Distribution of biomass in relation to environments in shrublands of temperate China

Aims Shrubland is one of the most widely distributed vegetation types in northern China. Previous studies on pattern and dynamics of plant biomass have been focused on forest and grassland ecosystems, while relevant knowledge on shrubland ecosystems is lacking. It is important to include shrublands in northern China to improve the accuracy in estimating the terrestrial ecosystem biomass in China.
Methods Based on investigations and samplings from 433 shrubland sites, we explored the distribution and allocation patterns of biomass in relation to climatic and soil nutrient factors of shrublands of temperate China.
Important findings The average shrubland biomass density in northern China is 12.5 t·hm^-2. It decreases significantly from temperate deciduous shrubland in northeast to desert shrubland in northwest. The average biomass density of temperate deciduous shrubland, alpine shrubland, and desert shrubland is 14.4, 28.8, and 5.0 t·hm^-2, respectively. Within temperate deciduous shrublands, plant biomass is lower in North China than in Northeast China. The average aboveground and belowground biomass density of shrub layer is 4.5 and 5.4 t·hm^-2, respectively; while that of grass layer is 0.8 and 1.8 t·hm^-2, respectively. Environmental factors affect biomass allocation across different plant organs. The belowground-aboveground biomass ratio of shrub exhibits no significant changes with environmental variables. The leaf-stem ratio increases with annual precipitation, and leaf biomass is low in arid region.     

Relationships among the Stem, Aboveground and Total Biomass across Chinese Forests

Forest biomass plays a key role in the global carbon cycle. In the present study, a general allometric model was derived to predict the relationships among the stem biomass Ms, aboveground biomass MA and total biomass MT, based on previously developed scaling relationships for leaf, stem and root standing biomass. The model predicted complex scaling exponents for MT and/or MA with respect to Ms. Because annual biomass accumulation in the stem, root and branch far exceeded the annual increase in standing leaf biomass, we can predict that MT ∝MA ∝ Ms as a simple result of the model. Although slight variations existed in different phyletic affiliations （i.e. conifers versus angiosperms）, empirical results using Model Type Ⅱ （reduced major axis） regression supported the model＇s predictions. The predictive formulas among stem, aboveground and total biomass were obtained using Model Type I （ordinary least squares） regression to estimate forest biomass. Given the low mean percentage prediction errors for aboveground （and total biomass） based on the stem biomass, the results provided a reasonable method to estimate the biomass of forests at the individual level, which was insensitive to the variation in local environmental conditions （e.g. precipitation, temperature, etc.）.     

基于机载激光雷达的小兴安岭温带森林组分生物量反演

使用小兴安岭温带森林机载遥感-地面观测同步试验获取的机载激光雷达(light detection and ranging, Lidar)点云数据和地面实测样地数据, 估测了典型森林类型的树叶、树枝、树干、地上、树根和总生物量等组分的生物量。从激光雷达数据中提取了两组变量(树冠高度变量组和植被密度变量组)作为自变量, 并采用逐步回归方法进行自变量选择。结果表明: 激光雷达数据得到的变量与森林各组分生物量有很强的相关性; 对于针叶林、阔叶林和针阔叶混交林三种不同森林类型生物量的估测结果是: 针叶林优于阔叶林, 阔叶林优于针阔叶混交林; 不区分森林类型的各组分生物量估测与地面实测值显著相关, 模型决定系数在0.6以上; 区分森林类型进行建模可以进一步提高生物量的估测精度。     

南亚热带常绿阔叶林优势种群的生物量与生物量增量

粘木种群的生物量为７０．１４ｔ／ｈｍ２,生物量增量为２．３２ｔｈｍ２ａ－１。其总生物量的９０％以上分布在ｄ≥２０ｃｍ的大树,仅有０．０４％～０．０５％分布在ｄ＜１０ｃｍ的小树。在各器官的分配是：树干为６５％,根为２５％,枝为１１％,而叶仅占有２％。粘木的平均径向增长为０．３５ｃｍ／ａ。应用树干解析法和形率法估算树干的生物量,两者的结果差别不大。但形率法则既省力省时,又较方便。粘木的形率为０．７１。     

选择性呼吸抑制技术在土壤细菌和真菌生物量测定中的应用

放线菌酮和链霉素可以选择性地抑制土壤真菌和细菌的葡萄糖诱导呼吸作用,但抑制效果仅５０％左右。二者的最适用量每克土分别为８～１２ｍｇ和４～８ｍｇ,培养时间以低于４ｈ为好。在两个土壤上选择性呼吸抑制方法测定的结果与直接显微镜计数法所得的结果相当,但是,加入链霉素时,一个粘性土壤的葡萄糖诱导量不但被抑制,反而随链霉素加入量的增加,诱导呼吸量增加,是否与其高的粘粒含量有关乃需要做进一步研究。另还详细地讨论     

