| 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. |
PDF Full Text Request