【作者】 祁娟；

【导师】 徐柱；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2009， 博士

【摘要】 披碱草属(Elymus L.)植物种类繁多,分布广泛,生境多样,适应性强,形态变异较为复杂。针对披碱草属植物形态多变适应性强的特点,本文以6种38份披碱草属野生种质材料为研究对象(以来自试验地周边天然草原的披碱草和老芒麦野生种质为对照),从地理分布、表型、生理生态、解剖结构以及分子水平等方面进行研究,力求揭示披碱草属植物生态适应机制。主要研究结果如下:1.披碱草属植物野生种质材料具有丰富的表型多样性。营养器官、穗部性状和种子性状均存在广泛的遗传分化。据主成分分析得出,株高、穗长、穗轴第一节间长、旗叶长、旗叶宽、外颖长、内稃长、颖宽、颖芒长、穗型、种子宽、千粒重、种子长、穗宽、穗节数和颖芒长等16个主要特征是确定优异种质和居群间形态分化的主要指标。不同表型性状多样性指数差异较大,其中株高、旗叶长、旗叶宽、旗叶至穗基部长、颖芒长和千粒重的多样性指数较高,穗部特征性状指标的多样性指数较低。2.披碱草属植物野生种质材料在试验地气候条件下均能完成生育期,但不同种质材料在同一环境条件下生育期有明显差异。生长动态分析表明,株高于拔节期到抽穗期增幅较大,叶面积于分蘖期到拔节期增幅较大;不同种质材料牧草产量差异显著;大部分种质材料茎叶比在1.0-2.0之间;生产性能较好的种质材料有来自内蒙的圆柱披碱草(NMC32)、北京的麦宾草(BJT37)、青海的披碱草(QHD19)、山西的披碱草(SXD36)、新疆的披碱草(XJD11、XJD5和XJD15)、新疆老芒麦(XJS8)、新疆麦宾草(XJT2)和新疆的肥披碱草(XJE13);牧草产量与鲜干比、种子产量和旗叶长之间显著相关。3.在干旱胁迫下,所分析披碱草属种质材料株高、叶面积、相对含水量和叶绿素含量明显下降,电导率、脯氨酸、SOD和POD含量明显上升。经抗旱隶属度综合分析,来自新疆的老芒麦(XJS17)、内蒙的披碱草(NMD30)、新疆的披碱草(XJD14和XJD11)属弱抗材料,来自内蒙的披碱草(NMD33)和新疆的麦宾草(XJT10)为不抗材料,其余材料抗旱性较强。对抗旱性影响显著的指标有叶片相对含水量、叶面积、相对电导率和叶绿素含量。4.披碱草属不同种质材料叶片解剖结构组成相似,但结构组织量化指标有明显差异。变异系数最大的为中脉厚(38.706%),其次为叶厚(33.843%),变异系数最小的为表皮细胞数(14.134%)。形态解剖结构变异作用较大的指标有:维管束高、维管束宽、叶厚、气孔长宽比、长细胞长、气孔数、上表皮厚、下表皮厚、中脉厚、气孔宽、导管宽、短细胞长及垂周壁形状。5.披碱草属模式种老芒麦光合速率日变化均呈双峰曲线,具有明显的“午休”现象,其他种也有类似现象。老芒麦净光合速率与光合有效辐射PAR和大气CO2浓度Ca显著相关,与空气相对湿度RH和气温Ta相关性不显著。对蒸腾速率影响较大的因子是Ta,其次是Ca。6.醇溶蛋白电泳分析结果表明,供试材料共分离出56条谱带,多态性比例为92.801%,居群间遗传相似系数的变异范围为0.376-0.946,居群内和居群间的多样性所占比例分别为47.67%和52.33%;ISSR分子标记结果表明,利用筛选出的14个引物,共检测出165条谱带,其中具有多态性的谱带为142条,多态性条带比例为87.571%,居群间的遗传分化系数为60.494%,居群内的遗传分化系数为39.57%。这两种结果均表明居群间的变异是该属植物的主要变异来源,并且内蒙和新疆居群遗传多样性较高。同一种类相同地理来源的材料首先聚在一起,但种间也有明显的交叉现象,说明居群间具有比较复杂的关系。总体研究结果表明,披碱草属植物种质材料存在丰富的遗传多样性;披碱草属植物解剖结构具有相似性;无论表型、形态结构、生理生态还是遗传结构与环境因子具有明显相关性;聚类分析表明,披碱草属植物种质材料具有趋同性适应特征;披碱草属植物在形态结构、生理生态特性、农艺性状所表现的适应性是比较一致。这些研究结果为科学地利用和保护披碱草属种质资源提供理论依据。更多还原

【Abstract】 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.更多还原