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1.
《植物生态学报》2013,37(8):739
土壤养分异质性是竹林-阔叶林界面(bamboo and broad-leaved forest interface, 以下简称竹阔界面)的重要特征, 细根生长、周转和分解影响土壤养分供应能力, 但其在竹阔界面养分异质性形成中的贡献尚不清楚。该文选取竹阔界面两侧的毛竹(Phyllostachys pubescens)林和常绿阔叶林为研究对象, 开展土壤养分(C、N、P)含量、细根生物量及周转、细根分解及养分回归等指标的对比研究。结果表明: (1)竹阔界面两侧毛竹林和常绿阔叶林土壤养分差异明显, 毛竹林0-60 cm土壤有机碳(SOC)和土壤总氮(STN)含量分别为20.51和0.53 g·kg-1, 常绿阔叶林0-60 cm土壤有机碳(SOC)和土壤总氮(STN)含量分别为13.42和0.26 g·kg-1, 前者比后者分别高出34.53%和50.35%, 但毛竹林土壤全磷(STP)含量低于常绿阔叶林25.54%; (2)竹阔界面两侧细根生物量、养分密度及养分回归量差异明显, 毛竹林细根生物量高达1201.60 g·m-2, 是常绿阔叶林的5.86倍; 养分密度分别为591.42 g C·m-2、5.44 g N·m-2、0.25 g P·m-2, 分别是常绿阔叶林的6.12倍、3.77倍和3.11倍; 年均养分回归量分别为278.54 g C·m-2·a-1、2.36 g N·m-2·a-1、0.11 g P·m-2·a-1, 是常绿阔叶林的6.93倍、4.29倍和3.67倍; (3)细根对界面两侧土壤SOC、STN异质性形成的年均潜在贡献分别为76.79%和28.33%, 但对STP异质性形成起减缓作用, 贡献率为6.17%。这些结果说明毛竹扩张可以改变常绿阔叶林土壤的养分状况, 且细根对不同养分的异质性形成贡献不一致, 是土壤SOC、STN异质性形成的重要原因。  相似文献   

2.
为了弄清毛竹(Phyllostachys edulis)向针阔林扩张过程中根系的形态可塑性反应,在浙江天目山自然保护区毛竹向针阔林扩张的典型过渡地带,连续区域上设置毛竹纯林、针阔-毛竹混交林(以下简称过渡林)、针阔林3种样地。用根钻法采集样地毛竹根系、针阔树根系并比对其生物量密度、细根比根长、相邻同级侧根节点距等形态特征参数变化。结果表明:随着毛竹的扩张程度增加,林内根系生物量密度增加;且与针阔树竞争过程中毛竹将更多的根系放置于表层;同时在水平方向上随离样株距离的增加未出现明显变化,而针阔树根系则随离样木距离的增加而逐渐减少;毛竹根系比根长明显增加,平均增幅15%;一、二级侧根节点距则均有所下降,毛竹侧根数量增多。这些结果表明毛竹种群可通过根系生物量密度、细根比根长、相邻同级侧根节点距等形态可塑性方式实现向周边森林扩张。  相似文献   

3.
功能性状能够反映植物对不同环境的适应策略。毛竹扩张与外来植物入侵相似,常引起原有植物生存环境的改变,而原有植物功能性状对毛竹扩张及伐除的响应机制尚不清楚。选取毛竹-杉木混交林和去竹杉木林为研究对象,以杉木纯林为对照,比较分析杉木比叶面积、叶干物质含量、叶组织密度等叶功能性状以及比根长、细根生物量、细根根长密度等细根功能性状的变化以及其间的相关关系。结果表明:(1)与杉木纯林相比,混交林中杉木的叶相对含水量以及叶干物质含量分别减少了5.07%、0.032 g/g,叶组织密度以及比叶面积分别增加了0.005 g/cm3、10.33 cm2/g;而去竹杉木林中,杉木比叶面积、叶相对含水量减少,叶干物质含量和叶组织密度则呈上升趋势。(2)与杉木纯林相比,混交林中杉木细根生物量、细根体积密度以及细根根长密度都不断下降,而杉木细根比根长在0—20 cm土深处显著增加(P<0.05);而去竹杉木林中杉木细根比根长、细根根长密度和细根生物量则显著降低(P<0.05),细根体积密度在20—30 cm土深处有所增加。(3)杉木纯林中杉木细根功能性状间...  相似文献   

