氮磷供应条件对盐地碱蓬生长及生态化学计量特征的影响
文献类型：学位论文
| 作者 | 冉越男
|
| 学位类别 | 硕士 |
| 答辩日期 | 2017-05-07 |
| 授予单位 | 中国科学院大学 |
| 授予地点 | 北京 |
| 导师 | 于君宝 ; 王光美 |
| 关键词 | 盐地碱蓬 氮磷供应比例 生长时期 供应量 生态化学计量特征 |
| 学位专业 | 环境科学 |
| 中文摘要 | 受人类活动影响，黄河三角洲滨海湿地氮磷供应条件，包括氮磷供应比例和总供应量，均已发生较大改变。生态化学计量学是研究植物对营养条件改变响应的重要研究方法。受自身养分需求规律及结构特点调节，植物生态化学计量学特征随营养条件和生长时期的不同而变化，器官之间亦存在差异。本研究以黄河三角洲优势植物盐地碱蓬（Suaeda salsa）为研究对象，通过野外控制实验，分析氮磷供应比例和供应量对其不同生长时期生长状况及各器官C、N、P化学计量特征的影响，比较氮磷供应条件和生长时期对其生态化学计量特征影响强度的差异，以探讨盐地碱蓬对该区氮磷供应条件改变的响应。结果表明： （1）本研究条件下，氮磷供应总量对盐地碱蓬形态指标、总生物量及各器官生物量分配均有显著影响。低供应量下盐地碱蓬在生长前期株高较高，但基径较小，叶片生物量分配比例较低，至生长后期冠幅显著较低，根系生物量占比显著较高，生物量较中、高供应量水平下显著较低。中高供应量水平下各指标差异均不显著。氮磷供应比例对盐地碱蓬形态指标影响不显著，在高供应比例下叶片生物量分配比例显著较高，对生物量的影响与供应量交互作用显著，低供应量水平时高供应比例下生物量显著较高。 （2）氮磷供应条件变化下，盐地碱蓬各器官C含量变异程度较低，N、P含量变异程度较高；N、P含量分别在根、叶中变异程度最低；C:N的变异程度在根中最低，茎中最高；C:P和N:P的变异程度在叶片中最低，根中最高，表现出明显的器官差异。各器官元素化学计量特征的变异程度均表现为生长前期显著低于生长中、后期，其对外界养分环境的响应程度是随生长时期不断积累的过程。 （3）氮磷供应比例和供应量对盐地碱蓬各器官C含量的影响较小；在各生长时期，盐地碱蓬各器官N含量及C:N、叶片P含量、叶片C:P均受供应量影响更大，根P含量、根C:P则主要受氮磷供应比例影响。各器官N:P、茎P含量及茎C:P在生长前期受供应量影响更大，在生长中后期后受供应比例影响更高。随生长时期推移，氮磷供应比例对各器官N含量及C:N的影响强度逐渐降低，对P含量、C:P及N:P的影响强度逐渐升高，氮磷供应量对各器官N含量及C:N的影响强度逐渐升高，对N:P的影响强度逐渐降低，对P含量和C:P的影响则呈先升高后降低的波动趋势。氮磷供应比例和供应量对盐地碱蓬生态化学计量特征影响的相对强弱随生长时期推移呈明显变化，在某一生长时期的单次取样会得出片面结论。 （4）盐地碱蓬各器官N含量随供应量和供应比例增加基本呈上升趋势，P含量随供应量增加亦逐渐上升，随供应比例增大而降低或无明显变化，在不同生长时期和器官间存在差异。各器官C:N和C:P对供应量和供应比例的响应，除方向相反以外，分别与N含量和P含量的响应情况基本一致。各器官N:P随氮磷供应比例的升高和供应量的增加，均呈上升趋势，体现了盐地碱蓬对黄河三角洲自然条件下氮限制状态的长期适应，使其对N供应水平的提高相对P更为敏感。 （5）在本研究设置9倍供应比例和供应量差异的情况下，比较供应条件和生长时期对盐地碱蓬各器官生态化学计量特征的影响强度，体现出明显的元素差异和器官差异。各器官C含量主要受生长时期影响，P含量则受供应条件影响更强。叶N含量受供应条件影响更高，根N和茎N含量则受生长时期影响更大。供应条件对叶C:N、叶C:P、茎C:P、茎N:P以及根N:P影响较高，生长时期则对叶N:P、茎C:N、根C:N和根C:P影响更大。就器官比较而言，盐地碱蓬叶片生态化学计量特征受供应条件影响更大，而根生态化学计量特征则受生长时期影响较高。 |
| 英文摘要 | The nitrogen（N）and phosphorus（P）status, including N:P supply ratio and overall supply level，has changed greatly in Yellow River Delta coastal wetland with increasing human disturbance. Ecological stoichiometry is an excellent research tool to study the plant response to nutrient status variation. Influenced by the nutrient demand characteristics and structure feature, plant ecological stoichiometry characteristics will change along with the variation of nutrient status and growth phase, and differ in different organs. In this research, the response of Suaeda Salsa, a dominant plant in Yellow River Delta, to the variations of N and P supply status was studied through a field control experiment. Three N:P supply ratios combined with three overall supply levels were set in the experiment. The respective effect of N:P supply ratio and overall supply level on the growth vigor，the C, N, P concentrations and C:N:P ratios in different organs, were examined at three growth phases. The relative impact strength of N and P supply status and growth phase on the stoichiometry of specific organ was compared as well. The results indicated that: (1) The morphological traits, including plant height, basal diameter and crown size, as well as total biomass and biomass allocation of S.salsa were significantly related to overall nutrient supply level. Growing at low overall supply level, the plant was taller and thinner with a lower leaf biomass allocation in early vigorous growth phase; when come to later growth phase, it had smaller crown size with higher root biomass allocation and smaller total biomass. However, there was no significant change of all indicators between medium and high supply level. The N:P supply ratio alone had no significant effect on the morphological traits but had significant interaction with supply level on total biomass. The biomass increased significantly at high N:P supply ratio under low overall supply, with leaf biomass allocation increased simultaneously. (2) Under changing N and P supply status, C concentration varied least in S.sala organs compared