【作者】 侯钰荣；

【导师】 安沙舟；

【作者基本信息】 新疆农业大学 ， 草业科学， 2010， 博士

【摘要】 伊犁绢蒿(Seriphidum transiliense)属于菊科绢蒿属半灌木,在新疆集中分布于北疆地区的平原与低山,是当地春秋放牧场主要的牧草之一。由于生态环境脆弱、自然条件差,再加上缺乏管理、过度放牧等人为因素,致使该类草地退化严重;同时,导致区域生态环境恶化,植被覆盖度减小,土地裸露面积增大,草-土-畜失衡,严重制约着新疆畜牧业的稳定发展。本研究通过小尺度范围内人工设定不同刈割强度试验,采取年内多次采样方法,研究了伊犁绢蒿生理适应、构件变化和叶功能性状的动态变化及形成规律;同时,在大尺度范围内经验性地选择有代表性的典型样地,采用秋季一次性采样方法,探讨自然状态下,伊犁绢蒿构件、土壤化学性质和分子水平对生境和地形的生态适应;通过生理适应和生态适应两方面内容,试图揭示伊犁绢蒿的生理生态可塑性和趋异适应机理,为草地实际生产利用提供科学依据。主要研究结论如下:(1)伊犁绢蒿对刈割强度的生理适应对策随着时间的推移,叶片在叶绿素、贮存性营养物质中基本表现为先升高→再降低→再升高的趋势;而贮存性营养物质的茎和根系有相同的变化规律,均呈现升高→降低→升高→降低的趋势,根系中的淀粉含量则相反;渗透调节物质含量在叶片、茎和根系中的变化规律相同,均呈现降低→升高→降低→升高的趋势;随着刈割强度的变化,均以C2占有绝对优势,C0处于劣势,说明C2对刈割有更强的生态适应性;2008年各指标含量低于2009年,主要原因是2009年降水量多于2008年,植株的生理适应性增强。(2)伊犁绢蒿构件对刈割强度的适应对策随着刈割强度的增加,C2能促进植株构件更适应刈割强度的生态适应,说明适度刈割可以刺激植株的良性生长;C0的适应性最终趋于矮化、小型化和匍匐化。通过降低植株高度、减少分枝数、停止有性繁殖,增大地下部分根系干重等措施来适应刈割胁迫和维持生命;刈割时间对植株影响程度不同,秋季刈割给植株带来的构件胁迫远大于春季刈割。(3)伊犁绢蒿叶功能性状对刈割强度的生态适应对策与LDMC和单个叶片相对含水量相比,SLA对刈割强度的敏感性更强一些;对伊犁绢蒿的影响程度春季刈割明显大于秋季刈割,且在各刈割处理中,C5略占优势,更能适应刈割胁迫;C0仍排名最末,对刈割胁迫的生态适应性最差。(4)伊犁绢蒿构件对生境和地形的生态适应对策从不同生境来讲,伊犁绢蒿长势的优劣基本可以确定为生长于察布查尔县的居首,新源县、沙湾县和乌鲁木齐市的居中,奇台县的最末;5个生境中,奇台县植株个体差异最小,均匀性最好,生态适应性比较均匀。茎干重对地上生物量、主根干重对地下生物量贡献率均最大,他们之间均有显著正相关关系和相同的拟合函数,且存在相同的物质生产和积累规律。从不同地形来讲,平地和阳坡的伊犁绢蒿比丘陵或阴坡的具有更强的生态适应性,不同地形间构件系对地上与地下生物量的贡献率和拟合函数关系与不同生境所得结论相似。(5)伊犁绢蒿土壤化学性质对生境和地形的适应对策生境和地形均对土壤化学性质有一定影响,而且各指标间也存在互动或阻碍作用,但有机质、碱解氮、速效钾和有效磷在土壤剖面结构上有一致的变化趋势,均表现为0-10cm>10-20cm>20-30cm,土壤pH值表现为0-10cm<10-20cm<20-30cm,土壤总盐表现为10-20cm>20-30cm>0-10cm;总盐和pH值与其他养分呈负相关关系;土壤有机质、碱解氮、速效钾和有效磷均以平地>阳坡>阴坡>丘陵为主,地形对土壤pH值的影响没有一定的规律性,土壤总盐基本呈阴坡>阳坡>平地,规律性较强。(6)伊犁绢蒿遗传多样性对生境和地形的生态适应对策伊犁绢蒿多态位点百分率为78.4%,同一引物组合在不同群体扩增的多态性带数基本相同。通过居群内聚类分析表明,根据地形的水热状况对植株的影响将平地和阳坡聚为一类,将阴坡聚为一类;居群间没有明显的分界点,说明地形对伊犁绢蒿遗传多样性的影响大于生境带来的影响。更多还原

