【作者】 田尚衣；

【导师】 杨允菲；

【作者基本信息】 东北师范大学 ， 生态学， 2011， 博士

【摘要】 在松嫩草地植被组成成员中,多年生根茎型禾草是一类最重要和最基本的生活型成员,是草原群落层片的建造者,也是维持草地生态系统平衡的限制者。根茎禾草在松嫩草地植被中的重要地位主要取决于根茎禾草的无性繁殖特性及营养贮藏能力。根茎禾草的地下器官可宿存于土壤多年,是联接植物与土壤的重要环节,是植物与土壤相互作用的界面。根茎的无性繁殖特性及营养贮藏能力不仅与环境条件、季节变化和宿存土壤的年限有关,更重要的是与根茎内部非结构性碳水化合物组成的分配格局、生物化学代谢途径及生理调节过程密切相关。因此,多年生根茎禾草非结构性碳水化合物的生物化学代谢机制与其营养繁殖特性的关系是生理生态学研究的重要内容。芦苇(Phragmites communis)是松嫩草地植被中优势禾草之一,是典型的无性系植物,其地下器官具有较强的无性繁殖特征及营养贮藏功能。本论文以芦苇种群根茎构件为研究对象,初步研究了芦苇根茎中果聚糖的组成及理化性质;建立了检测果聚糖组成、含量及分子量的定性、定量分析方法体系,论证了该方法体系对芦苇根茎样品的适应性;在此基础上研究了芦苇种群不同龄级根茎及每一龄级根茎中不同繁殖体构件中果聚糖的分布格局、生物化学代谢途径及生理调节作用。本研究基于生物化学和生态学两个视角,从芦苇种群不同龄级根茎构件的生态特征及适应过程为切入点,分析芦苇根茎内果聚糖生物化学代谢途径及对芦苇种群无性繁殖及营养贮藏的调控作用,籍以揭示芦苇种群不同龄级根茎的繁殖对策及种群更新机制。通过调查分析及研究获得如下结果:1芦苇根茎中非结构性碳水化合物的组成和理化性质的研究结果表明:采用生物化学制备方法,对芦苇根茎样品经提取、纯化后获得一白色粉末状的多糖PAWDG,将其水解经HPLC分析获得单糖组成为果糖和葡萄糖,其摩尔比为8.7,证明该多糖是果聚糖,其聚合度为大于8以上的多聚果糖;通过薄层色谱分析认证该多糖是直线型果聚糖且其平均总量为23.56%。由此证明松嫩草地芦苇种群根茎中果聚糖为非结构性碳水化合物的主要贮藏类型。2根据色谱学、光谱学的原理建立了芦苇根茎样品中检测果聚糖组成、含量和分子量等分析方法体系,获得了如下三种分析方法:⑴建立并论证了《芦苇根茎禾草总果聚糖高通量分析方法》;⑵建立并论证了《芦苇根茎果聚糖及其代谢物的同时分离及定量分析方法》;⑶建立并论证了《芦苇根茎果聚糖分子量及分子量分布检测分析方法》;3芦苇种群根茎样品中果聚糖组成的定性分析结果如下:芦苇根茎样品中可定性检测到多聚果糖、蔗果四糖、蔗果三糖、蔗糖、葡萄糖和果糖等6种糖组分;4芦苇种群根茎样品中果聚糖组成的定量分析结果如下:在方法限定的检测限及灵敏度下可定量检测到多聚果糖、蔗果三糖、蔗糖、葡萄糖和果糖5种糖组分。5通过对芦苇根茎构件的数量特征调查发现,芦苇种群的营养繁殖及种群更新等无性系特证是通过不同龄级根茎构件功能的精确分工实现的。其中,芦苇种群不同龄级根茎上根茎节的数量特征为二次多项式分布,其中三龄级根茎上其根茎节的数量分布最多。同时,萌发芽和休眠芽繁殖体构件在二、三和四龄根茎上的数量分布最多。由此表明,这三个龄级根茎主要承担着即要扩展生态位空间又要进行营养繁殖的双重功效。6不同龄级根茎对利用型组合糖及贮藏型组合糖的分配格局说明一龄根茎对环境的影响较为敏感,各种糖的分配响应变异较大,种群意义上通过生理调节可塑性对一龄根茎进行调节和保护;二龄和三龄根茎生物化学代谢周期长,生理调节活跃,对呼吸消耗底物的利用有稳定的生物化学代谢调控补偿机制,形态生长快速,种群意义上通过扩张领域,繁殖后代等重要作用在芦苇种群根茎年龄结构中表现出绝对优势的社会生态位;四龄和五龄根茎生物化学代谢周期相对较短,但生理贮藏周期相对较长,贮藏物质积累丰富,种群意义上承担着后勤保障,补给供养的作用,一旦芦苇根茎年龄结构中社会生态位出现断层,它们所具备的生物代谢活性能够进行营养繁殖,及时以补充种群数量进行更新,故四龄、五龄根茎是芦苇种群稳定发展的基础。7通过研究不同繁殖体根茎构件中生物代谢调控过程与季节变化的关系,从生物化学和生态学两个视角透视了不同繁殖体根茎构件功能对芦苇种群根茎系统总体生态效应的协调作用。研究证实,芦苇种群营养繁殖构件自身贮藏物质的生物化学代谢过程与季节变化密切相关,不同的变化时期有不同的代谢途径和不同组成糖的利用方式,由此传递的化学信息暗示芦苇种群无性繁殖的总体功能是由不同繁殖体根茎构件协同作用实现的。首先,环境变化促使根茎构件内部代谢途径的改变,然后在生理上通过对糖的不同利用方式实现芦苇根茎系统的整体繁殖特征及由此产生的生态效应,在整个过程中不同繁殖体根茎构件依次发挥自身的调节作用,以实现构件功能与整体功能的一致性。综上所述,芦苇根茎构件中果聚糖的分布格局不仅依赖于季节变化,而且还与芦苇根茎的年龄及每一龄级根茎上不同繁殖体根茎构件有关。果聚糖组成对芦苇根茎构件种群的生理调控作用及代谢机制蕴含着芦苇种群特有的繁殖对策及更新机制。更多还原

【Abstract】 Perennial rhizomatic grasses are the most basic and important life forms which make up the grassland vegetation in Songnen grassland, and they also construct the community synusia of grassland and limit the balance of grassland ecosystems. The important positions of rhizomatic grasses mainly depend on its asexual reproduction and strong function of storage in Songnen grassland. Because the perennial rhizomes grasses live in the soil for many years, and they are the important parts of connection with plants and soil, and they are also the interface between plant and environment, especially the interaction among soil systems. The reproductive and storage capacity of rhizomes not only correlate with environmental conditions, seasonal changes and the living years in soil, but also closely related with composition, distribution and physiological metabolic processes of the non-structural carbohydrate which the rhizomes store. The physiological changes by metabolic processes of plants depend on the pressure to survive, and always adapt to the habitat conditions. Therefore, study on the relationships between metabolic mechanism of non-structural