荒漠区裸果木种群分布与性状适应特征研究

发布时间：2018-05-14 22:43

  本文选题：裸果木 + 生态位模型　； 参考：《内蒙古农业大学》2017年博士论文

【摘要】：裸果木(Gymnocarpos przewalskii Maxim.)为石竹科裸果木属小半灌木,国家一级保护植物。古地中海孑遗植物,对中国西部及中亚荒漠的形成、荒漠植被形成历史的研究具有重要的意义,可开发利用的重要植物资源。裸果木种群分布呈斑块状,分布区生态系统脆弱、极端气候多发及人为因素的干扰等原因,种群数量明显下降。因此探寻气候变化下种群分布特征与性状变异特点及适应性研究显得尤为重要。本文基于生态位模型、解剖学、生态化学计量学及分子遗传学等方法,探讨了裸果木种群适应性及不同生境中性状变异特点。具体研究结果如下:1.基于Maxent模型预测裸果木种群随时间分布区变化及影响的主导因子,得出裸果木在末次间冰期分布面积最大,随着冰期气候的变迁适宜生境面积逐渐缩小。冰期后随着气温的变暖裸果木分布区的面积有所增加,目前主要分布于甘肃河西走廊的大部、新疆部分区域及内蒙古和宁夏两区中西部。而未来气候情景下,适宜生境范围逐渐向甘肃河西走廊地带收缩,分布区面积可能逐渐缩小。因祁连山、阿尔金山、昆仑山及贺兰山山脉的阻挡,冰期在甘肃的河西走廊(疏勒河、党河流域)、玉门关西北缘(哈密)、内蒙古西部(雅布赖)及新疆(塔里木)等盆地形成了部分的避难区;采用刀切法分析得出影响分布面积变化的决定性因子为年降雨量和最冷季节温度。2.对裸果木12个地理种群分布区气候、土壤理化性质、植被特征分析,影响裸果木分布区主要气候因子为年降水量、年均温及年日照时数等。分布区土壤类型为灰漠土、灰棕漠土及棕漠土;土壤养分含量低,氯离子、硫酸根离子及钙离子含量较大,土壤为中性或弱碱性。分布区植物区系成分中古地中海、西亚至中亚种占优势(48%),北温带分布种(24%)和世界分布种(12.8%),温带性属具有绝对优势。以气候特征、土壤因子特征和群落物种组成对样地聚类分析发现,引发裸果木分布区环境异质性的主要原因为降水量等。3.裸果木形态结构具有较强的干旱适应特征。叶片明显肉质,叶肉栅栏组织为环栅型,远轴面和近轴面的结构差异明显;叶肉中央为贮藏组织,细胞形态不规则,体积较大排列松散,部分贮藏细胞内含晶簇;近轴面和远轴面栅栏组织发育程度具有差异;叶脉脉序为基出平行脉,主脉为中心发育两个环形分布的侧脉束,侧脉束内分布贮藏组织,外侧为栅栏组织。不同裸果木种群间形态、叶表皮和结构的22个特征指标进行分析变异系数为0.1 16～0.185、可塑性指数为0.298-0.397,分布于甘肃肃北县及阿克塞县裸果木变异性及可塑性较大,表明种群适应性较强。采用主成分分析和因子聚类法对植株形态、叶表皮特征及叶结构特征分析结果推断,裸果木株高、冠幅、远轴面气孔大小和数目、微管组织及叶片厚度等特征变化较大;相关性分析发现气候因素的降水量及温度导致形态及结构指标间差异较大。4.对不同种群裸果木化学计量学特征分析结果表明,叶C含量变化为319.15～493.98mg·g-1,叶 N 含量变化为 5.41～32.71 mg·-1,叶P含量变化为 0.56～1.36 mg.g-1。种群间化学计量特征存在显著差异,平均值均低于全球陆生植物(1251种)及我国植物(554种)。降水量导致了裸果木高氮、低磷适应特点;裸果木叶N:P为26.09,叶片受易受磷的限制,而P含量易受温度限制;裸果木叶C、N、P与土壤的20～40cm 土层相关性较大,可能养分吸收主要来源该土层。不同种群生态化学计量特征变异为(8.930～15.703),甘肃柳园镇及肃北县的裸果木种群变异较高。5.利用ISSR标记分析裸果木种群遗传多样性结果表明,在群体内标记多态性位点百分率(PPB)为90.01%,Nei's多样性指数(He)为0.2488。居群水平上,PPB变化范围为61.54%～81.12%,平均为67.37%,遗传多样性较高。Nei's基因分化系数(Gst)为0.2790,表明居群间遗传分化较小,居群内存有丰富的遗传变异。UPGMA法及PCA法的分析结果表明,裸果木12个种群可分为4大类群,种群遗传距离与地理距离有相关性;温度、土壤氮含量及全盐含量等环境因素对种群遗传多样性高低有一定影响。
[Abstract]:Bare fruit trees (Gymnocarpos przewalskii Maxim.) are small shrubs of nude carnara, a national first class shrub, and a national first class protected plant. Ancient Mediterranean relict plants, the formation of desert in Western and Central Asia, are of great significance to the study of the history of desert vegetation. It is particularly important to explore the characteristics and adaptability of population distribution and character variation under climate change. This paper is based on the methods of niche model, anatomy, biological chemometrics and molecular genetics. The adaptability of naked fruit tree population and the characteristics of neutral variation in different habitats were studied. The results were as follows: 1. based on the Maxent model, it was found that the largest distribution area of bare fruit trees in the last interglacial period was the largest, and the suitable habitat area was gradually reduced with the change of the glacial climate. As the temperature is warmer, the area of the bare fruit tree distribution area has increased, which is mainly distributed in the large part of the Gansu Hexi Corridor, the part of Xinjiang and the central and western regions of the two regions of Inner Mongolia and Ningxia. In the future climate scenario, the suitable habitat scope is gradually contracted to the west corridor of Gansu and the area of the distribution area may gradually shrink. As the Qilian Mountains, a The barrier of Mount Jinshan, Kunlun Mountains and Helan mountain range, the glacial period in the Hexi Corridor (Shule River, the party river basin) in Gansu, the northwest edge of the Yumen Pass (Hami), the west of Inner Mongolia (iabrei) and Xinjiang (Tarim) and other basins formed part of the refuge area; the decisive factor affecting the change of the distribution area by the knife cutting method is the annual rainfall and the rainfall. The coldest season temperature.2. affects the climate, soil physicochemical properties and vegetation characteristics of 12 geographical populations in bare fruit trees. The main climatic factors affecting the bare fruit are the annual precipitation, the annual temperature and the annual sunshine hours. The soil types are gray desert soil, gray brown desert soil and brown desert soil, and