武夷山低海拔和高海拔森林土壤有机碳的矿化特征

研究不同海拔土壤有机碳矿化对深入认识不同海拔森林土壤有机碳动态变化具有重要意义.本文以武夷山低海拔和高海拔森林土壤为研究对象,通过室内模拟其在各自年平均气温(17、9℃)条件下的矿化培养试验,探讨土壤有机碳矿化特征的差异.结果表明:培养126 d后,尽管高海拔森林土壤的有机碳含量显著高于低海拔森林土壤,但低海拔和高海拔森林土壤在各自环境温度背景下的有机碳累积矿化量并无显著差异.一级动力学方程均能较好地模拟高低海拔森林土壤有机碳矿化特征,高海拔和低海拔森林土壤有机碳潜在矿化量(CP)和矿化速率常数均无显著差异,但低海拔土壤C_P/SOC值和矿化率显著高于高海拔土壤,表明在环境温度背景下,低海拔土壤固碳能力低于高海拔土壤.随着培养时间增加,高海拔土壤微生物生物量碳和微生物熵显著高于低海拔土壤,表明高海拔土壤微生物的碳同化量高于低海拔土壤微生物,有利于有机碳的积累.高海拔森林土壤中的β-葡萄糖甘酶和纤维素水解酶高于低海拔森林土壤,说明高海拔土壤微生物可能更多地分解活性碳.未来气候变暖可能暗示着会降低高海拔土壤有机碳固碳能力和微生物碳利用效率,从而导致土壤有机碳储量下降.     

贺兰山东坡不同海拔梯度土壤酶化学计量特征

土壤胞外酶是生物地球化学循环的主要参与者，与微生物的代谢需求和养分供应密切相关。然而，对干旱区山地生态系统沿海拔梯度土壤微生物养分限制状况及其驱动因素尚不清楚。基于此，以贺兰山海拔1300-2700m范围内7个海拔梯度的土壤为研究对象，揭示贺兰山土壤理化性质、胞外酶活性及微生物养分限制的海拔分布格局，分析影响微生物养分限制的驱动因素。结果表明：随着海拔梯度的升高，土壤含水率（SWC）和有机碳（SOC）含量逐渐增加，容重（BD）和pH整体呈现逐渐降低的趋势。海拔显著影响土壤胞外酶活性，五种参与土壤碳（C）、氮（N）、磷（P）循环的酶活性随着海拔的升高整体呈现逐渐上升的变化趋势，总体表现出中低海拔酶活性较低，高海拔酶活性较高。胞外酶矢量分析显示，矢量长度在中低海拔处较高，而矢量角度则在高海拔处较高，表明贺兰山土壤微生物在中低海拔和高海拔分别具有相对较强的C和P限制。土壤含水率、容重、C、N、P含量与土壤胞外酶活性及其化学计量比显著相关，是调控土壤胞外酶活性随海拔变化的主要因子，说明胞外酶在旱区山地生态系统土壤物质循环过程中具有重要的作用。该研究结果对揭示土壤微生物和胞外酶之间养分元素循环的耦合机理，为深入探讨贺兰山森林生态系统物质循环和不同海拔梯度植被有效管理提供科学依据。     

Microbial communities and activities in alpine and subalpine soils

Soil samples were collected along two slopes (south and north) at subalpine (1500–1900 m, under closed vegetation, up to the forest line) and alpine altitudes (2300–2530, under scattered vegetation, above the forest line) in the Grossglockner mountain area (Austrian central Alps). Soils were analyzed for a number of properties, including physical and chemical soil properties, microbial activity and microbial communities that were investigated using culture-dependent (viable heterotrophic bacteria) and culture-independent methods (phospholipid fatty acid analysis, FISH). Alpine soils were characterized by significantly ( P <0.01) colder climate conditions, i.e. lower mean annual air and soil temperatures, more frost and ice days and higher precipitation, compared with subalpine soils. Microbial activity (soil dehydrogenase activity) decreased with altitude; however, dehydrogenase activity was better adapted to cold in alpine soils compared with subalpine soils, as shown by the lower apparent optimum temperature for activity (30 vs. 37 °C) and the significantly ( P <0.01–0.001) higher relative activity in the low-temperature range. With increasing altitude, i.e. in alpine soils, a significant ( P <0.05–0.01) increase in the relative amount of culturable psychrophilic heterotrophic bacteria, in the relative amount of the fungal population and in the relative amount of Gram-negative bacteria was found, which indicates shifts in microbial community composition with altitude.     

