本土和入侵生态型乌桕对全球变化主要因子的响应研究

发布时间：2018-02-25 22:25

本文关键词： 生物入侵全球变化臭氧二氧化碳紫外辐射氮沉降　出处：《南京农业大学》2016年博士论文　论文类型：学位论文

【摘要】：植物入侵作为全球变化的一个重要组成部分,与其他全球变化因子关系密切,相互作用,密不可分。探究入侵植物对全球变化因子的响应,对深入了解入侵植物的生理生态学变化,监控外来植物入侵具有重要意义。二氧化碳浓度(C02)及臭氧(O_3)浓度升高、紫外(UV-B)辐射强度增强和氮沉降均是当前全球变化的重要表现。这些外在环境因素的变化无论是对植物个体的生长与繁殖,还是对群落结构变化以及生态系统的演替都会产生直接或间接的影响。另外,环境变化因子之间也常常相互影响,因而两个及以上的环境因子的变化对植物的影响可能会发生一种非加和效应。然而到目前为止,对于这四种环境变化因子之间的相互作用对植物的影响仍不明晰,特别是针对入侵植物的研究尤为少见。入侵植物之所以能够成功入侵新地域,其原因一方面可能是由于入侵植物本身就具有比本土物种强的竞争力,另一方面可能是因为入侵植物被引入新生境后受外界环境因素的影响而发生了适应性进化进而提高了竞争力。因此,入侵物种与其入侵地的伴生物种,或入侵物种的入侵生态型与本土生态型对外界环境因素变化的响应也可能存在明显差异。本文主要围绕O_3与其他环境因子(CO_2、UV-B和氮沉降)的相互作用,以乌桕作为主要供试材料,采用室内控制环境箱的方法,探究入侵物种乌桕与3种本土伴生物种,以及入侵与本土生态型乌桕对03和CO_2浓度升高的响应。采用室外开顶式同化箱的方法,探究03浓度升高和UV-B辐射增强,以及03浓度升高和不同方式的氮沉降模拟对入侵和本土生态型乌桕生长表现的影响。主要研究结果如下:1.通过入侵植物乌桕与本土 3种伴生物种的生长表现对比,发现入侵种乌桕具有明显的生长优势,且具有较低的浓缩单宁含量。通过入侵和本土生态型乌桕单一种植以及两者混合种植进行生长表现对比,发现入侵生态型乌桕在生物量、株高等生长指标方面优于本土生态型乌桕,特别是在混合种植时,入侵生态型性乌桕相比本土生态型乌桕的竞争优势更为明显。结果说明乌桕在被引入新生境后,发生了适应性进化,其资源分配机制也发生了调整,即原先用于生产高消耗次级代谢产物的资源一部分被转化为用于低消耗的植株生长,使得不但入侵物种乌桕相对于本土伴生物种具有很强的竞争力,而且入侵生态型乌桕相对本土生态型乌桕也具有竞争优势。结果验证了竞争力进化增强假说。2.入侵生态型乌桕相对于本土生态型乌桕对UV-B辐射强度升高的响应更为敏感,另外,UV-B辐射增强时,两生态型在叶凋落物量上存在明显相反的变化,即本土生态型乌桕的叶凋落物量明显上升,而入侵生态型乌桕的叶凋落物量明显下降,这样可能会改变土壤养分循环过程,进一步影响外来植物的入侵表现。由此得出,入侵生态型乌桕先前为了成功入侵新生境,可能改变了自身的形态生理特征,而正是这种改变造成入侵生态型乌桕对UV-B辐射更为敏感。说明入侵物种乌桕是一种“一样精”(master of some)的物种,即在生境温和的条件下入侵物种乌桕容易入侵,而在环境胁迫的环境下,如UV-B辐射增强的情况下不利于入侵生态型乌桕的入侵。同时,在O_3和CO_2浓度同时升高的条件下,入侵生态型乌桕的总生物量明显优于本土生态型乌桕,并且两者的总生物量差异明显高于对照组,而在O_3浓度单独升高的条件下,入侵和和本土生态型乌桕的总生物量没有显著差异,甚至入侵生态型乌桕的叶片数显著低于本土生态型乌桕。O_3和CO_2浓度同时增加在本试验中是一种适宜植物生长的环境,因此结果进一步证实入侵种乌桕属于一种“一样精”的植物。3. O_3浓度或UV-B辐射单独升高均会对植物造成不利的影响,而CO_2浓度升高或模拟氮沉降都能够促进植物的生长。O_3与CO_2在植物生长的初期存在显著的交互作用,即O_3和CO_2浓度同时增加的情况下植株的生长表现优于CO_2浓度单独升高条件下的植株。O_3与UV-B同样存在显著的交互作用,UV-B辐射增强会消减O_3浓度升高对植株生长造成的负效应,或是增强植物对O_3的耐受性。O_3与氮沉降不存在明显的交互作用,两者对植物生长的影响只是简单的加和效应。4.在环境控制箱法中,O_3浓度升高显著降低了入侵生态型乌桕的根冠比,而对本土生态型乌桕的根冠比的影响不显著。在开顶式同化箱法中,两种生态型乌桕单一种植时,O_3浓度升高对入侵和本土生态型乌桕的根冠比没有显著影响,而混合种植时,O_3浓度升高对入侵和本土生态型乌桕的根冠比均显著减少。5.入侵物种乌桕的总生物量、根生物量和叶片数对CO_2浓度升高的响应明显,而CO_2浓度升高对本土伴生物种的生长没有显著影响。结果说明CO_2浓度升高能够增强入侵物种的竞争力,这与资源波动假说的理论是一致的:可利用资源的提高能够促进外来植物入侵。6.氮沉降能够显著减小入侵和本土生态型乌桕的叶生物量和根生物量差异,但是依旧不会改变入侵和本土生态型乌桕的竞争格局,即在对照或模拟氮沉降处理的情况下入侵生态型乌桕的竞争力均大于本土生态型乌桕。此外,氮沉降也能降低本土和入侵生态型乌桕的根冠比。7. O_3与不同氮沉降模式对入侵和本土生态型乌桕生长差异的影响存在显著的交互作用。O_3浓度增加能够加剧入侵和本土生态型乌桕对土壤中有效资源的竞争。试验过程中只在中期模拟氮沉降(Middle)或模拟随机氮沉降(Random)的处理相比模拟均匀氮沉降(Uniform)处理更利于入侵植物入侵。结果说明短时间内的资源波动变异越大,比单一地提高可利用资源更能发挥入侵植物对资源的高效竞争能力。全文结论:1.入侵物种乌桕在入侵地成功入侵存在两方面的原因:入侵物种在入侵生境之前就存在很强的竞争力,同时在入侵生境之后,由于外界环境的变化而发生了适应性进化,使得其进一步提升了入侵力。2.入侵物种乌桕在适宜环境下容易发生入侵,而在胁迫的环境下不易成功入侵。同时,胁迫的环境条件下会加剧种内或种间对有效资源的竞争。3.可利用资源增加能够促进入侵植物的入侵,同时可利用资源波动变异越大,越能发挥入侵植物的竞争优势。4.减少根冠比,即减少根部资源分配促进地上部分生长,这可能是植物在面对外界环境变化(无论是有效资源增加还是胁迫压力加大)的一种应对策略。
[Abstract]:Plant invasion is an important part of global change, closely, and other global change factors interaction, are inseparable. Explore intrusion response of plants to global change factors, to gain insight into the changes in physiological ecology of invasive plants, has important significance for monitoring plant invasions. The concentration of carbon dioxide (C02) and ozone (O_3) concentration increase of ultraviolet (UV-B) radiation intensity and nitrogen deposition is an important manifestation of current global changes. These changes in the external environment both growth and reproduction of individual plants, or succession of changes of community structure and ecosystem will be affected directly or indirectly. In addition, environmental factors also change often influence each other, thus influence the change of two and above environmental factors on plants may have a non additive effect. However, so far, for The interaction effect between these four kinds of environment factors on plant is still not clear, especially for the study of invasive plants is very rare. The invasive plants can successfully invade new areas, one of the reasons may be due to invasive plants than the local species itself has a strong competitive power, on the other hand may be due to invasive plants by the introduction of new habitat is influenced by the environmental factors and the occurrence of adaptive evolution