刈割干扰与盐碱胁迫对不同密度羊草无性系空间拓展的影响

发布时间：2018-06-29 19:00

本文选题：刈割干扰 + 盐碱胁迫　；参考：《东北师范大学》2017年硕士论文

【摘要】：近年来,土地盐碱化程度日益加重引起广泛的关注。据了解,松嫩平原是世界三大盐碱土分布区之一,其中吉林省西部就是松嫩平原土地盐碱化十分严重的地区。羊草作为该地区优势种,也是一种耐盐碱的根茎型克隆植物,其强大的营养繁殖能力使其在占据空间资源上拥有巨大优势。但历史原因加上盲目垦荒、过度放牧等人为因素干扰,使羊草草地逐渐退化,出现大面积由耐盐碱植物(虎尾草、碱蒿)形成的碱斑,且盐生植物群落在逐年扩大,羊草斑块逐渐走向破碎化。研究和揭示羊草向盐碱斑块的空间拓展策略,对于深入理解和认识盐碱化草地的恢复过程及机制具有重要科学意义。基于Grime植物生境选择对策理论(C-S-R三角),干扰、胁迫以及竞争是影响克隆植物空间拓展的主要外在驱动力。由此,本研究采用盆栽控制法,模拟野外羊草从羊草草地向盐碱草地空间拓展的全过程,全面地揭示了刈割干扰(无刈割、刈割)、密度制约(高、低密度)以及盐碱胁迫(高、低盐碱)三因素对羊草无性系种群空间拓展潜力(地下拓展根条数、平均根长、平均间隔子长)、拓展后的繁殖力(单株平均分蘖数、平均分蘖率、地下根茎芽数)以及定植能力(分株数×地上平均拓展距离)的作用及交互效应。获得如下主要结论:(1)无论是否面临密度制约、刈割干扰以及盐碱胁迫,羊草无性系都表现出明显地主动向新斑块(盐碱斑块)扩繁的空间拓展行为。(2)刈割干扰对羊草空间拓展潜力的影响主要表现在:刈割显著降低羊草向盐碱胁迫区拓展的根条数,刈割干扰对间隔子长度的影响依赖于盐碱胁迫条件和密度制约的初始背景,在高盐碱-高密度条件下,刈割干扰显著增加间隔子长度;刈割干扰对拓展后植株繁殖力的影响主要表现在根茎芽数,即刈割干扰降低根茎芽数;刈割干扰对羊草拓展后的定植能力没有显著影响,但显著提高了平均空间拓展距离。(3)盐碱胁迫强度对羊草空间拓展潜力的影响仅表现在间隔子长度,且依赖于密度制约的初始背景和刈割干扰:在低初始密度-刈割干扰和高初始密度-无刈割干扰条件下,低的盐碱胁迫显著增加间隔子长度;而在高初始密度-刈割干扰条件下,高盐碱胁迫增加间隔子长度。而盐碱胁迫对拓展后的繁殖力以及定植能力均没有显著影响,但盐碱胁迫显著影响了分株数,且依赖密度制约的初始背景。(4)密度制约对羊草空间拓展潜力的影响也仅表现在间隔子长度,且依赖盐碱胁迫条件和刈割干扰:仅在低盐碱胁迫-刈割干扰条件下,低的密度制约会增加间隔子长度;密度制约对拓展后的繁殖力和定植能力均具有显著影响,表现为:低初始密度条件下拓展的植株具有显著高的分蘖率以及定植能力。综上,刈割干扰、密度制约以及盐碱胁迫对羊草无性系空间拓展潜力、繁殖力以及定植能力均具有不同强度的作用效应。总体分析,刈割干扰是影响羊草无性系空间拓展的最重要因素,而盐碱胁迫则是羊草无性系空间拓展的最弱影响因素,但是目前我们还不能确定盐碱胁迫的弱效应是否由于实验处理中的胁迫强度较低所致。具体分析,刈割干扰会刺激植物增加空间拓展距离,而代价是降低对潜在繁殖种群等地下构件生长的投入;降低密度制约不会影响克隆植物在空间上的主动拓展行为,但低的密度制约会增强克隆植物的繁殖能力和定植存活能力,从而提高其向新斑块的拓展能力;而盐碱胁迫常常与密度制约和刈割干扰共同耦合在一起调控克隆植物的空间拓展潜力,低密度、低盐碱胁迫以及刈割生境组合下无性系空间拓展潜力最强。
[Abstract]:In recent years, the degree of soil salinization has become more and more serious. It is understood that the Songnen Plain is one of the three largest saline alkali soil distribution areas in the world. In the western Jilin Province, the land salinization in the Songnen Plain is very serious. As the dominant species in the region, Leymus chinensis is also a salt tolerant rhizomatous clone plant with strong nutrition. The reproductive capacity has a great advantage in the occupying space resources. But the historical reasons add to the blind reclamation, overgrazing and other factors to interfere with the factors that cause the grass grassland to gradually degenerate, and the alkali spots formed by the salt tolerant plant (tiger tail grass, Artemisia Artemisia) appear in large area, and the halophyte community is expanding year by year, and the patch of Leymus chinensis is gradually broken to fragmentation. Exploring and revealing the spatial expansion strategy of Leymus chinensis to saline alkali patches is of great scientific significance for understanding and understanding the recovery process and mechanism of saline alkali grassland. Based on the theory of Grime plant habitat selection strategy (C-S-R triangle), interference, stress and competition are the main external driving forces affecting the space expansion of clonal plants. A potted plant control method was used to simulate the whole process of field expansion of Leymus chinensis from Leymus chinensis grassland to saline alkali grassland, and the spatial expansion potential of three factors, including cutting interference (no cutting, cutting), density restriction (high, low density) and salt alkali stress (high, low salt), was revealed. The effects and interaction effects of expanded fecundity (average number of tillers per plant, average tillering rate, number of subsurface rhizome buds) and colonization capacity (number of plant number by average expansion distance) and interaction effects were obtained. The following main conclusions were obtained as follows: (1) the clones of Leymus chinensis