【作者】 洪滔；

【导师】 吴承祯；

【作者基本信息】 福建农林大学 ， 海岸带森林与环境， 2013， 博士

【摘要】 于2012年7月对福建东南海岸带山地—灵石山,以海拔梯度100m为间隔,将灵石山分9个海拔梯度进行优势树种与土壤调查与取样,参照《陆地生物群落调查观测与分析标准方法》测定灵石山不同海拔优势树种叶片、土壤的矿质元素含量、应用叶绿素仪(SPAD-502)测定优势树种叶片叶绿素含量、用CI-203激光叶面积仪测量其叶面积;用MAT253同位素比率质谱仪(Isotope Ratio Mass Spectrometer)与Flash EA1112HT元素分析仪(Elemental Analyzer)测试优势树种叶片的氮、碳同位素及不同海拔土壤氮、碳同位素;用LI-8100 土壤碳通量测量仪测定土壤碳通量。分析不同海拔优势树种叶属性特征;优势树种叶片氮同位素、碳同位素分布结构与差异;优势树种叶片氮、碳同位素对海拔梯度环境的响应特征;优势树种的矿质元素含量对叶片氮、碳同位素值的联合作用;不同海拔优势树种矿质元素含量对叶片氮、碳同位素分馏的影响;不同海拔优势树种叶片氮、碳同位素与土壤氮、碳同位素、土壤矿质元素、土壤碳通量等的相关性。从不同海拔梯度优势树种叶片稳定氮、碳同位素、叶片矿质元素、土壤稳定氮同位素以及土壤矿质元素等角度分析优势种叶片氮、碳稳定同位素特征及其对环境的响应,为构建“环境—植物—环境”系统机制提供重要理论基础,并对中亚热带海岸带的重要常绿阔叶林群落分布格局、生态系统的养分循环特征、退化生态系统恢复以及植被吸收氮沉降规律提供重要理论基础。研究结果显示:1、对灵石山多海拔连续出现的优势树种叶片矿质元素含量进行比较,C含量最高,Cu含量最低。乔木优势种的各个矿质元素含量规律基本相同,除Na受海拔差异的影响较大外,其他矿质元素受海拔因素影响均不明显;灌木优势种矿质元素差异没有表现出明显一致性规律。300m和400m海拔乔木与灌木树种间叶绿素具有显著差异,300m～700m海拔梯度乔木优势树种叶绿素在树种间具有极显著差异,200m～400m海拔的不同灌木优势树种间叶绿素差异达极显著水平。优势树种的叶面积均呈现出随海拔升高而降低的趋势,乔木与灌木优势种的SLA总体分布于0.011～0.027之间,基本呈现出随海拔升高而下降的趋势,同一海拔梯度乔木树种和灌木树种SLA具有显著差异。2、对灵石山优势树种叶片氮同位素进行分析,所测试的26种优势树种63份样品的δ15N值分布于-6.0405‰～0.472‰间,均值为-3.1025‰。不同功能型植物叶片δ15N的组成具有明显差异,乔木δ15N均值为-2.6538‰,高于灌木δ15N的均值-3.3991 ‰。优势树种δ15N随海拔高度变化表现为明显的二次曲线,在海拔100m～400m左右,植物δ15N均值大致随海拔升高而逐渐变轻,在海拔400m～900m左右转换为随海拔升高而变重,说明在灵石山全海拔梯度中,植物δ15N分馏在海拔400m左右产生转换。灵石山优势树种叶片δ15N因树种差异与海拔差异表现出较大变率。3、就优势树种叶片δ15N与矿质元素关系而言,乔木优势树种N和C/N对δ15N的影响最显著,Ca和Mn与δ15N相关性较好,而C、K以及Cu与三种乔木之间相关性不显著。灌木优势树种δ15N与Ca、P和Mg呈显著的正相关,与C/N呈显著的负相关。选择300 m与400 m海拔的6个乔木和灌木优势树种叶片δ15N值与矿质元素含量进行相关性分析,具有极显著相关性的有:δ15N与N、C/N;N与C/N;K与C;Mg与C、Ca;Mn与C、K、Ca;Cu与Fe,具有显著相关性的有:δ15N与P;Ca与C、K;Mn与Na、Mg;Cu与C、K;Zn与Ca、Mg、Mn。优势树种叶片δ15N与N以及C/N的相关性表明,灵石山优势种叶片δ15N的海拔差异可能与N的利用具有密切关系。4、灵石山优势树种叶片δ13C值分布于-27.4265‰～-35.984‰间,其中超过95%的δ13C值分布在-29‰～-35‰之间,均值为-32.4938‰。乔木δ13C的平均值为-31.6242‰,高于灌木δ13C的均值-32.5807‰。优势树种δ13C随海拔高度变化表现为二次曲线,各海拔优势树种叶片δ13C均值与海拔变化显著相关,海拔100m～300m,优势树种δ13C均值随海拔升高逐渐变轻,在海拔300m～900m则变为随海拔升高变重,表明在灵石山不同海拔梯度中优势树种δ13C分馏在海拔300m就产生。对多海拔分布的主要优势种的研究发现,大部分主要优势种δ13C值随海拔升高而变重,但变化幅度不一致,主要因物种与小生境的不同而稍有差异。与优势种叶片δ15N相比,δ13C受海拔生境变化的影响更为明显。5、对灵石山在4个及4个以上海拔出现的优势树种叶片碳同位素与其矿质元素进行分析,300m～800 m米槠δ13C值与N、C/N间呈二次曲线相关,200m～700 m猴欢喜δ13C值与C、N、C/N、Fe和Mn之间均为二次曲线相关。在多海拔间,厚壳桂叶片δ13C值与N以及C/N之间的二次曲线极显著相关,100m～500 m罗伞树叶片δ13C值与N和Mg的二次曲线拟合效果最好,围涎树、九节木叶片δ13C值仅与少量矿质元素呈曲线相关。6、灵石山不同海拔优势树种叶片中δ15N的变动较δ13C大,不同海拔优势树种叶片δ15N的变动系数为-0.2556,其极差较大,最大值是最小值2.27倍,而优势树种叶片δ13C的变动系数为-0.0431,最大值与最小值的差异仅为15%。灵石山优势树种叶片的δ15N与δ13C不相关,优势树种叶片δ15N、δ13C与海拔的关系都呈现出二次曲线。优势树种叶片δ15N与年均温度和降水量没有表现出明显趋势,优势树种叶片δ13C随着年均温度的降低不断偏重,两者显著负相关,优势树种叶片δ13C与年均降水量表现出显著负相关。7、灵石山不同海拔表土层(0cm～20cm)土壤的δ13C均值介于-27.69‰～-20.21‰之间,平均值为-25.15‰,不同海拔表土层(0cm～20cm)土壤的δ15N均值介于-0.5‰～5.56‰之间,平均值为2.71‰,土壤δ13C和δ15N值在不同海拔梯度上的分布均存在极显著差异。土壤δ15N、δ13C之间呈显著正相关。不同土层间的δ15N、δ13C差异均不显著,土层和海拔的交互作用也不明显。土壤δ13C与土壤水分、温度之间呈现极显著正相关,土壤δ15N与土壤水分、温度之间呈现显著正相关。土壤δ15N不同海拔均值分布于-0.5‰～5.56‰,优势树种δ15N分布于-6.0405‰～0.472‰,土壤δ15N与优势树种δ15N相比显著富集。土壤δ13C分布于-25.57‰～-20.21‰,优势树种δ13C分布于-27.4265‰～-35.984‰,土壤δ13C明显较优势树种δ13C偏正,而且土壤δ13C与优势树种δ13C两者间具有显著的正相关性。更多还原

【Abstract】 In July 2012,dominant tree investigation and soil survey and sampling were conducted according to the standard of terrestrial biota observation and analysis along 9 elevations in Lingshi Mountain of soutneastern Fujian coastal zone.The foliar element contents,chlorophyll contents,leaf area δ15N and δ13C values of dominant trees and soil δ15N and δ13C values,elements and carbon flux along various elevations were determined respectively by SPAD-502,CI-203 laser leaf platometer,MAT 253 Isotope Ratio Mass Spectrometer,Flash EA1112 HT Elemental Analyzer and LI-8100 soil carbon flux admeasuring apparatus,to