不同恢复模式缺苞箭竹的生长特征及其对林地碳库与氮库的影响
文献类型：学位论文
| 作者 | 万明利 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-05-01 |
| 导师 | 刘庆 |
| 关键词 | 缺苞箭竹 种群结构 生物量 碳库 氮库 Fargesia denudata population structure biomass carbon stock nitrogen stock |
| 其他题名 | Growth Characteristics of Fagisia denudata Restored in Different Models and Its Effects on Soil Carbon and Nitrogen Stocks |
| 中文摘要 | 环境因子对林木的生长发育具有重要作用。而同一物种对不同的环境条件也具有不同的适应策略。它们通过不同的生长策略，调节其形态和形态可塑性来适应不同的环境。同样，植物对生态系统功能的发挥具有重要的影响。本研究选择1983年在草坡、未郁闭人工林、次生林、暗针叶林下人工恢复的缺苞箭竹作为研究对象，同时也选择了天然更新的缺苞箭竹，分析不同恢复模式下缺苞箭竹的种群结构、生物量特征和光合特征。同时，本研究还选择了恢复和未恢复缺苞箭竹的草坡、次生林、暗针叶林作为对照，分析了不同恢复模式缺苞箭竹对林地土壤碳氮库的影响，具体结果如下： 通过20多年的恢复，不同恢复模式缺苞箭竹的种群结构和生物量特征差异明显。恢复于次生林和暗针叶林下的缺苞箭竹种群与天然更新种群和恢复于草坡和人工林下种群相比，其平均高度更高、竹秆更粗、分株的平均年龄更大、种群分化更严重。不同恢复模式缺苞箭竹种群的生物量分配格局也存在差异。这些结果表明通过人工恢复箭竹来恢复和扩大大熊猫栖息地是可行的，而且合适的扩展地是具有0.3 到 0.7郁闭度的森林；恢复于草坡的种群较恢复于次生林和暗针叶林下的种群可能需要更长的时间才能达到其最大高度。 不同恢复模式缺苞箭竹的光合特征也呈现出一定的差异。暗针叶林下恢复的缺苞箭竹其净光合速率最大，其次是次生林下恢复的种群，而草坡和人工林下恢复种群的净光合率相对较低。此外，次生林和暗针叶林下恢复种群的胞间CO2浓度也较草坡和人工林下恢复种群的高。但是气孔导度和蒸腾速率较草坡和人工林下恢复种群低。不同恢复模式缺苞箭竹的叶绿素荧光参数也存在差异。草坡恢复种群的F0、Fm值显著小于其它恢复模式种群的相应值。各种群间Yield、qP和qN的值也呈现差异。草坡恢复种群的叶绿素a 、叶绿素b和总叶绿素浓度都显著地低于其它恢复模式种群的相应值。但不同恢复模式种群的类胡萝卜素的含量和Chla/Chlb值差异不显著。这些结果表明：恢复于草坡和未郁闭的人工林下的缺苞箭竹，可能受到某种胁迫的干扰；而且缺苞箭竹在不同的恢复模式下，对不同环境的适应调节能力有限。 不同恢复模式缺苞箭竹对土壤各层有机碳浓度的影响存在差异。缺苞箭竹恢复总的影响是显著降低了草坡中土壤有机碳的贮量，而对次生林和针叶林土壤有机碳贮量无显著影响。缺苞箭竹恢复总体上降低了草坡、次生林和暗针叶林中土壤全N贮量，但效果不显著。缺苞箭竹恢复降低了草坡中的C/N比，但增加了次生林和暗针叶林中的C/N比值。缺苞箭竹恢复对林地矿质土壤的影响主要作用于表层0~20cm 土层。此外，缺苞箭竹对林地土壤的碳氮库进行了重新分配。这些结果表明恢复缺苞箭竹对林地的影响依赖于不同的恢复林地，而且缺苞箭竹恢复使该区的次生林和暗针叶林成为了“碳汇”。 在该区森林中，MBN浓度从4月到10月一直增加，这种趋势不受缺苞箭竹的影响。在不同的恢复模式下，缺苞箭竹恢复和取样时间对MBN都有显著的影响。虽然缺苞箭竹恢复在大多数时间都降低了林地DON的浓度，但对DON的总体影响并不显著。除暗针叶林外，缺苞箭竹恢复对NH4+-N和NO3--N的浓度都有显著影响。缺苞箭竹恢复对NI的影响显著，在不同的恢复模式下均降低了林地NI值。本研究的结果表明：缺苞箭竹是该区域生态系统N维持的重要因子；MBN在一定程度上弥补了系统因缺苞箭竹缺失而造成的不利影响。因此，恢复箭竹对该区森林生态系统N固持能力的提高具有重要作用。 土壤MBC从4月到10月单调增加。除9月的次生林外，林地的微生物生物量碳都随着缺苞箭竹的恢复而降低。缺苞箭竹恢复降低了草坡和次生林中的土壤DOC浓度，而对暗针叶林下DOC浓度的影响不明显。缺苞箭竹恢复还增加了草坡和暗针叶林地土壤中EOC浓度，而在次生林中这种作用只发生在生长季后期和生长季之后。不同恢复模式缺苞箭竹林下与其相应的对照相比，缺苞箭竹恢复对林地土壤TOC浓度的影响显著。缺苞箭竹恢复显著降低了草坡中TOC的浓度，但却显著地增加了次生林和暗针叶林中TOC的浓度。这些结果表明：一个系统中，箭竹和微生物生物量似乎是一种互补的关系，两种作用共同维持着系统中的碳素平衡；缺苞箭竹恢复降低了草坡和暗针叶林林地土壤有机碳的稳定性。 Environments were important to plant growth. Some clonal plants had different growth strategies to adapt different environments. In return, plant species also had important effects on the functioning of the ecosystem. In the present study, F. denudata restored in 1983 in grasslands, plantations, secondary forests and coniferous forests was selected. The way F. denudata restored in each stand was definded as a restoring model. Natural regenerated F. denudata was also selected to evaluate the restoring effects. Population structure, characteristics of biomass and photosynthesis of F. denudata restored in the models were studied. Grasslands, secondary forests and coniferous forests without F. denudata were also selected as references to evaluate the effects of F. denudata restored in grasslands, secondary and coniferous forests on soil carbon and nitrogen stocks. The results were follows: Over two decades, population structure and biomass characteristics of F. denudata restored in the models were changed obviously. F. denudata restored in secondary and coniferous forests were higher, thicker and differentiated more than natural regenerated and those restored in grasslands and those restored in plantations. Biomass allocation patterns of F. denudata restored in the models were different. The results suggested that expanding giant panda’s habitats was feasible by planting dwarf bamboo; forests with 0.3 to 0.7 canopy cover were the suitable area to expand or restore giant panda’s habitats; and that F. denudata restored in grasslands should take longer time to reach their full height than those restored in secondary and coniferous forests. Photosynthetic characteristics of F. denudata restored in the models were