【作者】 郭宝华；

【导师】 范少辉；

【作者基本信息】 中国林业科学研究院 ， 森林培育， 2014， 博士

【摘要】 生态化学计量学，以研究多重化学元素平衡关系为目标，通过研究主要化学元素（C、N、P等）的计量关系来揭示有机体的特性及行为与生态系统间的相互关系，可以把个体、群落、景观等不同层次联系起来，揭示植物生长特征及其限制性因子相互关系。这种方法可能为毛竹林生产力与主要化学元素定量关系的研究开辟新途径。为此，本文以我国主要毛竹分布区（福建、江西、浙江、湖南等）毛竹林植被-土壤-凋落物系统为研究对象，试图通过对不同年龄（1~6年）、不同生产力水平（I：30000±1000kg·hm-2·a-1、II：34000±1000kg·hm-2·a-1、III：37000±1000kg·hm-2·a-1、IV：42000±1000kg·hm-2·a-1、V：47000±1000kg·hm-2·a-1）和不同分布区域毛竹林的C、N、P含量及其化学计量特征的系统研究，阐明毛竹个体、毛竹林分和区域尺度上毛竹林植被的生态化学计量特征，揭示生态化学计量学对毛竹林生产力的影响，为毛竹林科学经营提供理论依据。研究的主要结果是：1、在个体尺度上，毛竹同一器官C、N、P含量和C:N、C:P、N:P比值，随着毛竹年龄的增大而呈现显著差异。不同年龄的毛竹生产力不同，养分分配数量和比例也不同，符合“生长速率”假说。N和P含量随着年龄的增加呈先降低后升高的趋势。不同年龄毛竹C:N和C:P均以3年生毛竹林最高；N:P比值3年生毛竹林最低，5年生毛竹林中最高，反映了3年生毛竹代谢旺盛，扩鞭能力强，鞭芽活力高，具有较大的潜在生产力，N元素的供给可能对3年生毛竹林有较大影响；5年生毛竹N:P最高，反映了五年生毛竹单位P元素对N的固持效率最高，此时采伐P元素的利用效率已达到最大。2、在林分水平上，不同生产力水平下的毛竹林植被及土壤C、N、P含量有显著差异，但是植被层和土壤层C:N、C:P、N:P的差异程度不一致，植被层的差异未达到显著水平，土壤层的差异达到显著水平，毛竹林植被和土壤未表现出显著的相关性。（1）不同生产力水平毛竹林植被层C、N、P贮量存在显著差异，但是C:N、C:P、N:P的差异未达到显著水平；不同生产力水平下毛竹叶片N:P为12.60-13.69，变异系数为12.31%，反映了毛竹林主要养分元素的计量比随着生产力水平的不同在一个小的范围内波动，具有内在的稳定性，符合“内稳性”假说，同时N:P＜14也反映了研究区毛竹林生长主要受到N元素的限制。（2）不同生产力水平毛竹林土壤有机碳、N、P、H-N、A-P分布格局发生明显变化，其计量比值的差异也达到了显著水平。其中，N:P为4.50-13.89，随着生产力的降低呈升高的趋势。土壤N:P比值变化同生产力变化过程有较好的同步性，其对毛竹林生产力的变化与叶片相比具有更强的敏感性，有可能成为未来竹林退化诊断的生态指示指标。毛竹林土壤主要养分计量值与植被养分计量值的相关性未达到显著水平，但是竹叶养分计量比与林地主要养分的计量比有较大的相关系数，反映了林地养分含量及化学计量比值的变化，在一定程度上影响了植株的养分含量及其计量比。3、在区域尺度上，毛竹林主要养分计量特征存在明显分异。（1）沿纬度方向的变化规律：毛竹叶片N、P含量以及N:P比值随纬度升高而升高，C:N和C:P随纬度升高而降低；凋落物中N含量以及C:P和N:P随纬度升高而增大，P含量和C：N随纬度升高而降低；土壤层C、N含量以及C:P、N:P随纬度升高而增大，P含量、C:N随着纬度升高而降低。（2）沿经度方向的变化规律：毛竹林叶片N、P含量随经度升高而降低，C:N、C:P以及N:P比值随经度升高而增大；凋落物中N、P含量随经度升高而增大，C:N、C:P和N:P比值均随经度升高而减小；土壤层C、N、P含量以及C:P、N:P比值随经度升高而减小，C:N比值随经度升高而增加。（3）区域毛竹林生态化学计量特征：叶片C:N比为25.32，C:P比为143.36，N:P为5.66；凋落物C:N比为30.89，C:P比为593.16，N:P为19.20；土壤中C:N比为12.71，C:P比为54.24，N:P为4.27。当N:P<14时，受N元素限制，14<N:P<16时，同时收N和P元素限制；N:P>16时，受P元素限制。本研究所得数据表明，我国毛竹林生长主要受N元素的限制，P元素限制较少。综上所述，毛竹主要生态化学计量值在个体水平上符合“生长速率假说”，在林分水平上符合“内稳性假说”，在区域水平上表现出明显的分异性。叶片N:P说明本研究区毛竹林生长主要受到N元素的限制，受P元素的限制较小，且土壤N:P比值对毛竹林生产力变化有较强的指示性。在现有经营水平上，林地基本能够满足毛竹林对P元素的需求，应加强N元素的输入与管理，但在具体缺P林地或区域亦可适当增加P元素的输入，以缓解本区域N元素限制，提高毛竹林生产力。更多还原