Soil nitrogen mineralization rates of rainforests in a matrix of elevations and geological substrates on Mount Kinabalu, Borneo

Mt Kinabalu, Borneo, is characterized by a deep elevational gradient and mosaics of geological substrates. We chose a pair of two geological substrates (sedimentary vs ultrabasic) at five altitudes (800, 1400, 2100, 2700 and 3100 m a.s.l.). We investigated soil nitrogen (N) mineralization and nitrification rates using an incubation technique to assay the pattern and control of soil N status in this environmental matrix. In situ net mineralization rates decreased with elevation on both substrates. The decreasing pattern was linear across altitudes on ultrabasic rock, whereas on sedimentary rock it was depressed in the middle slope wet cloud zone. Sedimentary sites in this zone had low soil redox potential values and this anoxic soil condition might be related to slow N mineralization. The in situ rates were significantly greater (P < 0.05, anova) on sedimentary than on ultrabasic rock at the same altitudes except in the cloud zone. Net mineralization rates of the soils that were collected from different elevations and incubated in the same conditions were statistically invariable (P > 0.05) among the original elevations for sedimentary rock, but were variable (P < 0.05) for ultrabasic rock. Those of the soils that were collected from the same elevation and incubated at different elevations decreased significantly across altitudes (P < 0.05) for sedimentary rock, while they were invariable (P > 0.05) for ultrabasic rock. Thus, temperature had stronger effects on net N mineralization on sedimentary rock, whereas inherent soil quality had stronger effects on ultrabasic rock. Controls of soil N mineralization might be different between the two substrates, leading to diverse biogeochemical site conditions on Kinabalu.     

亚热带不同海拔黄山松林土壤磷组分及微生物特征

磷是亚热带地区植物生长必需的养分元素之一,海拔梯度可能会改变土壤-植物-微生物系统并影响土壤磷形态及有效性。了解不同海拔土壤磷组分状况,对维持山地森林生态系统可持续发展具有重要的意义。以戴云山地区不同海拔梯度(1300m和1600 m)黄山松林为研究对象,分析了土壤磷组分、微生物群落特征和磷酸酶活性。结果显示:海拔显著影响黄山松林土壤磷组分,与海拔1300 m相比,海拔1600 m处土壤总磷含量减少了48.4%—49.8%,且各磷组分(易分解态磷、中等易分解态磷和难分解态磷)含量也显著降低,淋溶层(A层)土壤的降低程度分别为45.7%、58.6%和38.7%,淀积层(B层)为82.6%、59.9%和31.1%。海拔对土壤微生物群落特征和酶活性亦有显著影响,各类微生物群落和总微生物磷脂脂肪酸含量(PLFAs),以及磷酸双酯酶(PD)活性均表现为海拔1600 m 1300 m,但酸性磷酸单酯酶(ACP)活性呈相反的趋势。冗余分析(RDA)表明,土壤磷组分主要受有机碳(SOC)调控,且SOC与有机磷组分(Na HCO3-Po和Na OH-Po)呈显著正相关;磷酸酶和外生菌根真菌(EMF)也是影响土壤磷组分变化的重要因素。研究表明,土壤有机质含量和微生物群落结构及功能的变化可能是不同海拔黄山松林土壤磷有效性的关键调控因素。     