were obvious whether or not they were faced with density, cutting and salt stress (2) the effect of mowing interference on the space expansion potential of Leymus chinensis is mainly manifested in: mowing significantly reduces the number of root strips extending from Leymus chinensis to saline alkali stress area. The effect of mowing interference on the length of the spacer depends on the initial background of salt stress and density constraints, and in high salinity Under the condition of alkali high density, the cutting interference significantly increased the length of the spacer, and the effect of mowing interference on the growth of the plant was mainly in the number of rhizome buds, that is, the cutting interference reduced the number of rhizome buds; the cutting interference had no significant influence on the planting ability after the expansion of Leymus chinensis, but increased the average space expansion distance. (3) strong saline alkali stress. The effect on the spatial expansion potential of Leymus chinensis is only in the interval length, and depends on the initial background of density restriction and the cutting interference: low salinity stress increases the length of the spacer significantly under the low initial density mowing interference and high initial density without cutting interference, while high salinity under the high initial density mowing interference condition. But salt alkali stress had no significant influence on the expanded fecundity and colonization ability, but salt stress significantly affected the number of plants and the initial background of density restriction. (4) the effect of density restriction on the space expansion potential of Leymus chinensis was also only in the interval length, and it depended on the condition of salt stress and mowing. Interference: under low salt stress - cutting interference conditions, low density constraints will increase the length of the spacer; density constraints have a significant impact on the expansion of the colonization and colonization ability, showing a significant higher tiller rate and colonization ability under the low initial density. And salt and alkali stress have different effects on the spatial expansion potential, fecundity and planting ability of Leymus chinensis clones. Overall analysis, mowing interference is the most important factor affecting the space expansion of Leymus chinensis clones, while saline alkali stress is the weakest factor in the space expansion of Leymus chinensis clones, but we are not yet determined at present. The weak effect of saline alkali stress is due to the low stress intensity in the experimental treatment. The specific analysis shows that the cutting interference stimulates the plant to increase the space expansion distance, while the cost is to reduce the input to the growth of subterranean components, such as the potential reproductive population, and the reduction of density will not affect the active expansion behavior of the croon in space, but low Density constraints can enhance the reproductive and colonization viability of cloned plants, thus improving their ability to expand to new patches, while salt stress is often coupled with density constraints and mowing interference to regulate the spatial expansion potential of clonal plants, low density, low salt stress, and the spatial expansion of clones under combination of mowing habitats. The potential is the strongest.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S543.9

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