analyze foliar traits of dominant trees along various elevations,investigate the distribution and difference of 815N and δ13C values among dominant trees and their response to the elevation,study the effects of foliar elements on δ15N and δ13C discrimination,and reveal the correlation between foliar and soilδ15N and δ13C,between soil δ15N and δ13C and soil elements and carbon flux.The responses of foliar δ15N and δ13C traits of dominant trees and their responses to the environment were analyzed in terms of foliar and soil δ15N and δ13C and element contents in order to better understand the "environment-plant-environment" ecological mechanism and provide theoretical references for community distribution,ecosystem nutrient cycling,degraded ecosystem restoration and plant absorption of nitrogen deposition of main evergreen broad-leaf forests in mid-subtropical coastal regions.The results show that:1.The analysis of foliar element contents of dominant trees along multi elevations showed that C had highest concentration while Cu had lowest.Most elements of dominant arbor species showed insensitive responses to elevation,except Na.The elements of dominant shrub species presented various responses to the change of elevation.Based on the chlorophyll contents of dominant trees in multi elevations,there were significant differences between those of arbors and shrubs in elevations of 300 and 400 m,extremely significant differences among dominant arbors in the elevations from 300 to 700 m and among dominant shrubs in the elevations from 200 to 400 m.The leaf area of dominant trees decreased with elevations.The values of SLA of dominant arbor and shrub species were between 0.011～0.027,showing the adverse tendency with the elevations and there were significant difference between SLA values of arbor and shrub species at the same elevation.2.The foliar δ15N values of 63 samples in 26 dominant trees were from-6.0405‰ to 0.472‰,with the average of-3.1025‰.The foliar δ15N values significantly varied between different functional plants and the average δ15N value of arbors(-2.6538‰)was higher than that of shrubs(-3.3991‰).An obvious parabola curve was shown in the correlation between foliar δ15N values of dominant trees and elevations and the elevation of 400 m played an important part in foliar 815N discrimination.From the elevations of 100 m to 400 m,foliar δ15N values generally decreased with elevations while from the elevations of 400 m to 900 m,foliar δ15N values increased with elevations.Obvious variations in foliar δ15N values were shown among dominant trees in Lingshi Mountain due to species and elevations.3.In terms of the relation between foliar δ15N values and element contents of dominant trees,N and C/N of dominant arbor species had most significant effects on δ15N values,Ca and Mn had obvious correlations with δ15N values and C,K and Cu showed insignificant correlations with δ15N values.The δ15N values of dominant shrub species showed significant positive correlation with Ca,P and Mg while negative correlation with C/N.The correlation analysis of foliar δ15N values and element contents of 6 dominant arbor and shrub species at the elevations of 300 m and 400 m indicated that there were extremely significant correlations between δ15N and N,C/N,between N and C/N,between K and C,between Mg and C,Ca,between Mn and C,K and Ca,between Cu and Fe and there were significant correlations betweenδ15N and P,between Ca and C,K,between Mn and Na,Mg,between Cu and C,K,between Zn and Ca,Mg and