and improve the competitiveness. Therefore, the invasion of invasive species and its associated species response or invasive species invasion and local ecological change on ecological environmental factors may also exist obvious differences. This paper focuses on the O_3 and other environmental factors (CO_2 UV-B, and nitrogen deposition) interaction with main Sapium sebiferum as tested materials, using the method of indoor environment control box, explore the invasive species in Ukraine Tallow and 3 kinds of local associated species, and response to the intrusion and the local ecotype of 03 and CO_2 concentration of Chinese tallow. Using the method of outdoor open top assimilation box, to explore the 03 concentration and enhanced UV-B radiation, and 03 concentration and different nitrogen deposition simulation effect on the soil ecological invasion and growth performance of Chinese tallow the main results are as follows: 1. by invasive plants and native Sapium growth performance comparison of 3 companion species, invasive species found Sapium has obvious growth predominance, and has concentrated low tannin content. Through the invasion and local ecological type of single planting and mixed planting of Sapium sebiferum growth contrast, find intrusion ecotype in biomass plant Sapium, higher growth indexes than the local ecological tallow, especially in mixed planting, ecological invasion of local ecological competition compared to Chinese tallow tallow Competitive advantage is more obvious. The results show that in the new environment of Sapium is introduced, the result of adaptive evolution, the resource allocation mechanism also changed, which is originally used for the part of the production of high consumption of the secondary metabolites of resources are transformed into low consumption for the growth of plants, which not only invasive species relative to native species associated with with tallow very strong competitive power, and relative local ecological ecological invasion of Sapium sebiferum also competitive advantage. Sapium results verify the evolutionary hypothesis.2. enhanced competitiveness with respect to the local ecological invasion of Sapium ecotype responses to UV-B radiation intensity increased Sapium is more sensitive, in addition, enhanced UV-B radiation, two ecotypes have obvious opposite changes in leaf litter quantity that is, the local ecotype tallow leaves litter increased significantly, leaf litter and invasion ecotype decreased significantly the tallow. Can change soil nutrient cycling processes, the influence of exotic plants invasion performance further. Thus, in order to successfully invade the previous ecological invasion of Sapium new habitat, may change the morphological and physiological characteristics of its own, and it is this change caused by the invasion of ecotype is more sensitive to UV-B radiation tallow. Invasive species is a kind of "refined tallow" (Master of some) species in habitats under mild conditions and easy invasion of invasive species in Sapium, environmental stress conditions, such as enhanced UV-B radiation condition is not conducive to the invasion of the ecological Sapium. At the same time, also increased in O_3 and CO_2 concentration conditions, the total ecological invasion of Sapium sebiferum the biomass was significantly better than the local ecological tallow, total biomass and the difference between the two was significantly higher than the control group, separately under elevated O_3 conditions, and the soil ecological invasion Ukraine There was no significant difference between the total biomass of the seed, leaf number and invasion was significantly lower than the local ecological ecological Sapium.O_3 and CO_2 increased with concentration of tallow in this experiment is a suitable plant growth environment, so the results further confirmed the plant.3. concentration of O_3 or UV-B radiation invasive species belongs to a kind of "a kind of Chinese tallow fine" alone the increase will cause adverse effects on plants, and higher concentration of