【Abstract】 Seriphidium transiliense belongs to Compositae Seriphidium plant that it concentrated distributed in the flatland and low mountain region of north, which is the main forage of spring-autumn pasture in Xinjiang. Because the ecological environment is fragile, nature condition is poor, in addition, the management is shortage, overgrazing, people’s factors and so on. All the reasons caused the type grassland serious degradation, at the same time, it also leaded regional ecological environment deterioration, the coverage of vegetation decreased, the area of bare land was increased, grass- soil-livestock imbalanced, which seriously restricted the stable development of livestock husbandry. The experiment based on the manual setting of different mowing intensities in a small sacle range, the method of sampling was taken multiple times in a year, and we studyed the dynamic change and their formation law for physiological resistance, variation of modules composition, leaf founction characters resistance of S. transiliense. Simultaneously, we experimentially chosed the representatively typical plots in large scale range, explored the influence for modules and molecular level of S. transiliense in different habitats and different terrains under nature condition. Sampling only once in autumn,we researched the response for habitats and terrains in modules, soil and genetic diversity. In order to comprehensively revealed the ecological plasticity and disvergence adaptation mechanism, and provided scientific basis for grassland practical productical use. The main results were as follows:(1)The ecological adaptation regularity of mowing intensity for S. transiliense’s physiological resistance Chlorophyll and storage nutrition substances, leaf exhibited a law as increased→decreased→increased; Stem and root had a same change law, they all presented increased→decreased→increased→decreased; Starch’s root was contrary. Osmosis regulating substances had a identical law in leaf, stem and root, they all presented increased→decreased→increased→decreased; With the change of mowing intensity, C2 possesed the absolute advantage, C0 was at disadvantage. The content of nutrition substance was lower in 2008 than 2009, the main reason was the precipitation less in 2008 than in 2009, the plant had a stronger ecological adaptation.(2)The ecological adaptation regularity of mowing intensity for S. transiliense’s modules With the mowing intensity increased, C2 could promote modules of plant individual in a advantage position with mowing intensity increased, it showed that proper mowing could stimulate plant toward benign direction growth; Plant individual of C0 tended to dwarf, miniaturization and creeping finally, usually, C0 could lowered plant height, reduced branch numbers, and stopped sexual reproduction, underground, plant individual could increase root dry weight or other measures to adapt mowing stress and maintain life; Mowing time had a large influence for plant, mowing in autumn stressed for plant more serious than mowing in spring.(3)The ecological adaptation regularity of mowing intensity for S. transiliense’s leaf function charactersCompared with LDMC and single leaf relative water content, SLA had more sensitive for mowing intensity than other indexes; Mowing in spring was more obvious influence than mowing in autumn, C5 appreciably possessed advantage, C0 was also ranking in the end, it had the worst ecological adaptation for mowing intensity.(4)The ecological adaptation for habitats and terrains of S. transiliense’s modulesThere could be determined that growth condition of Chabuchaer country was the first in different habitats, Xinyuan country, Shawan country and Urumqi city were in the middle, and Qitai country was the last one. Plant individual difference was the smallest and uniformity was the best of Qitai country in the five habitats. The contribution rate of stem dry weight for aboveground biomass and main root dry weight for underground biomass all were the largest, and there even was a strong positive correlation and had a similar fitting function between them, and also had same material production and accumulation trend. In different terrains, the S. transiliense in flatland and sunny slope had a stronger ecology adaptation than in shady slope or hilly. The contribution rate and fitting function of aboveground and underground biomass in different habitats and different terrains got a similar conclusion.(5)The ecological adaptation for habitats and terrains of S. transiliense’s soil chemical propertiesHabitats and terrains had a influence for soil chemical properties and there was existing interaction or hindrance effect in every index, but organtic matter、available nitrogen、available kalium and available phosphorus had a consistent change trend on soil profile structure, which were 0-10cm>10-20cm>20-30cm, soil pH was 0-10cm<10-20cm<20-30cm, and soil total salt was 10-20cm>20-30cm>0-10cm. Soil total salt and pH had a negative correlation with other soil nutrients. The main form in soil organtic matter, available nitrogen, available kalium and available phosphorus all were flatland>sunny slope>shady slope>hilly. There was no explicited law in terrains for soil pH, soil total salt presented a strong law that was shady slope>sunny slope>flatland.(6)The ecological adaptation for habitats and terrains of S. transiliense’s genetic diversityPercentage of polymorphism loci of S. transiliense was 78.4%, polymorphism band numbers were probably at the same level in different population amplification on the same primer combination. In one population, it presented that plant individual could divide two types according to water and heat, which the first type was flatland and sunny slope, the other type was shady slope; In five populations, it could be divided two types, the first one contained Chabuchaer country and Qitai country, the other one contained Urumqi city, Shawan country and Xinyuan country, and terrains effect was large than habitabs for genetic diversity of S. transiliense.更多还原