Vertical distribution and pools of microbial residues in tropical forest soils formed from distinct parent materials

The contribution of soil microbial residues to stable carbon pools may be of particular importance in the tropics where carbon residence times are short and any available carbon is rapidly utilized. In this study we investigated the vertical distribution of microbially-derived amino sugars in two tropical forests on contrasting meta-sedimentary and serpentinite parent materials in the lowlands of Mt. Kinabalu, Borneo. Despite their similar climate, vegetative cover, and general microbial community structure, the two soils were chemically and physically distinct. We found that both parent material and depth significantly influenced the pool sizes of microbial residues in the two soils. In particular, the soil derived from sedimentary parent material had greater amino sugar contents, glucosamine to galactosamine ratios, and percentage of total soil carbon that is amino sugar derived, than the soil derived from serpentinite substrate. We speculate that residue stabilization was linked to soil iron oxide content, with significant difference in amino sugars contribution to total soil carbon at depth in the serpentinite-derived soil versus that derived from sedimentary parent material. Based on observed patterns of amino sugar content and relative abundance we suggest that near the surface of both soils vegetation and litter input determines the composition and quantity of microbial residues. With increasing depth the influence of vegetation declines and production and stabilization of microbial amino sugars becomes driven by soil matrix characteristics. These differences in stabilization mechanism and carbon dynamics with depth may be particularly critical in deep weathered tropical soils.     

Soil phosphorus fractionation and phosphorus-use efficiencies of tropical rainforests along altitudinal gradients of Mount Kinabalu, Borneo

We studied soil phosphorus (P) fractionation and P-use efficiencies (PUEs) of rainforests along altitudinal gradients (700–3100 m) on two types of parental rocks (sedimentary versus ultrabasic) on Mount Kinabalu, Borneo. Sedimentary rocks were known to contain more quartz (which does not adsorb P) than ultrabasic rocks. The pool (top 30 cm) of total P was always greater on sedimentary (ranging from 34.9 to 72.6 g m^–2) than on ultrabasic (9.0–29.2 g m^–2) rocks at comparable altitudes. Accordingly, the pools of organic P and labile inorganic P were always greater on sedimentary than on ultrabasic rocks. The pool of primary mineral, calcium P increased upslope from 1.7 to 4.3 g m^–2 on sedimentary rock, suggesting that the altitudinal sequence of the sites reflected a decreasing magnitude of soil weathering upslope. The pool of calcium P on ultrabasic rock did not vary consistently with altitude (1.2–2.8 g m^–2), probably reflecting the greater between-site variability of primary mineral P in parent rocks. When all sites were compared, the pool of most labile, bicarbonate-extracted inorganic P increased (ranging from 0.02 to 1.85 g m^–2) with increasing calcium P. Calcium P was therefore considered to be an important P source to the biota on Kinabalu. Gross patterns in the variation of PUE (indexed as the reciprocal of the P concentration in litter) were best explained by the pool size of actively cycling P (total P minus occluded inorganic P). PUE, however, demonstrated distinct altitudinal patterns to generate an intricate conrol of P use pattern by soil P pools and altitude. Received: 2 August 1998 / Accepted: 28 November 1999     

广西猫儿山不同海拔土壤碳氮磷生态化学计量特征

为探究我国华南地区山地土壤有机碳(C)、氮(N)、磷(P)含量垂直分布特征,阐明土壤C、N、P生态化学计量特征对海拔和土层深度的响应,以广西猫儿山为研究对象,选取不同海拔的10个地点,采集了不同发生层的土壤,测定有机C、N、P、pH、容重和机械组成等土壤性质,探讨了不同海拔及深度土壤C、N、P生态化学计量特征及其影响因素.结果表明: 随着海拔升高,土壤C、N、C/P、N/P均呈增加趋势,土壤P呈先增后降趋势,C/N则呈先增后保持平稳趋势;随着土壤深度增加,土壤C、N、P、C/P、N/P均呈显著降低趋势,C/N无显著变化,C、N在不同发生层土壤间具有较高的耦合性(C/N变异系数为4.0%);土壤P在空间上的变异较小(不同海拔、发生层间变异系数分别为31.0%和22.0%).冗余分析结果显示,前2个排序轴反映了土壤C、N、P化学计量特征变异信息量的74.8%,土壤pH、容重和海拔对土壤C、N、P化学计量特征有显著影响,而黏粒、粉粒和砂粒影响效果不显著.     