different. F. denudata restored in coniferous forests had higer net photosynthetic rate than others, followed by those restored in secondary forests. F. denudata restored in secondary and coniferous forests also had higher values of intercellular CO2 concentration than those restored in grasslands and plantations. But F. denudata restored in secondary and coniferous forests had lower values of transpiraton rate and stomatal conductance than those restored in grasslands and plantations. Each chlorophyll flurescence parameter of F. denudata restored in the models was different. F. denudata restored in grasslands had significantly lower values of F0 and Fm than others. F. denudata restored in grasslands also had significantly lower concentrations of chla, chlb, chl [a+b] of than others. But the differences of carotennoid concentration and chla/chlb were not significant. The results indicated that F. denudata restored in grasslands and in plantations might be interrupted by some stress factors; the adaptability of F. denudata was limited when confronting with different environments. F. denudata restored in the models had different effects on organic carbon, total nitrogen and C/N ratios in forest floors and mineral soils. Overall effects of F. denudata restoration on organic carbon stocks were decreasing in grasslands and not evident in secondary and coniferous forests, and the overall effects on total nitrogen stocks were slight decreasing in grasslands and secondary forests, and almost no effects in coniferous forests. The influences of F. denudata restoration on organic carbon and total nitrogen were stronger in forest floors than in mineral soils. The probable explanations of the effects were the differences of litter decomposition rate, amount of litterfall and longevity between F. denudata and other annual herbaceous species replaced by F. denudata restoreation. MBN, DON, NH4+-N, NO3--N and nitrogen availability (NI) were subject to temporal variability. MBN DON, NH4+-N, and NO3--N concentrations and NI were generally lower under F. denudata than in their references. Forest types had no significantly effects on soil N pools. The results indicated that F. denudata uptake was an important mechanism to conserve N, and that MBN offseted the impacts of F. denudata absence partly on N retention. So, restoring F. denudata may be an effective way to increase N retention capability of the ecosystems in the region. From April to Octorber, MBC contents were increasing. Except in secondary forests in September, MBC was decreased with F. denudata restoration. F. denudata restored in grasslands and secondary forests decreased soil DOC concentrations. But F. denudata restored in coniferous forests had not significant effects on DOC. F. denudata restored in grasslands and coniferous forests decreased soil EOC concentrations. But F. denudata restored in secondary forests only decreased soil EOC concentrations in later growing season and after the growing season. Comparing with their respective references, TOC concentration was significantly affected by restored F. denudata. F. denudata restored in grasslands decreased TOC concentrations significantly. But F. denudata restored in secondary and coniferous forests increased TOC concentration significantly. The results indicated that in a system, there was a complementary relationship between dwarf bamboo and microbe. They worked together and kept carbon balance. F. denudata restored in grasslands and coniferous forests decreased the stability of soil organic carbon. |
| 学科主题 | 植物学 |
| 语种 | 中文 |
| 公开日期 | 2010-11-24 |
| 页码 | 99 |
| 源URL | [http://210.75.237.14/handle/351003/246]  |
| 专题 | 成都生物研究所_生态研究 |
| 推荐引用方式 GB/T 7714 | 万明利. 不同恢复模式缺苞箭竹的生长特征及其对林地碳库与氮库的影响[D]. 2009. |
入库方式： OAI收割
来源：成都生物研究所
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