4.
毛竹扩张对常绿阔叶林土壤氮素矿化及有效性的影响   总被引:4,自引:0,他引:4  
采用时空替代法和PVC顶盖原位培养法,分析了江西大岗山毛竹扩张形成的竹-阔混交林与邻近常绿阔叶林土壤中的无机氮含量、氮矿化速率和吸收速率等指标.结果表明:两种林分土壤总无机氮含量时空变化趋势相同;竹-阔混交林年均矿化速率低于常绿阔叶林,前者以氨化作用为主,后者氨化作用与硝化作用相当,但生长季硝化作用明显占优势.两林分全年都以吸收NH4+-N为主,但生长季常绿阔叶林对NO3--N的吸收明显占优势.说明毛竹向常绿阔叶林扩张会增强土壤氮素氨化作用、减弱硝化作用和总矿化作用,同时也会增加对NH4+-N的吸收,减少对NO3--N和总无机氮的吸收.  相似文献   

5.
毛竹向周边系统扩展的能力很强,研究毛竹扩展过程中细根的适应策略,可以为毛竹林扩展调控提供科学依据。本研究以毛竹-杉木林扩展界面为对象,分析了毛竹不同扩展阶段细根生物量、根长密度、比根长及细根养分含量和比值的变化。结果表明:随着毛竹扩展,细根生物量和根长密度增加,比根长、细根N和P含量降低;与扩展前期相比,扩展后期细根生物量、根长密度分别是扩展前期的7.03、1.57倍,分别为1683.04±188.17 g·m~2和6483.14±846.82 m·m~(-3);比根长从扩展前期的2.61±0.20 m·g~(-1)降低到到扩展后期的0.70±0.06 m·g~(-1),扩展前期是扩展后期的3.73倍;细根N含量从扩展前期的5.06 g·kg~(-1)降低到扩展后期的2.98 g·kg~(-1),降低了41.11%; P含量从扩展前期的0.30 g·kg~(-1)降低到扩展后期的0.17 g·kg~(-1),降低了43.33%。相关分析表明:细根生物量、比根长与细根N、P、K、C∶N之间的相关性达到极显著水平,毛竹细根养分含量与细根形态特征协同发生了变化;毛竹向杉木林扩展时,细根形态和主要养分含量随着环境的变化发生了适应性的改变,毛竹细根具有较强的可塑性;毛竹细根在扩展前期通过增加比根长和细根N、P含量的策略,实现在新环境中的快速生长和对土壤环境的高效利用。  相似文献   

6.
毛竹具有独特的生理生态学特征,会不断地向邻近的生态系统扩张。这一现象会造成生态系统退化、土壤理化性质和微生物群落结构改变等问题,引起了人们的高度关注。然而,目前关于毛竹扩张对微生物群落结构的影响研究甚少。以安吉灵峰寺林场的长期定位试验为平台,在4条毛竹扩张样带上依次设置常绿阔叶林(BLF)、竹-阔混交林(MEF)和毛竹林(PEF)样地,测定不同林型的土壤理化性质以及微生物群落特征。结果表明: 随着毛竹的扩张,土壤pH值显著上升,毛竹林土壤pH值分别比竹-阔混交林和常绿阔叶林高0.37和0.32,而有机碳、铵态氮、硝态氮含量显著降低;除丛枝菌根真菌外,其他主要微生物类群都有下降的趋势,且微生物多样性和丰富度显著降低。毛竹扩张对土壤碳输入及养分的改变是影响地下微生物群落生物量及结构的重要因素,其中土壤有机碳、铵态氮含量是影响土壤微生物群落变化的主要因子。  相似文献   