Ecosystem Restoration of Jhum Fallows in Northeast India: Microbial C and N Along Altitudinal and Successional Gradients

Abstract To characterize the altitudinal and successional trends in microbial biomass and to understand their role in soil nutrient dynamics during the aggradation phase (vegetation recovery) of abandoned shifting cultivation systems, we determined the soil properties and microbial C and N in jhum (slash‐and‐burn) cultivation systems at different altitudes and 1‐, 7‐, and 16‐year‐old fallow agricultural lands at lower and higher altitudes in the northeastern Indian hills. Density of ground vegetation was lower in the undisturbed forest than in the jhum fallows. In general, 1‐year jhum fallow had greater herbaceous vegetation both at lower and higher altitudes. Although woody plants were observed in 7‐ and 16‐year‐old jhum fallows, their density was highest in the forest. Soil moisture, organic C, and total N also increased gradually with increasing altitude and progressive secondary succession. Soil pH showed a negative correlation with altitude (as also confounded by soil type) and fallow age. Both microbial C and N had a close correlation with altitude and fallow age. Contribution of microbial C to soil organic C was 2.0–2.6% and microbial N to total N 1.4–2.2% in jhum fields, 2.4–4.3% and 1.2–2.1%, respectively, in jhum fallows, and 2.5–2.9% and 1.6–1.9% in the forests. Microbial C and N showed a negative correlation with herbaceous plant density. Microbial biomass in the jhum fallows and forest stands had a positive relationship with woody vegetation. Along an altitudinal and/or successional gradient, microbial C and N were positively correlated with water‐holding capacity, soil moisture, organic C, and total N and negatively correlated with soil pH. Microbial C and N were positively correlated with each other. Therefore, the study suggests that the altitudinal and successional dynamics of microbial C and N are linked to, among other properties, soil organic matter and total nitrogen contents in the soil during community development after land abandonment from shifting cultivation.     

猫儿山不同海拔植被带土壤微生物群落功能多样性

为研究中亚热带森林土壤微生物群落功能多样性特征及其随海拔梯度的变化,应用Biolog微平板技术,对猫儿山不同海拔植被带(常绿阔叶林(EBF)、落叶阔叶混交林(DBF)、针阔混交林(CBF))土壤微生物群落功能多样性差异进行了比较。结果表明,不同海拔植被带土壤微生物群落功能多样性差异显著。土壤平均颜色变化率(AWCD)随培养时间延长而逐渐增加,随着海拔升高,土壤AWCD值逐渐降低,大小顺序为EBFDBFCBF。土壤微生物群落Shannon指数和丰富度指数的总体趋势为EBF最高,DBF次之,CBF最低。不同海拔植被带土壤微生物群落均匀度指数之间差异不显著。不同海拔植被带土壤微生物对不同碳源的利用能力存在差异,其中EBF利用率最高,CBF利用率最低,氨基酸类、胺类和酯类碳源为各海拔植被带土壤微生物利用的主要碳源。主成分分析结果表明,主成分1和主成分2分别能解释变量方差的40.42%和15.97%,在主成分分离中起主要贡献作用的是酯类、胺类和氨基酸类碳源。土壤理化性质与土壤微生物群落功能多样性之间的相关性分析结果表明,微生物群落多样性的Shannon指数与全钾(TK)呈极显著正相关(P0.01),与含水量呈极显著负相关(P0.01),与总有机碳(TOC)、全氮(TN)、速效氮(AN)、有效P(AP)之间的相关性显著(P0.05)或极显著(P0.01),且为负相关。土壤TK含量和含水量可能是造成不同海拔土壤微生物群落功能多样性差异的主要原因。     