carbohydrate and their vegetative propagation characteristics in the perennial rhizomatic grasses is one of the most important contents of physiological ecology.Reed (Phragmites communis) is one of the dominant and representative rhizomatic grasses in Songnen grassland; the underground organs of reed have stronger ability of asexual reproduction and nutrient storage. In this study, reed population which has integrated physiological connection was the research object, a preliminary study was consulted on the physical and chemical properties of carbohydrate of the reed rhizomes; established to detect the components of non-structural carbohydrate and the level of qualitative and quantitative analysis system, and demonstrated the methodology of the adaptation to reed rhizome samples; on the basis of this, non-structural carbohydrate of reed age-specific rhizome and each age rhizomes were studied, viz, metabolism biochemistry, physiology and spatial distribution patterns of fructans in reed population. This study is based on biochemistry and ecology, started with ecological characteristics and adaptation process of reed population at different aged rhizomes, researched the physiological role of components of fructans effecting on composition of different aged rhizomes, analyzed the biochemical mechanisms of fructans, hoping to show the reproductive strategies and regenerative mechanism of reed population at different age levels.1 The physical and chemical properties and components of non-structural carbohydrate in the reed rhizomes showed as fallows:Biochemical methods was used by the extraction and purification to obtain the white powder which was a polysaccharide (PAWDG), then got its hydrolysis and obtain the fructose and glucose, the molar ratio is 8.7 which was certificated to fructans and it’s a polymer of fructose whose degree of polymerization is more than 8; and it was certificated to liner type fructosan by TLC analysis; the averaged total fructans make up 23.56% of the reed rhizome. It provided that the fructans was a main stored type of non-structural carbohydrate of reed population.2 Established the method systems for detecting the components, contents, and molecular weight of fructans in reed rhizomes according to chromatography and spectroscopy, accessing to three analysis methods as follows:(1) Established and demonstrated "the high-throughput analysis methods of total fructan in reed rhizomes";(2) Established and demonstrated "the simultaneous separation and quantitative analysis methods of fructan and metabolites in reed rhizomes";(3) Established and demonstrated the "the molecular weight and molecular weight distribution methods of fructan in reed rhizomes ".3 The qualitative analysis of components of fructans in reed rhizomatic samples as follows: there are six kinds of carbohydrates in the reed rhizome by qualitative analysis which are poly-fructose, Kestotetraose, 1-kestose, sucrose, glucose and fructose4 The quantitative analysis of components of fructans in reed rhizomatic samples as follows: the quantitative analysis methods could detect the poly-fructose, 1-kestose, sucrose, glucose, and fructose by limited detection degree and sensitivity in reed rhizomes.5 According to survey quantity characteristics, asexual