with N and P concentration. Among different organs, N concentration varied least in root, while P concentration varied least in leaf. As for the C:N:P ratios, root C:N varied least while stem C:N varied most. Variation of both C:P and N:P was least in leaf and most in root. This result showed a significant organ difference of their stoichiometry characters responding to the changing N and P supply status. In addition, the variation of C, N and P stoichiometry was always the least in early growth phase and became greater over time, indicating that the response of C, N and P stoichiometry to nutrition condition was a cumulative process. (3) The N:P supply ratio and overall supply level had slight impacts on the C concentration in S.sala organs. At all growth phases，the tissue N concentration , C:N and the leaf P concentration as well as the leaf C:P were mainly determined by the overall supply level, while the root P concentration and root C:P depended most on the N:P supply ratio. The main factor of the tissue N:P, stem P concentration and stem C:P varied at different growth phases. Overall supply level affected them more at early growth phase, while N:P supply ratio had a greater influence at middle and late growth phase. The impact strength of N:P supply ratio on tissue N concentration and C:N decreased over time while increased on P concentration, C:P and N:P. On the contrary, the impact strength of overall supply level showed opposite trend on N concentration, C:N and N:P over time. As for its impact strength on the P concentration and C:P, it increased first and then decreased. The relative impact strength of N:P supply ratio and overall supply level on stoichiometry characters varied obviously over time, pointing to that single sampling at specific phase may result in incomplete conclusion. (4)With the rise of overall supply level, the tissue N, P concentration and N:P increased while the tissue C:N, C:P ratio decreased significantly. With the increase of N:P supply ratio, the tissue N concentration, C:P and N:P ratio rose while C:N declined; the P concentration in specific organs decreased or kept stable, which differed among growth phases and organs. With the rise of N:P supply ratio and overall supply level, the N:P in all organs tended to increase. This consistent tendency in tissue N:P may reflect the long-term adapting strategy of S.salsa in Yellow River Delta where was mainly N-limited，which made it more sensitive to the increase of the N supply than to P supply. (5)When compared the impact strength of N and P supply condition and growth phase on the stoichiometry of specific organ of S.salsa under the circumstance that being 9-folds differences of N:P supply ratio and overall supply, the result showed obvious organ and elemental difference. Growth phase still contributed most to the variations of tissue C concentration, while N and P supply status impacted more on tissue P concentration. Leaf N concentration was more influenced by N and P supply status; however, root and stem N concentration were more impacted by growth phase. The N and P supply status had higher impact on leaf C:N，leaf C:P, stem C:P，stem N:P and root N:P, while growth phase influenced more on the leaf N:P, stem C:N, root C:N and root C:P. Compared within specific organs, leaf stoichiometry characteristics was influenced more by N and P supply status, while root stoichiometry characteristics was impacted more by growth phase. |
| 学科主题 | 环境生态学 |
| 源URL | [http://ir.yic.ac.cn/handle/133337/21985]  |
| 专题 | 中科院烟台海岸带研究所知识产出_学位论文 烟台海岸带研究所_滨海湿地实验室 |
| 作者单位 | 1.中国科学院烟台海岸带研究所 2.中国科学院大学 |
| 推荐引用方式 GB/T 7714 | 冉越男. 氮磷供应条件对盐地碱蓬生长及生态化学计量特征的影响[D]. 北京. 中国科学院大学. 2017. |
入库方式： OAI收割
来源：烟台海岸带研究所
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