【Abstract】 New emerging ecological stoichiometry aims to study the balance of multiple chemicalelements by studying stoichiometry of the main chemical elements (C, N, P, etc.) to reveal therelationship between the characteristics and behaviours of organisms and ecosystems, whichcould link different levels of individuals, community and landscape together to reveal thegrowth characteristics of plants and the important role of limited factors. This method mayopen a new approach to quantitatively describe the relationship between productivity and mainchemical elements in Phyllostachys pubescens forest. Thus, in this study, in mainPhyllostachys pubescens distribution areas (Fujian, Jiangxi, Zhejiang, Hunan, etc),bamboo-soil-litter was considered as research objects to study C, N and P content and theirstoichiometry in Phyllostachys pubescens forest of different ages (1-6years), differentproductivity levels (I:30000±1000kg·hm-2·a-1, II:34000±1000kg·hm-2·a-1, III:37000±1000kg·hm-2·a-1, IV:42000±1000kg·hm-2·a-1, V:47000±1000kg·hm-2·a-1) and differentdistribution areas, further to reveal the stoichiometry characteristics of individual, communityand regional distribution of bamboo forest, and to illustrate the relationship betweenstoichiometry and productivity levels in Phyllostachys pubescens forest, which could providebasic theory for scientifical management. The main results are:1. Individually, C, N, P content and C:N, C:P, N:P of same organ showed significantdifference with the increase of age. Productivity, the nutrient quantity and ratios differed fromdifferent ages, which was consistent to “growth rate” hypothesis. N and P content increasedfirst and then decreased with the increasing age. C:N and C:P were both highest at age5, N:Pwas lowest at age3, and was highest at age5, indicating3-year old Phyllostachys pubescenshad strong metabolism, rizhome expansion, high potential productivity, and N supply mighthad significant effect on3-year Phyllostachys pubescens forest; N:P was highest at age5, indicating bamboo at age5had highest holding efficiency of N, harvesting bamboo at this time,P utilization efficiency was highest.2. The difference of plant and soil C, N and P content was significant in Phyllostachyspubescens forest of difference productivity levels at stand level, but the difference was notconsistent between plant and soil C:N, C:P, N:P. Plant C:N, C:P, N:P of was not statisticallysignificant difference, while soil C:N, C:P, N:P was statistically significant difference. Thecorrelation between plant and soil was not significant.(1) Plant C, N and P content was statistically significant different in Phyllostachyspubescens forest of different productivity levels, but the difference of C: N, C: P, N: P did notreach a significant level. N:P of leaves was12.60-13.69in Phyllostachys pubescens forest ofdifferent productivity levels, and coefficient variation was12.31%, indicating stoichiometry ofmain elements fluctuated in a small range along with different productivity levels inPhyllostachys pubescens forest, which was in line with “internal stability” hypothesis.Meanwhile, N: P <14suggested N was the limited element in Phyllostachys pubescens forestin study areas.(2) Distribution of soil organic matter, N, P, H-N and A-P showed significant changes, andthe difference of ratios of stoichiometry reached a significant level. N:P was4.50-13.89, whichdecreased with the increase of productivity. Changes of soil N:P was consistent with thechanges of productivity synchronously, which was more sensitive compared to leaves, andcould be the potential indication index to the degradation of Phyllostachys pubescens forest.The relationship between soil stoichiometry and plant stoichiometry was not significant, butthe coefficient leaf stoichiometry was higher that of soil stoichiometry, indicating the changesof soil nutrient content and stoichiometry affected bamboo nutrient content and theirstoichiometry to some extent.(3) The number of the significant correlation between nutrient cycling characteristic andplant, soil was9for N:P,8for C:P, and2for C:N, respectively, in Phyllostachys pubescensforest of different productivity levels, showing nutrient cycling characteristic wassignificantly affected by C and P. 3. Regionally, the stoichiometry characteristic of main nutrients showed obviousdifferentiation.(1) Change law along with latitude: leaf N and P content and N:P increased with theincrease of latitude, and C:N and C:P decreased with the increased of latitude; litter N content,C:P and N:P increased with the increase of latitude, and P content, C:N decreased with theincrease of latitude. Soil C, N content, C:P and N:P increased with the increase of latitude, andP content and C:N decreased with the increase of latitude.(2) Change law along with longitude: leaf N and P content deceased with the increasinglongitude, and C:N, C:P and N:P increased with increasing longitude; litter in N, P contentincreased with increasing latitude, and C: N, C: P and N: P decreased with increasing longitude;soil layer C, N, P content and C: P, N: P decreased with increasing longitude, and C: N ratioincreased with increasing longitude.(3) Regional distribution of ecological stoichiometry characteristics in Phyllostachyspubescens forest: leaf C: N, C: P and N: P were25.32,143.36and5.66, respectively; litter C:N, C: P and N: P were30.89,593.16, and19.20, respectively; soil C: N, C: P and N: P were12.71,54.24and4.27, respectively. When N:P<16, Phyllostachys pubescens forest was limitedby N; while14<N:P<16, Phyllostachys pubescens forest was limited by both N and P; andN:P>16, Phyllostachys pubescens forest was limited by P. Data in our study indicatedPhyllostachys pubescens in China was mainly limited by N, seldom by P.In summary, in the individual level values of the major ecological stoichiometry inPhyllostachys pubescens was in line “growth rate hypothesis”; in the community level thevalues were in line with “internal stability” hypothesis, showing obvious differentiation onregional scale. Leaf N: P illustrated the growth of Phyllostachys pubescens forest was mainlylimited by N, rather than P, and soil N:P had strong indication to productivity changes inbamboo forest. Based on current management level, bamboo forest could meet the basic Pdemand, thus N input and management should be enhanced. However, increase P input in Plimited areas could alleviate N limitation and increase stand productivity.更多还原