7.
 研究了缙云山川鄂连蕊茶(Camellia rosthorniana)在3个群落类型中的生殖分配、生殖分配与个体大小之间的关系和座果率。结果表明:1)在地径1.0~3.5 cm范围内,种群间生殖分配差异显著,即毛竹林>针阔混交林>常绿阔叶林;在地径1.0~5.0 cm范围内,针阔混交林和常绿阔叶林之间差异不显著;在地径1.0~6.0 cm范围内,毛竹林显著高于针阔混交林和常绿阔叶林,而针阔混交林和常绿阔叶林之间差异不显著;因此种群间生殖分配比较时,应考虑种群间的大小分布。运用生殖分配的有关学说对川鄂连蕊茶生殖分配格局进行了解释,生境稳定性学说和生活史理论假说相结合可以解释川鄂连蕊茶生殖分配格局。2)川鄂连蕊茶个体生殖分配与个体大小之间存在抛物线关系。3)种群密度对川鄂连蕊茶座果率没有影响。  相似文献   

8.
毛竹(Phyllostachys heterocycla‘Pubescens’)凭借其独特的生长特性极易扩张进入周边的常绿或针阔混交森林群落并取而代之。菌根减弱假说对毛竹林扩张导致周边林分枯亡并抑制林下幼苗更新的机制进行了解释,即毛竹林的成功扩张是由于毛竹蔓延引起森林群落的菌根系统紊乱,使宿主植物与菌根真菌的共生关系受到干扰,进而影响了宿主植物的分布与更新。该研究以浙江省西天目山国家自然保护区为研究区域,对菌根减弱假说进行了检验。通过在毛竹-针阔混交林交接区沿毛竹扩张方向设置毛竹纯林、竹-林过渡带、针阔混交林3种类型的样带,选取在针阔混交林、竹-林过渡带同时存在的6种优势乔灌树种——杉木(Cunninghamia lanceolata)、枫香树(Liquidambar formosana)、青冈(Cyclobalanopsis glauca)、柳杉(Cryptomeria fortunei)、江浙山胡椒(Lindera chienii)、毛柄连蕊茶(Camellia fraterna),测定这6个树种在两样带中的菌根侵染频率和强度,检测在毛竹林扩张中周边森林群落菌根的响应,同时对比了毛竹在毛竹纯林和竹-林过渡带菌根感染率和强度的变化,检验该假设。实验结果表明:1)针阔混交林和竹-林过渡带的主要树种菌根都具有较高的菌根侵染频率(95%),且不同林分间林木的侵染频率无显著差异(p0.1);2)在竹-林过渡带杉木和江浙山胡椒的丛枝菌根侵染强度较针阔混交林明显增加(p0.1);3)毛竹的丛枝菌根侵染频率和强度远低于其他针阔树种,且在扩张前后没有显著变化(p0.1)。实验结果否定菌根减弱假说。  相似文献   

9.
Aims          下载免费PDF全文
 毛竹(Phyllostachys heterocycla ‘Pubescens’)凭借其独特的生长特性极易扩张进入周边的常绿或针阔混交森林群落并取而代之。菌根减弱假说对毛竹林扩张导致周边林分枯亡并抑制林下幼苗更新的机制进行了解释, 即毛竹林的成功扩张是由于毛竹蔓延引起森林群落的菌根系统紊乱, 使宿主植物与菌根真菌的共生关系受到干扰, 进而影响了宿主植物的分布与更新。该研究以浙江省西天目山国家自然保护区为研究区域, 对菌根减弱假说进行了检验。通过在毛竹-针阔混交林交接区沿毛竹扩张方向设置毛竹纯林、竹-林过渡带、针阔混交林3种类型的样带, 选取在针阔混交林、竹-林过渡带同时存在的6种优势乔灌树种——杉木(Cunninghamia lanceolata)、枫香树(Liquidambar formosana)、青冈(Cyclobalanopsis glauca)、柳杉(Cryptomeria fortunei)、江浙山胡椒(Lindera chienii)、毛柄连蕊茶(Camellia fraterna), 测定这6个树种在两样带中的菌根侵染频率和强度, 检测在毛竹林扩张中周边森林群落菌根的响应, 同时对比了毛竹在毛竹纯林和竹-林过渡带菌根感染率和强度的变化, 检验该假设。实验结果表明: 1)针阔混交林和竹-林过渡带的主要树种菌根都具有较高的菌根侵染频率(> 95%), 且不同林分间林木的侵染频率无显著差异(p > 0.1); 2)在竹-林过渡带杉木和江浙山胡椒的丛枝菌根侵染强度较针阔混交林明显增加(p < 0.1); 3)毛竹的丛枝菌根侵染频率和强度远低于其他针阔树种, 且在扩张前后没有显著变化(p > 0.1)。实验结果否定菌根减弱假说。  相似文献   