CO_2 or simulated nitrogen deposition could promote the growth of.O_3 and CO_2 plants significantly in the early stage of plant growth, namely O_3 and CO_2 concentration at the same time increased growth performance is better than that of CO_2 concentration under the condition of single plant and plant to increase.O_3 and UV-B conditions under the same significant interaction, enhance the O_3 concentration may reduce the negative effect on plant growth of UV-B radiation, or enhance plant tolerance to O_3.O_3 with nitrogen The settlement does not exist obvious interaction between the two, the effect on the growth of just.4. simple additive effect in environmental control box, O_3 concentration significantly reduced the invasion of the root shoot ratio of Sapium ecotypes, but had no significant effects on the local ecological Sapium root shoot ratio. In the open top box method in two kinds of assimilation. Single plant Sapium ecotypes, elevated O_3 concentration on invasion and local ecotype of Sapium sebiferum root shoot ratio had no significant effect, and mixed planting, O_3 concentration increased the total biomass of the intrusion and the local ecotype Sapium sebiferum root shoot ratio were significantly reduced in the.5. invasion of Chinese tallow, root biomass and leaf number in response to elevated CO_2 obviously, the CO_2 concentration of native species associated with growth had no significant effect. The results show that elevated CO_2 concentration can enhance the competitiveness of invasive species, this hypothesis and the resource fluctuation theory is The same: leaf biomass and root biomass of different available resources can promote the increase of invasive plant.6. nitrogen deposition can decrease the invasion and local ecological tallow, but still does not change the invasion and local ecological tallow competition pattern, namely in the control or simulation of nitrogen deposition of Sapium ecotype intrusion case competitive are larger than the local ecotype of Sapium sebiferum. In addition, nitrogen deposition can also reduce the local invasion and ecological effects of.7. O_3 Sapium root shoot ratio and different nitrogen deposition patterns of growth differences on invasion and local ecological deposit increase to increased Sapium invasion and local ecological competition on the effective resources of Sapium sebiferum in soil.O_3 concentration was significant interaction. The test process only in the middle of simulated nitrogen deposition (Middle) or random simulation of nitrogen deposition (Random) treatment compared with the simulated nitrogen deposition (Uniform) at the uniform Science is more conducive to invasive plants invasion. Results show that resource volatility in a short period of time is bigger, better than the single available resources can play high competitive ability of invasive plant resources. Conclusion: 1. species of Sapium invasion success there are two aspects of the reason: in the invasion of invasive species in invaded habitats before there is a strong competitiveness, at the same time in the habitat, due to changes in the external environment of the adaptive evolution, which further enhance the invasion force.2. prone to invasion of invasive species of Sapium sebiferum in suitable environment, and in the stress environment is not easy to successful invasion. At the same time, the environmental stress conditions exacerbate internal or interspecific competition for resources on the effective utilization of resources increased.3. can promote the invasion of invasive plants, at the same time the use of resource volatility is larger, more invasive plants can play a competitive Potential.4. reduces root shoot ratio, that is, reducing root resource allocation and promoting aboveground growth. This may be a coping strategy for plants in the face of external environmental changes (whether effective resources increase or stress stress increases).

【学位授予单位】：南京农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q948.1

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