秦岭火地塘真菌群落海拔分布格局

土壤真菌在自然生态系统的养分循环和土壤碳储存方面起重要作用。秦岭火地塘林区在不同海拔分布着不同的优势树种,但其相应的土壤特征及微生物群落的海拔分布格局仍不明晰。本研究分析了5个海拔处(1500、1700、1900、2100和2300 m)的土壤特征变化趋势,并在高通量测序基础上研究了真菌群落格局。结果表明: 土壤有效磷含量、pH值随海拔的增加而显著增加,土壤水分则呈下降趋势。土壤真菌Shannon多样性指数随海拔升高呈下降趋势,而ACE丰度指数相反;真菌优势门为担子菌门(68.2%)、子囊菌门(19.8%)和球囊菌门(1.7%),且随海拔升高整体呈现出“U”型或“单峰”变化格局;真菌优势纲为伞菌纲(64.2%)、粪壳菌纲(5.8%)和锤舌菌纲(4.1%)。冗余分析(RDA)表明,土壤特性解释了土壤真菌群落总变异的89.1%,其中土壤有效磷含量、pH和海拔是土壤真菌群落海拔梯度变化的主要驱动因子。在秦岭火地塘林区,土壤特征在海拔梯度上的差异性影响了土壤真菌群落组成。     

贺兰山不同海拔植被下土壤微生物群落结构特征

为明确海拔变化对干旱区山地森林土壤微生物群落的影响,揭示环境因子改变后土壤微生物群落结构特征及影响因素。对贺兰山5个海拔梯度土壤理化性质进行测定,同时采用磷酸脂肪酸(PLFA)图谱法分析土壤微生物群落组成,通过主成分分析、冗余分析(RDA)探究土壤理化性质与土壤微生物群落相对丰度之间的相关关系。结果表明:土壤养分含量在不同海拔之间差异性显著(P<0.05),土壤有机碳和全氮含量随海拔的升高而升高,全磷含量随海拔升高先升高再降低再升高;土壤微生物量随海拔升高先升高后降低,土壤微生物的相对丰度在不同海拔之间存在差异(P<0.05);主成分分析表明,与第1主成分相关性较强的微生物类群为革兰氏阳性细菌(G~+)、革兰氏阴性细菌(G~-)和真菌;与第2主成分相关性较强的微生物类群为放线菌、原生动物和非特异性细菌。非特异性细菌和真菌与各土壤因子之间均有显著相关关系,而放线菌、G~+和G~-与各土壤因子相关性较弱,原生动物与土壤全磷含量的关系密切。海拔是影响特征微生物分布的重要因素,特征微生物的含量和相对丰度随海拔的升高先升高后降低,符合山地生态学中的"中部膨胀"理论。探明了贺兰山不同海...     

西藏色季拉山垂直植被带土壤细菌群落组成及功能潜势

研究青藏高原土壤微生物群落组成和功能的空间分布特征有助于深入理解典型高寒生态系统中土壤微生物的重要生态功能。本研究采用16S rDNA高通量测序方法,分析了西藏色季拉山4个不同海拔土壤细菌群落物种组成和功能潜势的变化特征及其驱动因子。结果表明: 随着海拔的升高,土壤细菌的丰富度和Shannon多样性指数显著降低;酸杆菌门、绿弯菌门、芽单胞菌门和硝化螺旋菌门的相对丰度显著增加,而变形菌门、放线菌门和拟杆菌门的相对丰度则显著降低。KEGG二级代谢通路中,膜运输及氨基酸、脂类、萜类和聚酮类化合物代谢相关基因的相对丰度在高海拔显著降低,而碳水化合物代谢、信号转导、复制与修复、酶家族等基因丰度则显著升高。不同海拔土壤细菌群落组成和功能潜势的变化受到植被和土壤因子的显著影响,并且pH值是关键驱动因子。群落功能潜势与放线菌门、拟杆菌门、纤维杆菌门等种群丰度显著相关。不同海拔下群落KEGG代谢通路基因组成的差异(β多样性)与土壤细菌群落结构的差异呈显著正相关,说明微生物群落组成与功能潜势之间可能存在紧密关联。     

