulated more carotenoid,compared with the control group.The accumulation of lutein and zeaxanthin in transgenic plant is more than the ones in control group.Also,the callus culture technical system was established and the optimized,which included the conditions of rice seeds sterilization and bacteria-elimination,the effects on the rice callus induction rate caused by different concentration of 2,4-D and the differentiation rate of callus under different culture time.