10.
缙云山川鄂连蕊茶在不同群落类型中的RAPD分析   总被引:7,自引:2,他引:5  
操国兴  钟章成  谢德体  刘芸  龙云 《生态学报》2003,23(8):1583-1589
采用随机扩增多态性DNA(RAPD)对常绿阔叶林灌木层广布种川鄂连蕊茶(Camellia rosthorniana)在缙云山3个群落类型(毛竹林、针阔混交林和常绿阔叶林)中的遗传结构和DNA多样性进行了研究。10个引物共扩增出138个产物,其中115个是多态性的,多态位点比率为83.33%。Shannon指数估算的3个种群的遗传多样性为常绿阔叶林0.3345,毛竹林0.3148,针阔混交林0.3085,遗传分化为8.12%;Nei指数计算的3个种群的基因多样性为常绿阔叶林0.2095,毛竹林0.1981,针阔混交林0.1934,遗传分化为7.51%。种群间遗传距离在0.0177~0.0393之间。川鄂连蕊茶在3个群落中的种群大小和生长状况不同,各种群遗传多样性的高低可能是对所处群落生境的适应。  相似文献   

11.
Fine root turnover is a major pathway for carbon and nutrient cycling in terrestrial ecosystems and is most likely sensitive to many global change factors. Despite the importance of fine root turnover in plant C allocation and nutrient cycling dynamics and the tremendous research efforts in the past, our understanding of it remains limited. This is because the dynamics processes associated with soil resources availability are still poorly understood. Soil moisture, temperature, and available nitrogen are the most important soil characteristics that impact fine root growth and mortality at both the individual root branch and at the ecosystem level. In temperate forest ecosystems, seasonal changes of soil resource availability will alter the pattern of carbon allocation to belowground. Therefore, fine root biomass, root length density (RLD) and specific root length (SRL) vary during the growing season. Studying seasonal changes of fine root biomass, RLD, and SRL associated with soil resource availability will help us understand the mechanistic controls of carbon to fine root longevity and turnover. The objective of this study was to understand whether seasonal variations of fine root biomass, RLD and SRL were associated with soil resource availability, such as moisture, temperature, and nitrogen, and to understand how these soil components impact fine root dynamics in Larix gmelinii plantation. We used a soil coring method to obtain fine root samples (⩽2 mm in diameter) every month from May to October in 2002 from a 17-year-old L. gmelinii plantation in Maoershan Experiment Station, Northeast Forestry University, China. Seventy-two soil cores (inside diameter 60 mm; depth intervals: 0–10 cm, 10–20 cm, 20–30 cm) were sampled randomly from three replicates 25 m × 30 m plots to estimate fine root biomass (live and dead), and calculate RLD and SRL. Soil moisture, temperature, and nitrogen (ammonia and nitrates) at three depth intervals were also analyzed in these plots. Results showed that the average standing fine root biomass (live and dead) was 189.1 g·m−2·a−1, 50% (95.4 g·m−2·a−1) in the surface soil layer (0–10 cm), 33% (61.5 g·m−2·a−1), 17% (32.2 g·m−2·a−1) in the middle (10–20 cm) and deep layer (20–30cm), respectively. Live and dead fine root biomass was the highest from May to July and in September, but lower in August and October. The live fine root biomass decreased and dead biomass increased during the growing season. Mean RLD (7,411.56 m·m−3·a−1) and SRL (10.83 m·g−1·a−1) in the surface layer were higher than RLD (1 474.68 m·m−3·a−1) and SRL (8.56 m·g−1·a−1) in the deep soil layer. RLD and SRL in May were the highest (10 621.45 m·m−3 and 14.83m·g−1) compared with those in the other months, and RLD was the lowest in September (2 198.20 m·m−3) and SRL in October (3.77 m·g−1). Seasonal dynamics of fine root biomass, RLD, and SRL showed a close relationship with changes in soil moisture, temperature, and nitrogen availability. To a lesser extent, the temperature could be determined by regression analysis. Fine roots in the upper soil layer have a function of absorbing moisture and nutrients, while the main function of deeper soil may be moisture uptake rather than nutrient acquisition. Therefore, carbon allocation to roots in the upper soil layer and deeper soil layer was different. Multiple regression analysis showed that variation in soil resource availability could explain 71–73% of the seasonal variation of RLD and SRL and 58% of the variation in fine root biomass. These results suggested a greater metabolic activity of fine roots living in soil with higher resource availability, which resulted in an increased allocation of carbohydrate to these roots, but a lower allocation of carbohydrate to those in soil with lower resource availability. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(3): 403–410 [译自: 植物生态学报, 2005, 29(3): 403–410]  相似文献   