features of reed population such as vegetative reproduction and regeneration were achieved by precise division through different age rhizomes. In general, the quantitative character of different age rhizomes of reed population showed obvious normal distribution and a large number of probability distribution at 2-4 ages. At the same time, the quantitative character of break and dormant buds of reed rhizomes also showed normal distribution at 2-4 ages. Thus, the reed rhizomes at these three ages undertook the dual efficacy of both expanding niche space and vegetative reproduction.6 The distribution pattern of utilized and storage type of combined carbohydrates showed that 1 age rhizome was sensitive to environments, the response variation of all kinds of carbohydrates was big, and increased the physical adjustment plasticity to input and protect the 1 age rhizome; the 2 and 3 age rhizomes had the long biochemistry metabolic cycle, actively physiological regulatory, stable biochemistry regulatory mechanism to use the metabolic consumption substrate, and fast growth of morphology. It showed the absolute advantage of social niche of reed rhizomes though the important function such as expanding space and reproduction at population level; the 4 and 5 age rhizomes had a shorter biochemistry metabolic cycle, but a longer physiological storage cycle and rich storage materials accumulations. It undertook the logistics and supply nutrition at population level. If there is a faulting in the social niche of reed age rhizomes, their biological metabolic activity could do vegetative propagation for supplemental population regeneration timely. Thus, 4 and 5 age rhizomes were the base rhizomes for reed population developing stably.7 The different traits of rhizome modules coordinated effecting on reed population rhizomes system was observed at biological chemistry and ecology perspectives though studying the relationship between biological metabolic regulation process of the different traits of rhizomes and seasonal changing. The results show that there was a closely relationship between biochemistry metabolic process of storage materials of reed population vegetative propagation and seasonal changing, and there was different metabolic pathways and ways of using carbohydrates with seasonal changing, so the way of transferring chemical message implied that the total special function of reed population was achieved by synergy of different traits of rhizome modules. Firstly, the internal metabolic pathways of the rhizome modules were changed by environmental changing, then the total ecological effect of reed rhizome system was achieved by different ways of using carbohydrates on the physiology. The different traits of rhizome modules played adjustment effect in the whole process, in order to achieve the consistency of the module function and whole function.In a word, the spatial distribution patterns of fructans of reed rhizomes not only depended on seasonal changing, but also related with the age of reed rhizomes and the propagule traits. The components of fructans effecting on physiological regulation and metabolic mechanisms of reed module rhizome population implied the special reproductive strategies and regenerative mechanism of reed population.更多还原