| Root plays an important role in the crop soil moisture absorption process, as the main organ of the moisture absorption, the moisture absorption and maize resistance to drought stress adaptation is closely related. This study using hydroponics, paraffin section, optical microscope observation, choose 14 maize inbred lines, using PEG-6000 simulated drought stress, determination of seven closely related with drought resistance root traits of maize inbred lines at seedling stage, and by analysis of variance, correlation analysis and cluster analysis, comprehensive evaluation for drought resistance of inbred lines, selected two obvious differences in seedling roots at water and water stress, drought resistant materials Wu 109 and drought sensitive material WN897. By the method of paraffin section and microscopic observation for the genetic analysis of seven indicators of seedling roots, in order to provide theoretical basis for relevant aspects of seedling roots of maize drought resistance breeding research. The results were as follows:(1) maize seedling root elongation rate at water stress conditions, root dehydration rate decreased,the decline between inbred lines is in different amplitude, the root elongation rate of the inbred lines with strong drought resistance ability decreased small, root dehydration rate decreased significantly; with increasing tilt angle, the water potential gradient increases, to the water bending amplitude also showed varying degrees of increase, the drought resistant inbred lines to the water bending increased significantly.(2) water stress can lead to the anatomical changes in the structure of root, the root cortex width of inbred lines is in varying degrees of decline, the ratio of root cortex width to root diameter decreased to different extent,the root vessel diameter to reduce overall, the root cortex width of drought tolerance inbred lines is thin, cortex accounted for a smaller proportion of root diameter, root vessel diameter is smaller.(3) the responses of the indexes to water stress were different, in which the proportion of root diameter, cortex thickness and water loss rate of the cortex were affected.According to the results of drought resistance(D), the 14 maize inbred lines can be divided into Strong resistance,Moderate resistance,Han min, and Gao min 4 levels of drought resistance. Poly into class I mainly Wu 109, Chang 7-2, zheng58, PH4 CV, Mo17, into poly class II mainly PH6 WC, WN75, WN44, and 4, mainly clustered into class III 803, 138, WN180, WN104 and clustered into IV have WN897.(4) genetic analysis of root traits under water stress conditions:Under water stress the root hydrotropism bending, the root cortex width best genetic model is the D model, which is a pair of additive dominant major genes plus additive dominance epitasis polygene model; under water stress, the ratio of root cortex width to root diameter,the root vessel diameter,the root dehydration rate,the root diameter under condition of water and water sress optimum genetic model is the E model, which is two of additive dominance epistasis major genes plus additive dominance epitasis polygene model; under normal conditions, the root hydrotropism bending, the root cortex width, the ratio of root cortex width to root diameter, the root vessel diameter, the root dehydration rate,the root elongation rate under condition of water and water sress best genetic model is E-1 model, which is two additive dominant epistasis major genes plus polygene mixed genetic model. Normal and water stress conditions root cortex width, Ratio of root cortex width to root diameter, root elongation rate and root dehydration rate in BC1, BC2 and F2 populations showed relatively high heritability, genetic stability, root hydrotropism bending, root vessel diameter genetic rate is low, the genetic stability is poor, but in the BC2 population has the high efficiency of genetic. The genetic efficiency of root diameter was lower and the heredity could not be stable. |
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