the soil nutrient content is low, chlorine ion and sulfate ion ion are in the distribution area. And the content of calcium ion is larger, the soil is neutral or weak alkaline. The flora of the area is ancient Mediterranean, Western Asia to middle subspecies is dominant (48%), the north temperate zone (24%) and the world distribution species (12.8%), temperate species have absolute superiority. The main reason for the environmental heterogeneity in the bare fruit tree distribution area is the strong drought adaptation characteristics of the.3. naked fruit trees, such as precipitation. The leaves are obviously fleshy, the leaf palisade is the ring gate, the structure of the distal axis and the paraxial surface is distinct. The central leaf of the leaf is a storage organization, the cell morphology is irregular, the volume is large and loose and partial storage is stored. The growth degree of the palisade in the near axis and the distal axis is different; the vein pulse sequence is based on the parallel vein, the main vein is the central development of two circular distribution side veins, the storage tissue in the side veins is distributed, the outside is the palisade tissue. The 22 characteristics of the different naked tree species, the epidermis and the structure of the leaf are analyzed. The coefficient of variation is 0.116 to 0.185, and the plasticity index is 0.298-0.397. The variation and plasticity of bare fruit trees in Subei County and Axi County of Gansu are large, which indicates that the population is more adaptable. The results of the plant morphology, leaf epidermis and leaf structure characteristics of the plant are deduced by the principal component analysis and factor clustering method. The size and number of the pores and the thickness of the microtubules and the thickness of the leaves were changed greatly. The correlation analysis found that the precipitation and temperature of the climatic factors resulted in the difference between the morphological and structural indexes. The analysis of chemometrics of different species of bare fruit trees by.4. showed that the variation of leaf C content was 319.15 to 493.98mg. G-1, and the content of N in leaves changed. The chemical stoichiometric characteristics of the leaves P content changed from 0.56 to 1.36 mg.g-1. were significantly different. The average values were lower than the global terrestrial plants (1251 species) and the Chinese plants (554 species). The precipitation resulted in the high nitrogen and low phosphorus adaptation of bare fruit trees; the N:P of bare fruit leaves was 26.09, the leaves were susceptible to phosphorus, and the P content was easy. Limited by temperature, C, N, P and 20 ~ 40cm soil layers in the soil were related to the soil layer of 20 ~ 40cm, and the nutrient absorption was mainly derived from the soil layer. The variation of the ecological stoichiometric characteristics of different populations was (8.930 to 15.703). The population variation of bare fruit trees in Gansu Liu Yuan town and Subei County was higher than that of ISSR markers in the analysis of the genetic diversity of bare fruit population. The percentage of polymorphic loci (PPB) in the population was 90.01% and the Nei's diversity index (He) was at the level of 0.2488. population, and the range of PPB was 61.54% to 81.12%, with an average of 67.37%, and the genetic diversity of.Nei's gene differentiation coefficient (Gst) was 0.2790, indicating that the genetic differentiation between populations was smaller and the population had a rich genetic variant.UPGM in the population. The results of A and PCA analysis showed that the 12 species of bare fruit trees could be divided into 4 groups, and the genetic distance of the population was related to the geographical distance, and the environmental factors such as temperature, soil nitrogen content and total salt content had a certain influence on the genetic diversity of the population.

【学位授予单位】：内蒙古农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q948
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本文编号：1889829