【作者】 周龙；

【导师】 廖康；

【作者基本信息】 新疆农业大学 ， 果树学， 2011， 博士

【摘要】 本研究以分布在西天山的新疆特有野生果树资源-野生樱桃李为材料,从群落物种多样性、表型多样性、遗传多样性和濒危物种保育四个方面展开研究,主要研究结果如下：1.大小西沟野生樱桃李分布区的植物资源非常丰富,共有植物98种隶属36科84属。其中乔灌木共有6科15属22种；草本植被共有30科69属76种。大小西沟植物群落中不同生活型乔木层、灌木层和草本层物种丰富度Margalef指数分别为0.95、1.28和5.61,Simpson指数分别为0.7、0.83和0.94, Shannon-Wiener指数分别为1.34、1.93和3.2,三种指数的大小均为草本层>灌木层>乔木层。野生樱桃李分布区植物群落物种多样性的垂直变化研究发现,从海拔1000-1500m的范围内,群落的物种丰富度、均匀度和多样性指数变化趋势基本一致,均表现为先上升后下降的趋势,峰值主要出现在海拔1100-1300m的范围。大小西沟植物群落的优势种主要为野生樱桃李、野山楂、野苹果和野杏,基于群落优势种和重要值划分群落类型为4个主要群落类型,体现了该区植物群落类型特点。2.对8个天然群体20个表型性状的研究结果表明：野生樱桃李不同群体间表型性状差异显著,表型性状变异系数的平均值在群体之间为7.82-19.76%,在群体内部为6.96-40.9%,群体内部的表型差异大于群体间。通过计算20个表型性状的相对极差百分率和表型变异系数发现总体上表型性状变异幅度不大。主成分分析表明果实纵横径、果核重、叶片主脉长度、花冠直径、果柄长度、一年生枝条长度、粗度和果实硬度是引起野生樱桃李群体间性状变异的主要因素。聚类分析研究表明8个野生樱桃李天然群体分为三个大组,聚类结果从地理分布上比较符合实际情况,从生境上也和分布区环境特点吻合。3.确立了野生樱桃李最适SSR-PCR反应的最佳体系为：在20μ1反应体系中,模板DNA浓度为1μl,Mg2+浓度确定1.0 mmol/L,TaqDNA酶用量为LOU,dNTPs的浓度为0.20 mmol/L,引物浓度为0.5μmol/L最佳循环次数为35个循环。用5对引物对50份野生樱桃李种质进行扩增,共扩增出771条带,平均为154.2条。在种群水平上共检测到330条多态性带,每对引物平均可扩增出66条多态性带,多态性带比率为42.8%。7个天然群体所检测的多态位点的丰富程度从大到小的排序依次为：蒙古庙沟>小西沟>一道沟>河漫滩>马金堂沟>庙尔沟>阿培英沟。野生樱桃李遗传多样性的86.05%存在于天然群体内,13.95%存在于天然群体间,表明其遗传变异主要来自于天然群体内部,少部分来自于天然群体间。通过计算遗传距离和遗传相似度系数发现天然群体一道沟和河漫滩的遗传相似性水平最高,天然群体小西沟和马金堂沟的遗传距离最大,遗传分化程度高。以平均遗传距离0.028为阈值7个天然群体被聚为四大类,SSR聚类结果基本和表型聚类一致。4.对野生樱桃李种质资源濒危原因分析发现是多种因素相互作用的结果,既有本身繁育系统上的限制,又与外界环境的恶化相关,是各种生物学特征之间以及生物学特征与环境之间不协调作用的迭加效果。在加强就地保护、迁地保护策略的同时应该加强法制建设和科研力度,建立离体保存基因库,注重在保护中的合理开发和利用,使保护和利用紧密结合。更多还原

【Abstract】 In this study Prunus divaricata Ldb.endemic wild fruit tree of Xinjiang were studied at four leves such as community species diversity, henotypic diversity, genetic diversity and endangered species conservation. The main research results were as follows.1. The Prunus divaricata distribution area in Da xiao xi gou is abundant in plant resource, the total plant 98 species belongs to 36 families 84 generaand. There were 22 species of tree and shrub plants belonging to 15 generaand 6 families and 76 species of herb plants belonging to 69 generaand 30 families. Study on different life forms such as tree layer, shrub layer and herb layer in Da xiao xi gou plant community we found the Margalef index is 0.95,1.28 and 5.61, the Simpson index is 0.7,0.83 and 0.94, Shannon-Winner index is 1.34,1.93 and 3.2,three different index show that the species richness order was that the herb layer> shrub layer>tree layer. The vertical variation of species diversity in Prunus divaricata distribution area is concentrate on the range of 1000-1500 meter. The species diversity, evenness and diversity index variation trends are similar. They all shows a trend of rise first then fall and the peak value occurred in 1000-1300 meter. The dominant species of Daxiaoxigou plant community is mainly includes Prunus divaricata, wild hawthorn, wild apple and wild apricot. The plant community was divided into 4 main community types based on the dominant species and the importance value. The result embodied community types character of this area.2. Based on 8 natural populations and 20 phenotypic traits we found that difference was significant between different natural populations. The mean of coefficient variation between different natural populations is 7.82-19.76, the mean of coefficient variation in different natural populations is 6.96-40.9%, phenotypic difference in different natural populations is higher than the value between different natural.Comparison with percentage of relative range and phenotypic coefficient variation we found that the variation range is not change much. The principal component analysis shows that the phenotypic index such as fruit length, fruit width, nutlet weight, leaf length, corolla diameter, fruit stalk, shoot length, shoot diameter, fruit hardness are main factors which provoked character variation between different natural populations. Cluster analysis research shows that Prunus divaricata 8 natural populations divided into 3 main group. The cluster result agreed with the actual situation of geographical distribution, it is also match with the environmental features and the habitat of distribution area. 3. SSR-PCR reaction system of Prunus divaricata is established. That optimistic RCR system of 20μL which contained 0.2mmol/L dNTP, 1.0mmol/L Prime, 1.0mmol/L Mg2+,1.0 U Taq DNA polymerase, 1μl template DNA and 35 times cycle. SSR was adopted to study 50 germplasm materials of Prunus divaricata,771 bands were detected with 5 pairs of primers and 330 of them were polymorphic, the mean proportion of polymorphism was 154.2, which amounted to 42.8%. Among 7 natural populations polymorphic loci detection, the rich degree order sorting is Menggumiaogou>Xiaoxigou>Yidaogou>Hemantan>Majintanggou> Miaoergou>Apeiyinggou. The genetic variation being 86.05% within the Prunus divaricata natural populations and 13.95% among the natural populations. The genetic similarity and genetic distance showed that Yidaogou and Hemantan natural populations had the nearest relationship and the Nei genetic distance was the largest in the Xiaoxigou and Majintanggou natural populations.They had higher genetic differentiation degree.7 natural populations was divided into 4 main group based on the average genetic distance(0.78) clustering. The results are consistent with the SSR clustering and the phenotypic clustering.4. Endangered mechanism of Prunus divaricata germplasm resources analysis revealed that the results caused by interaction of various factors, and its related with the breeding system restriction and the environmental deterioration. The incoordination was caused by superimposed effect which from biological characteristics and between the biological characteristics and the external environment We should strengthened kynamics on site protection, relocation protection, legal system construction and scientific research, at the same time in vitro conservation gene bank should be established. We should also pay attention to development and utilization reasonable and make it closely combined with protection and utilization on wild Prunus divaricata germplasm resources.更多还原