12.
浙江西天目山主要森林类型的苔藓多样性比较   总被引:1,自引:0,他引:1       下载免费PDF全文
 苔藓是森林的重要组分, 是森林保护区的重要保护对象, 在物种资源和生态系统功能维护中有重要作用。该研究以浙江西天目山国家自然保护区内7种主要森林类型(落叶矮林、落叶阔叶林、常绿-落叶阔叶混交林、常绿阔叶林、针阔混交林、针叶林和竹林)内的苔藓植物为对象, 调查了32个10 m × 10 m的样地, 记录地面生苔藓植物盖度和树附生苔藓植物多度, 采用重要值、相似性系数、多样性指数分析了森林类型间的苔藓植物多样性差异。共采集969份标本, 隶属41科84属142种, 其中苔类植物13科18属33种, 藓类植物28科66属109种, 优势科为灰藓科、青藓科和羽藓科。2种混交林(常绿-落叶阔叶混交林和针阔混交林)的物种丰富度和多样性指数均高于其余5种森林, 其中物种丰富度以针阔混交林最高, 苔藓植物多样性则以常绿-落叶阔叶混交林最高, 竹林两者均为最低。海拔等环境因子较为接近的植被类型的苔藓植物多样性相似性较高, 常绿阔叶林与针叶林相似性最高, 而落叶矮林和竹林相似性最小。  相似文献   

13.
以4种不同生活型树种(常绿阔叶和针叶树种、落叶阔叶和针叶树种)为研究对象,通过微根管法现地观测细根的生长动态,比较不同生活型树种细根寿命在种内和种间的差异,探讨影响细根寿命的主要因子,研究结果对理解和预测森林生态系统碳及养分循环过程具有重要的理论意义。结果表明:(1)细根形态特征(分枝结构和直径)显著影响种内细根寿命,分枝等级越低、直径越小,细根的寿命越短;(2)4个树种的细根寿命表现出明显的土层效应和季节效应,即随土壤深度增加,细根的累积存活率逐渐增加,寿命延长;而不同季节出生的细根其寿命长短模式在树种间不一致,春季或夏季出生的细根寿命要长于秋冬季;(3)常绿树种(柳杉、石栎)的细根寿命要长于落叶树种(池杉、麻栎),同时,针叶树种(池杉、柳杉)的细根寿命要长于阔叶树种(麻栎、石栎)。在同一树种内,细根寿命受细根直径、根系分枝结构、土壤环境因子(土层)等因素显著影响,但在不同树种间,细根寿命可能更依赖于树木生长速率、碳分配模式等树木整体的功能性状差异。  相似文献   