武夷山不同海拔高度土壤活性有机碳变化

采用连续熏蒸 培养法,测定了福建武夷山自然保护区不同海拔高度具有代表性的中亚热带常绿阔叶林、针叶林、亚高山矮林以及高山草甸土壤中有效碳含量,分析了土壤有效碳（LOC）与微生物量碳（MBC）、土壤总有机碳（TOC）、细根生物量（FRB）和土壤全氮（TN）之间的关系.结果表明：土壤有效碳占总有机碳的3.40%～7.46%;微生物量碳只是土壤有效碳中的一部分,占土壤有效碳26.87%～80.38%; 不同林分土壤有效碳含量随海拔增高而显著增大,随土层深度的增加而降低;土壤有效碳与微生物量碳、土壤总有机碳、细根生物量、土壤全氮之间呈极显著的相关关系.高海拔土壤有效碳含量显著高于低海拔土壤.     

Soil humic compounds and microbial communities in six spruce forests as function of parent material, slope aspect and stand age

The influences on soil chemical and microbial properties of parent material, north south aspect and time measured as stand age were investigated in six spruce (Picea abies (L.) Karst.) forests located in the alpine range of Northern Italy. Soil samples from A horizons were analysed for humic substances and in parallel Amplified Ribosomal DNA Restriction Analysis (ARDRA) community profiles and microbial biomass carbon and nitrogen content were determined. Chemical data were analyzed by canonical discriminant analysis while the ARDRA fingerprints were ordered in clusters using image analysis software. The geologic parent material was the most determining factor and the aspect-dependent microclimate features also played a distinct role in defining both soil chemistry and microbial community composition; in contrast the composition of the deeper humus layers (OH, A) was stable and similar within a spruce forest cycle time. Most important variables in the construction of the discriminating models resulted soil pH, Dissolved Organic Carbon content and Dissolved Organic Matter phenolic compounds. Bacterial communities appeared to be shaped first and foremost by the substratum, secondly by mountain slope orientation, and thirdly by forest stage, thus confirming the CDA model.     

Soil-derived organic particles and their effects on the community of culturable microorganisms

Soil microbial community interacts with a range of particulate material in the soil, consisting of both inorganic and organic compounds with different levels of water solubility. Though sparingly water-soluble and insoluble organic compounds in the soil may affect living organisms, they are difficult to introduce into microbiological media. Their biological activity (i.e., their effect on soil microorganisms) thus has been almost neglected in most of the cultivation assays. To fill this gap, we propose the use of fine organic particles prepared from soil organic matter that are introduced into a laboratory medium where microbial community is cultivated. To this purpose, submicrometer particles consisting of sparingly water-soluble or insoluble soil organic matter were obtained from humic horizons of two soils by precipitation of organics dissolved in tetrahydrofuran by addition of water. The particles could then be size fractionated by centrifugation, and coarse fraction obtained from humic horizon formed under spruce forest was tested for effects on complex microbial community developing under laboratory conditions. The results indicate that low concentration (20 mg/L) of the particles is efficient to affect the composition of the bacterial community revealed by terminal restriction fragment length polymorphism. The work contributes to understanding the factors that determine the composition of soil microbial community.     