Mn.The close correlation between δ15N and N and C/N suggested the intensive effects of N availability on foliar δ15N values in various elevations.4.The foliar δ13C values of dominant trees were from-27.4265‰ to-35.984‰,among which over 95%were from-29‰～35‰ with the average of-32.4938‰.The average δ13C value of arbors(-31.6242‰)was higher than that of shrubs(-32.5807‰).An obvious parabola curve was shown in the correlation between foliar δ13C values of dominant trees and elevations and the elevation of 300 m played an important part in foliar δ13C discrimination.From the elevations of 100 m to 300 m,foliar δ13C values generally decreased with elevations while from the elevations of 300 m to 900 m,foliar δ13C values increased with elevations.The research of dominant trees occupied multi elevations indicated that the variation range of foliar δ13C values differed with elevations,owing to the differences of species and ecological niches.Compared with δ15N,δ13C was more intensively affected by elevations.5.The dominant trees that occupied 4 or more elevations were chosen and correlation between foliarδ13C values and element contents was analyzed.Foliar δ13C values of Castanopsis carlesll had parabola correlation with N and C/N in elevations from 300 m to 800 m;foliar δ13C values of Sloanea sinensis had parabola correlation with C,N,C/N,Fe and Mn in the elevations from 200 m to 700 m;foliar δ13C values of Cryptocarya chinensis had significant parabola correlation with N and C/N in multi elevations;foliar 813C values of Ardisia quinquegona had optimal parabola fitting with N and Mg and the foliar 813C values of Irenina pithecollobii and Psychotria rubra had curvilinear correlation with only a few elements6.The amplitude of variation in foliar δ15N was greater than that in δ13C of dominant trees along various elevations in Lingshi Mountain.The variation coefficient of foliar 815N of dominant trees was-0.2556,which showed great variation amplitude.as the maximum was 2.27 times larger than the minimum.The variation coefficient of foliar 813C of dominant trees was-0.0431 and there was only difference of 15%between the maximum and minimum.The foliar δ15N and δ13C values of dominant trees were uncorrelated but they both had parabola correlation with elevation.There was no obvious correlation between foliar δ15N and AMT and AMP while a significant negative correlation was found between foliar δ13C and AMT as well as between foliar 813C and AMP.7.The soil δ13C values of 0 cm～20 cm soil layers of various elevations were from-27.69‰ to-20.21%o with the average of-25.15%o and The soil δ15N values of 0 cm～20 cm soil layers of various elevations were from-0.5‰ to 5.56‰ with the average of 2.71‰.There were highly significant differences in soilδ13C and δ15N values of various elevations,and soil 813C and 815N values were obviously positively correlated.There were insignificant differences in soil 813C and 815N values of different soil layers and obvious interaction between soil layer and elevation wasn’t found.Soil δ13C had highly significant positive correlation with soil moisture and temperature and soil δ15N had significant positive correlation with soil moisture and temperature.The soil δ15N values(-0.5‰～5.56‰)were higher than foliar δ15N values(-6.0405‰～0.472‰)in various elevations.The same trend occurred in the relation between soil δ13C values(-25.57‰～20.21‰)and foliar δ13C values(-27.4265‰～35.984‰),and a significant positive correlation was found between soil and foliar δ13C values.更多还原