14.
落叶松人工林细根动态与土壤资源有效性关系研究   总被引:39,自引:4,他引:35       下载免费PDF全文
 树木细根在森林生态系统C和养分循环中具有重要的作用。由于温带土壤资源有效性具有明显的季节变化,导致细根生物量、根长密度(Root length density, RLD)和比根长(Specific root length, SRL)的季节性变化。以17年生落叶松(Larix gmelini)人工林为研究对象,采用根钻法从5月到10月连续取样,研究了不同土层细根(直径≤2 mm)生物量、RLD和SRL的季节动态,以及这些根系指标动态与土壤水分、温度和N有效性的关系。结果表明:1) 落叶松细根年平均生物量(活根+死根)为189.1 g·m-2·a-1,其中50%分布在表层(0~10 cm),33%分布在亚表层(11~20 cm),17%分布在底层(21~30 cm)。活根和死根生物量在5~7月以及9月较高,8月和10月较低。从春季(5月)到秋季(10月),随着活细根生物量的减少,死细根生物量增加;2)土壤表层(0~10 cm)具有较高的RLD和SRL,而底层(21~30 cm)最低。春季(5月)总RLD和SRL最高,分别为10 621.45 m·m-3和14.83 m·g-1,到秋季(9月)树木生长结束后达到最低值,分别为2 198.20 m·m-3和3.77 m·g-1;3)细根生物量、RLD和SRL与土壤水分、温度和有效N存在不同程度的相关性。从单因子分析来看,土壤水分和有效N对细根的影响明显大于温度,对活根的影响大于死根。由于土壤资源有效性的季节变化,使得C的地下分配格局发生改变。各土层细根与有效性资源之间的相关性反映了细根功能季节性差异。细根 (生物量、RLD和SRL) 的季节动态(58%~73%的变异)主要由土壤资源有效性的季节变化引起。  相似文献   

15.
Very fine roots (<0.5 mm in diameter) of forest trees may serve as better indicators of root function than the traditional category of <2 mm, but how these roots will exhibit the plasticity of species-specific traits in response to heterogeneous soil nutrients is unknown. Here, we examined the vertical distribution of biomass and morphological and physiological traits of fine roots across three narrow diameter classes (<0.5, 0.5–1.0, and 1.0–2.0 mm) of Quercus serrata and Ilex pedunculosa at five soil depths down to 50 cm in a broad-leaved temperate forest. In both species, biomass and the allocation of very fine roots were higher in the surface soil but lower below 10-cm soil depth compared to values for larger roots (0.5–2.0 mm). When we applied these diameter classes, only very fine roots of Q. serrata exhibited significant changes in specific root length (SRL; m g−1) and root nitrogen (N) concentrations with soil depth, whereas the N concentrations only changed significantly in I. pedunculosa. The SRL and root N concentrations of larger roots in the two species did not significantly differ among soil depths. Thus, very fine roots may exhibit species-specific traits and change their potential for nutrient and water uptake in response to soil depth by plasticity in root biomass, the length, and the N in response to available resources.  相似文献   

16.
Fine root tumover is a major pathway for carbon and nutrient cycling in terrestrial ecosystems and is most likely sensitive to many global change factors.Despite the importance of fine root turnover in plant C allocation and nutrient cycling dynamics and the tremendous research efforts in the past,our understanding of it remains limited.This is because the dynamics processes associated with soil resources availability are still poorly understood.Soil moisture,temperature,and available nitrogen are the most important soil characteristics that impact fine root growth and mortality at both the individual root branch and at the ecosystem level.In temperate forest ecosystems,seasonal changes of soil resource availability will alter the pattern of carbon allocation to belowground.Therefore,fine root biomass,root length density(RLD)and specific root length(SRL)vary during the growing season.Studying seasonal changes of fine root biomass,RLD,and SRL associated with soil resource availability will help us understand the mechanistic controls of carbon to fine root longevity and turnover.The objective of this study was to understand whether seasonal variations of fine root biomass,RLD and SRL were associated with soil resource availability,such as moisture,temperature,and nitrogen,and to understand how these soil components impact fine root dynamics in Larix gmelinii plantation.We used a soil coring method to obtain fine root samples(≤2 mm in diameter)every month from Mav to October in 2002 from a 17-year-old L.gmelinii plantation in Maoershan Experiment Station,Northeast Forestry University,China.Seventy-two soil cores(inside diameter 60 mm;depth intervals:0-10 cm,10-20 cm,20-30 cm)were sampled randomly from three replicates 25 m×30 m plots to estimate fine root biomass(live and dead),and calculate RLD and SRL.Soil moisture,temperature,and nitrogen(ammonia and nitrates)at three depth intervals were also analyzed in these plots.Results showed that the average standing fine root biomass(live (32.2 g.m-2.a-1)in the middle(10-20 cm)and deep layer (20-30cm),respectively.Live and dead fine root biomass was the highest from May to July and in September,but lower in August and October.The live fine root biomass decreased and dead biomass increased during the growing soil layer.RLD and SRL in May were the highestthe other months,and RLD was the lowest in Septemberdynamics of fine root biomass,RLD,and SRL showed a close relationship with changes in soil moisture,temperature,and nitrogen availability.To a lesser extent,the temperature could be determined by regression analysis.Fine roots in the upper soil layer have a function of absorbing moisture and nutrients,while the main function of deeper soil may be moisture uptake rather than nutrient acquisition.Therefore,carbon allocation to roots in the upper soil layer and deeper soil layer was different.Multiple regression analysis showed that variation in soil resource availability could explain 71-73% of the seasonal variation of RLD and SRL and 58% of the variation in fine root biomass.These results suggested a greater metabolic activity of fine roots living in soil with higher resource availability,which resulted in an increased allocation of carbohydrate to these roots,but a lower allocation of carbohydrate to those in soil with lower resource availability.  相似文献   

