Genetic Diversity Analysis Of Amygdalus Mira Koehne Kov. Et Kost Germplasm And The Physiological Response To Drought

Amygdalus mira Koehne Kov. et Kost belong to Rosaceae and Amygdalus from China. It has strong characteristics such as drought tolerance, disease-resistant, update easily. Although Amygdalus mira Koehne Kov. et Kost rich deposit in Tibet region, but lack the system research of germplasm resources, AFLP markers technique was used to study its germplasm genetic diversity, as to provide theoretical basis for effectively protect Amygdalus mira Koehne Kov. et Kost germplasm resources. In this study,13pairs of primers were screened out of95samples of genetic diversity in the analysis,319polymorphic bands amplified, analysis between samples polymorphism is100%, at the same time analyzed Na, Ne, H, and I of95samples each site and found Amygdalus mira Koehne Kov. et Kost group has a rich genetic resources, clustering results and PcoA analysis similar to the results, there is a certain degree of gene flow between the samples, therefore, Amygdalus mira Koehne Kov. et Kost can be applied as a basis peach breeding material.In order to study the ability of its drought-resistance, this study designed different drought time gradient, respectively for0days,6days,12days,18days and rehydration. The physiological and biochemical indicators of the samples were measured and analyze the drought-resistant mechanism. Explain the relationship between physiological indicators and drought-resistant mechanism from the different degree of drought for future research of resistance and popularization of drought-resistant varieties provide a theoretical basis.Under drought stress, The morphology of the plants is not affected greatly. The plant growth and leaf relative water content decreased slowly, Not only reduces the consumption of biomass, but also ensure the plants have enough water to maintain the growth of plants. Watered again, leaf relative water content increased and rapid return to normal level. Reactive oxygen species and MDA content increased in water-stressed plants, they could have toxic effects on plants. Higher antioxidant enzymes (CAT, POD, SOD, APX, MDHAR, DHAR and GR) activity can detoxify quickly and more effective, in order to reduce the plasma membrane damage. Stress was relieved, reactive oxygen species and MDA concentration, antioxidant enzyme activity is reduced, recovery quickly.The same time as the intensification of drought stress, Chlorophyll content、RuBPCase and PEPCase activity increased to ensure the smooth progress of the process of photosynthesis, enhance the metabolic activity of the plants. RuBPCase activity at least10times higher than PEPCase activity. It was proved that plant is photosynthesis by C3pathway, C4pathway did not play a role of resistance to drought stress.