Factors controlling spatial distribution of soil acidification and Al forms in forest soils

Soil acidification and Al release in forest soils is controlled by a number of factors, like acid deposition, forest type, parent rock, altitude, etc. This paper studies the principal stand factors affecting spatial distribution of the content of KCl-extractable Al (Al(KCl), mainly exchangeable), Na4P2O7-extractable Al (Al(Na4P2O7), mainly organically bound), and other soil characteristics related to acidification in surface organic (O) and subsurface mineral (B) horizons in the Jizera Mountains region. Geostatistical methods were exploited. The highest Al(KCl) contents in the O horizons were related to high S and N content, low pH and low Ca and Mg content in soil. Liming decreased Al(KCl) contents in the O horizons. Al(Na4P2O7) in the O horizons was more abundant under spruce than under beech; in both horizons it was increased on the immission clear-cut areas populated by grass. Surface horizons are more sensitive to external influence (acid deposition, liming) and their spatial variation is stronger. In the mineral horizons, the effect of pedogenetic processes is more important. The effect of stand factors on Al behaviour is complex and often indirect, mediated for example by organic matter or soil reaction. It is difficult to clearly distinguish the effects of the particular factors.     

Characterization of Viticultural Terroirs using a Simple Field Model Based on Soil Depth – II. Validation of the Grape Yield and Berry Quality in the Anjou Vineyard (France)

Soil and climate are major constituents of the French notion of Terroir. This concept implies that there is a strong relationship between the composition of the grape, the characteristics of the wine and the territory of production. To study this link, a new method of characterization of the Terroir, including geological and pedological factors, was investigated. It uses a field model based on depth and clay content of soil, together with the degree of weathering of the parent rock. Consequently, for every type of parent rock belonging to a given geologic stage, there are a series of soils that show different stages of pedological evolution. According to the model, three kinds of soils are distinguished with regards to the weathering intensity of the parent rock, that are named weakly weathered rock (WWR), moderately weathered rock (MWR) and strongly weathered rock (SWR). By hypothesis, each soil type is considered as a homogeneous unit for vine production from the viewpoint of ecophysiological factors. Each terroir unit defined by this method is called a Basic Terroir Unit (BTU). To validate this hypothesis, experimental plots planted with Chenin and Cabernet Franc vines were studied over three consecutive seasons (2000–2002), in the Anjou vineyard (Loire Valley – France). The major BTUs developed on the two most important geological systems of Anjou (Brioverian and Ordovician–Devonian), were studied. Results showed that the berries of vines cultivated in WWR were significantly smaller, richer in sugars and anthocyanins and had a Total Phenolic Index higher than those of the vines cultivated in SWR. They also had a lower titratable acidity. Cabernet Franc vines cultivated in MWR had berries with sugar and anthocyanin contents but also total phenolics very close to those of WWR. With Chenin vines there was a good relationship between the global pool of free aromas of berries and the BTU type. The study showed significant relationships between the quality of grapes and the measured values of several ecophysiological variables such as the water supply regime or the timing of budburst.     

模拟酸沉降对南亚热带季风常绿阔叶林土壤微生物群落结构的长期影响

土壤微生物是生态系统重要的组成成分, 尤其是在土壤风化严重, 养分贫瘠的热带和南亚热带森林生态系统中, 微生物在植物养分的获取、碳循环以及土壤的形成等生态过程中的作用尤为重要。该研究基于鼎湖山南亚热带季风常绿阔叶林长期(10年)的野外模拟酸沉降实验平台, 探究了土壤微生物群落结构对土壤酸化的响应。结果表明, 酸沉降处理显著降低土壤pH (即加剧酸化)。土壤酸化对微生物生物量碳(C)含量的影响不大, 但改变了土壤微生物生物量氮(N)和磷(P)的含量, 导致表层土壤(0-10 cm)微生物生物量C:P和N:P显著提高, 表明土壤酸化可能加剧了微生物P限制。土壤酸化还显著改变了土壤微生物群落结构, 导致次表层土壤(10-20 cm)真菌:细菌显著增加。进一步分析表明, 土壤pH和土壤有效P含量是影响土壤微生物群落最为主要的两个因素。