| Elymus L., an important poaceae plant, was widely distributed in China where there were many species, and was highly adaptable. According to the character of morphological variance and high adaptation, thirty-eight accessions of wild Elymus(two materials of E.sibiricus and E. dahuricus from the local as comparison)were collected and studied on geographical distribution, growth and development, morphological variation, anatomical structures, physio-ecological and genetic characteristics to reveal the ecological adaptation mechanism. The main results were as follows:1. The Elymus germplasm had rich morphological diversity. No matter nutritional organs, ear traits or seed characters all had a wide range of variation. The principal component analysis results showed that plant high, spike length, rachis length of the first internode, flag leaf width, the first spikelet length, floret number, lemma length and spikelet number, spike type, 1000-seed weight, seed width and seed length were the main traits that determined phenotypic variation among populations. Different characters had different diversity indices. Among of these, the diversity indices of plant height, flag leaf length, flag leaf width, the length from flag leaf to the base of spike, glume awn length and 1000-seed weight were higher than spike traits.This means the spike characters is not susceptible to environment condition.2. All Elymus materials could return green in middle or late April. All the tested accessions could vegetate well and had better adaptability to local eco-climatic conditions. But different materials had significant differences growth period under the same environmental conditions. The growth dynamics of plant height increased quickly from jointing stage to heading stage, while the leaf area increased quickly from tillering stage to jointing stage. The yield characterizes of the thirty-eight accessions were significantly different. The leaf and stem ratio of most accessions belonged to the range of 1.5-2.0. Through gray correlation analysis showed there were 13 germplasm performed well, 23 medium and 2 poor. NMC32, BJT37, QHD19, SXD36, XJD11, XJD15, XJS8, XJT2, XJE13 and XJD5 were the top 10 germplasm. They all gave higher performances and could be uesed in breeding and production first. The yield of plants had closely relationship with the ratio of fresh and dry yield, seed production and flag leaf length. 3. The drought resistance of Elymus from different habitats was investigated by using potted plants to simulate soil drought condition. The dynamic process of plant height, leaf area, relative water content, relative electrical conductivity, proline content, chlorophyll, SOD and POD, and other indicators related to the drought resistance were comprehensive evaluated by fuzzy to under the jurisdiction of function law under 21d of stress. The results showed that with the days of drought stress increased, plant height, leaf area, relative water content and chlorophyll decreased significantly, while the relative electrical conductivity, proline content, SOD and POD were increased distinctly. After analysis of the values of jurisdiction degree, the drought resistance of 38 materials were divided into three categories, XJS17, NMD30, XJD14 and XJD11 were weak drought resistance, NMD33 and XJT10 as susceptible, the others as drought resistance. Through correlation analysis selected indexes which had significant impact on drought resistance were the relative water content, leaf area,chlorophyll and relative electrical conductivity.4. The Elymus anatomical structure was no significant difference, but the quantitative index the characteristics of these structures in different materials varied apparently. One of the larger coefficients of variation was midrib thickness (38.706%). Then was leaf thickness (33.843%), and the smaller coefficient of variation was the number of epidermal cells (14.134%). Through the principal component analysis, the roles determine the morphological changes were as follows: vascular bundle diameter, leaf thickness, ratio between stomatal length to width, long cell, upper stomatal number, lower thick, veins thick, stomatal wide, duct wide, short cell and shape of anticlinal walls.5. Diurnal changes of eco-physiological and photosynthetic characteristics and environmental factors in leaves of three Elymus sibiricus forages from different regions were measuresd under dry farming.The results showed the diurnal variations of photosynthetic rates presented double peak. The phenomenon of"noon break"were obvious. Photosynthetically active radiation(PAR) had the greatest effects on the diurnal dynamics of photosynthesis rate (Pn),air temperature(Ta) had the greatest effect on the diurnal changes of transpiration rate (Tr).6. The genetic diversity of gliadin among the 36 specimens was tested by A-PAGE. The results showed that a total of 56 gliadin genotypes were separated through electrophoresis and polymorphism amounted to 92.801%. The coefficient range of genetic similarity was 0.376-0.946 with 0.311on average.Which showed rich genetic diversity of Elymus accessions. The total genetic diversity index indicated that approximately 52.33% of total gliadin variation occurred among populations. By means of ISSR, fourteen primer pairs were selected from 63 preparations and then used to analyze the plant materials. A total of 165 fragments were amplified from these 14 primers, of which 142 bands (87.571%) were polymorphic. The genetic diversity was 39.57% and 60.494% within populations and among Elymus respectively, The two ways all indicated the genetic variation among groups was the main sources of total genetic variation.The populations of Inner Mongolia and Xinjiang had higher genetic diversity index. The same geographical origin of the same populations could get together first. But there also were obvious inter-cross among different populations. This illustrated that there were complicated relationships among different germplasm.All these study results showed that the adaptive traits were consisitent with leaf anatomical structure, physio-ecological characteristics and cultivation. The Elymus germplasm had rich genetic diversity. Elymus plants had similar anatomical structure. Cluster analysis showed that Elymus germplasm material had convergence adaptation character. There were different degrees relevance among phenotypical characteristics, ecophysiological, genetic diversity and the five ecological factors (longitude, latitude, altitude, with an average annual temperature and annual rainfall). After a long-term evolutionary, Elymus plants formed the special structure, physiological and ecological characteristics and genetic mechanism that adaptated to environment. These results provided scientific basis for the protection and useness of the Elymus germplasm. |
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