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| 飞机草入侵地种群和原产地种群与两地本地近缘种竞争能力的比较研究 | |
| Alternative Title | Differences in interspecific competition ability among invasive and native populations of Chromolaena odorata and its native congeners from different ranges |
| 秦瑞敏 | |
| Thesis Advisor | 冯玉龙 |
| 2011-12 | |
| Degree Grantor | 中国科学院研究生院 |
| Place of Conferral | 北京 |
| Degree Discipline | 生态学 |
| Keyword | 飞机草 化感作用 生物阻抗假说 新武器假说 Eica假说 |
| Abstract | 外来物种入侵已成为一个全球性问题，成为威胁生物多样性和生态环境的一个重要因素。目前有关外来入侵植物入侵成功机制研究很多，但很少有一个理论或假说能够很好的解释外来植物为什么具有如此强的入侵能力。飞机草（Chromolaena odorata L.）是我国危害最严重的外来入侵植物之一，本实验以飞机草入侵地种群、原产地种群和两地本地种（水泽兰 Eupatorium stoechadosmum、白头婆 E. japonicum和墨西哥本地种）为材料，在西双版纳同质种植园中两个肥力水平下开展种间竞争实验，结合培养皿中种子萌发实验，验证生物阻抗假说、增强竞争能力的进化（EICA）假说和新武器假说。我们假设：（1）飞机草竞争能力强于入侵地中国本地种，但与墨西哥本地种差异不显著；（2）引入后飞机草发生了增强竞争能力的进化；（3）与原产地本地种相比，入侵地本地种对飞机草化感作用更敏感；（4）养分有效性增加能提高飞机草对本地种的竞争优势。种间竞争实验结果表明，（1）飞机草竞争能力在高肥下强于中国本地种但与墨西哥本地种没有差异。飞机草（不论是入侵地种群还是原产地种群）在高肥下株高、叶生物量、根生物量和总生物量响应竞争降低的幅度显著低于中国本地种，但大部分参数降低的幅度与墨西哥本地种无显著差异。（2）中国本地种虽然根较大，有利于地下资源的吸收和利用，但竞争能力低于墨西哥本地种。与墨西哥本地种相比，在高肥下中国本地种具有更高的根生物量分数，但根生物量、茎生物量、叶生物量和总生物量响应竞争降低的幅度更高。（3）飞机草入侵地种群竞争能力强于原产地种群，飞机草来到入侵地后发生了增强竞争能力的进化，支持EICA假说。与原产地种群相比，飞机草入侵地种群冠幅、茎生物量、根生物量和总生物量响应竞争降低的幅度显著偏低。将中国7个本地种和墨西哥8个本地种种子分别在0%、0.25%、1.25%和2.5%四个浓度的飞机草叶片水提液下进行萌发。结果表明，中国本地种对飞机草化感物质更敏感，而墨西哥本地种不受影响或受影响小。中国本地种种子发芽率、发芽速率、胚根长度和胚轴长度受飞机草化感作用影响显著高于墨西哥本地种。本研究显示，飞机草入侵成功的原因可能有如下四个方面：（1）飞机草在入侵地遇到的土著种比原产地的竞争能力差，支持生物阻抗假说。（2）中国本地种对飞机草新武器——化感物质更敏感，在入侵地飞机草通过化感物质成功入侵，支持新武器假说。（3）飞机草在高肥条件下发生了增强竞争能力的进化，支持EICA假说。（4）飞机草对入侵地本地种具有先天的的竞争优势。本研究还暗示，养分有效性减少有利于减缓飞机草入侵危害。但本研究用的飞机草种群数量和本地种的数量都较少，需要用更多的入侵植物种群和本地种开展竞争实验来探讨EICA、两地本地种对飞机草竞争能力的差异和新武器假说等与飞机草入侵性的关系。 |
| Other Abstract | Biological invasion is a global problem, which becomes a key factor to threaten biodiversity and ecological environment. However, there is not a theory or a hypothesis that can clearly explain why invasive species have so powerful ability to invade, although many related studies have been conducted. Chromolaena odorata is one of the most noxious invasive species in China. To test Biotic Resistance Hypothesis, Evolution of Increased Competitive Ability (EICA) hypothesis and Novel Weapons Hypothesis, we used C. odorata, Eupatorium stoechadosmum, E. japonicum and a Mexican species as plant materials to conduct an interspecific competition experiment in a common garden, and then conducted a seed germination experiment in laboratory. We hypothesized that: (1) C. odorata has higher competitive ability than native species from China but not those from Mexico; (2) C. odorata has evolved higher competitive ability after introdution; (3) native species from invasive range are more susceptible to C. odorata’s allelochemicals than that from native range; (4) increasing nutrient availability enhances competitive ability of C. odorata relative to its congeners. In interspecific competition experiment, the results showed that (1) C. odorata had higher competition ability than China species, but similar competition ability with Mexico species. C. odorata (whether introduced or native) had smaller changes in leaf biomass, stem biomass, root biomass and total biomass caused by competition than the two China species at high nutrient, indicating There was no significant difference in above variables between C. odorata and Mexico species. (2) China species had higher ability to use underground resources due to higher root mass fraction, but had lower competitive ability than Mexico species. Changes in leaf biomass, stem biomass, root biomass and total biomass caused by competition was significantly higher in China species than in Mexico species at high nutrition level although China species had higher root mass fraction. (3) Invasive populations of C. odorata higher competitive abilility than native species. Decreases in crown diameter, stem biomass, root biomass and total biomass caused by interspecific competition were lower in invasive populations of C. odorata than in native populations at high nutrition level. In seed germination experiment, seven China native species and eight Mexico native species were germinated at different concentrations of aqueous leaf extract of C. odorata (0%, 0.25%, 1.25% and 2.5%). The results showed that native species from China are more susceptible to C. odorata’s allelochemicals than that from Mexico. Relative germination rate, relative germination speed, relative radicle length and relative hypocotyls length were significantly lower fin China species than in Mexico species. The index of allelopathic effect on germination rate for Mexico species was smaller than for China species. In conclusion, four factors contributed to invasion success of C. odorata. (1) Competitive ability of native species from introduced ranges was lower than that of the native from native range, reducing resistance to invasion. (2) Compared with species from native ranges, species from invasive ranges were more vulnerable to allelochemicals of C. odorata. (3) C. odorata evolved higher competitive ability in novel range, supporting EICA. (4) C. odorata had innate competitive advantage over natives in introduced ranges. Moreover, the study implied that decreasing soil nutrient availability may reduce competitive advantage of C. odorata over natives, alleviating invasion impacts. |
| Document Type | 学位论文 |
| Identifier | https://ir.xtbg.ac.cn/handle/353005/9690 |
| Collection | 西双版纳热带植物园毕业生学位论文 |
| Recommended Citation GB/T 7714 | 秦瑞敏. 飞机草入侵地种群和原产地种群与两地本地近缘种竞争能力的比较研究[D]. 北京. 中国科学院研究生院,2011. |
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| 飞机草入侵地种群和原产地种群与两地本地近（1057KB） | 开放获取 | CC BY-NC-SA | Application Full Text | |||
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