17.
武夷山落叶林木本植物细根性状研究   总被引:3,自引:1,他引:2       下载免费PDF全文
王钊颖  程林  王满堂  孙俊  钟全林  李曼  程栋梁 《生态学报》2018,38(22):8088-8097
细根作为植物吸收水分与养分的重要器官,其性状特征在指示植物的生长和分布等方面的意义重大。以江西武夷山国家级自然保护区落叶林群落木本植物的细根为对象,对根氮含量(RNC)、根磷含量(RPC)、根氮磷比(RN∶P)、根组织密度(RTD)、比根长(SRL)和比根面积(SRA)等6个细根性状进行了研究,并对群落内不同物种以及不同结构单元(灌木和乔木)间细根性状的差异性进行分析。结果表明:武夷山落叶林群落木本植物的平均RNC为(10.27±3.11) mg/g、平均RPC为(0.63±0.17) mg/g、平均RN∶P为16. 36±2. 61、平均RTD为(0. 10±0. 02) g/cm~3、平均SRL为(1582.65±186.67) cm/g、平均SRA为(464.81±64.10) cm~2/g;灌木的SRL显著高于乔木(P=0.033),其余细根性状在灌木和乔木之间无显著差异(P 0.05);在细根性状中,RNC与RPC呈极显著正相关,但与RTD呈显著负相关,RPC、SRA分别与RTD呈极显著负相关,RPC、SRL分别与SRA呈极显著正相关。这可能反映了灌木倾向于通过增加SRL来提高水分和养分的获取能力以增强与乔木的竞争优势;群落中的植物通过改变SRA及RTD进行生长与防御之间的权衡。  相似文献   

18.
细根直径变异是根系形态变化的常见形式, 对细根变异研究具有重要意义。为了揭示亚热带天然常绿阔叶林一级根直径变异特征, 该研究选取福建省建瓯市万木林自然保护区天然常绿阔叶林的89种木本植物进行研究。每个树种选取胸径或地径相近的3株, 用完整土块法进行根系取样, 用根序法对根系进行分级。采用单因素方差分析分别检验叶片习性(常绿、落叶树种)、生长型(乔木、小乔木或灌木、灌木)和主要科之间一级根直径的差异; 通过计算Blomberg’s K值以检验系统发育信号; 利用线性回归方法, 分析科水平的分化时间与一级根直径的相关性。结果显示: 1)亚热带常绿阔叶林一级根直径变异系数为23%; 2)常绿树种与落叶树种一级根直径没有显著差异, 但灌木一级根直径显著小于小乔木或灌木、乔木; 3)一级根直径系统发育信号不显著, 科水平分化时间与一级根直径呈正相关关系。研究结果表明, 亚热带天然常绿阔叶林木本植物一级根直径变异受系统发育影响较小, 但受生长型影响, 表现为一定的趋同适应。  相似文献   

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