低温等离子体生物质炼制技术

生物质炼制是世界各国的战略性研究方向。目前,主要有汽爆、酸、碱等炼制技术,而低温等离子体因具有独特的化学活性和高能量等优势而倍受青睐。本论文系统阐述了基于低温等离子体技术的生物质预处理、降解制糖、选择性功能改性、液化、气化等炼制技术的研究进展,并探讨了低温等离子体生物质炼制的机理及其今后研究发展方向。     

Effect of sensitivity to abscisic acid on scaling relationships for biomass production rates and body size in Arabidopsis thaliana

The allometric relationships for plant daily biomass production rates, different measures of body size (dry weight and length) and photosynthetic biomass per plant are reported for two mutants of Arabidopsis thaliana (abi1-1, insensitive to ABA; era1-2, hypersensitive to ABA). Scaling relationships, such as daily rate of growth (G) vs body mass (M), plant body length or plant height (L) vs body mass (M), photosynthetic biomass (M _p ) vs non-photosynthetic biomass (M _n ), and daily rate of growth (G) vs. photosynthetic biomass (M _p ) were significantly different in abi1-1 and era1-2. It is implied that the sensitivity to abscisic acid may change the scaling relationships for plant biomass production rate and body size in Arabidopsis thaliana. Because these scaling relationships are closely related to sensitivity to abscisic acid, they are of importance for phytohormonal ecology.     

珠江三角洲地区森林生物量及其动态

利用生物量转换因子连续函数法,通过69组不同龄级的森林样地实测数据,拟合了珠江三角洲主要森林类型的生物量和蓄积量之间的回归方程,并结合3个时段森林清查资料,估算了区域森林生物量及其动态.结果表明：珠江三角洲的中幼林面积占森林总面积的80％以上,其林下植被生物量约占森林总生物量的33％,充分考虑林下植被生物量能提高区域森林生物量估算的精度.在1989—1993年、1994—1998年、1999—2003年3个研究时段,珠江三角洲森林生物量共增加了14.67×10⁶ t.其中,马尾松林、常绿阔叶林和针阔混交林的生物量约占区域总生物量的80％,是区域森林生物量的主体;而中、幼林的生物量所占比例达90％,但呈逐年下降趋势.珠江三角洲快速城市化和经济发展对区域森林生物量的积累并没有产生明显影响,区域森林面积基本保持不变,而区域森林生物量呈逐年增长趋势,年增长率为1.2％.随着珠江三角洲区域中、幼林不断发育成熟,区域森林的生物量将不断增加,其环境效应也将不断增强.     

Agriculturally induced vegetation change, 1950–1975

Changes in worldwide grain production area are analyzed to assess the impact of major agricultural activity onglobal biomass. During the 26-year study period, nearly 1% of the earth's ice-free land surface was converted to grain production. This increase in agricultural area reduced the planetary biomass; however, it had minimal effect on net primary productivity. Geographically, the overall change caused by increased grain production has been to redistribute the planetary biomass poleward.     

Environmental limitation mapping of potential biomass resources across the conterminous United States

Several crops have recently been identified as potential dedicated bioenergy feedstocks for the production of power, fuels, and bioproducts. Despite being identified as early as the 1980s, no systematic work has been undertaken to characterize the spatial distribution of their long‐term production potentials in the United states. Such information is a starting point for planners and economic modelers, and there is a need for this spatial information to be developed in a consistent manner for a variety of crops, so that their production potentials can be intercompared to support crop selection decisions. As part of the Sun Grant Regional Feedstock Partnership (RFP), an approach to mapping these potential biomass resources was developed to take advantage of the informational synergy realized when bringing together coordinated field trials, close interaction with expert agronomists, and spatial modeling into a single, collaborative effort. A modeling and mapping system called PRISM‐ELM was designed to answer a basic question: How do climate and soil characteristics affect the spatial distribution and long‐term production patterns of a given crop? This empirical/mechanistic/biogeographical hybrid model employs a limiting factor approach, where productivity is determined by the most limiting of the factors addressed in submodels that simulate water balance, winter low‐temperature response, summer high‐temperature response, and soil pH, salinity, and drainage. Yield maps are developed through linear regressions relating soil and climate attributes to reported yield data. The model was parameterized and validated using grain yield data for winter wheat and maize, which served as benchmarks for parameterizing the model for upland and lowland switchgrass, CRP grasses, Miscanthus, biomass sorghum, energycane, willow, and poplar. The resulting maps served as potential production inputs to analyses comparing the viability of biomass crops under various economic scenarios. The modeling and parameterization framework can be expanded to include other biomass crops.     

内蒙古草地样带植物群落生物量的梯度研究

采用样带法对内蒙古草地植物群落生物量沿水热梯度的变化特征进行了研究,并对几种回归方法进行了比较。一元回归结果表明:在本样带的限定范围内,生物量与年均温、≥0 ℃年积温、≥10 ℃年积温、年实际日照总时数等热量因子呈负相关(年均温的相关性最高),而与年降水量、年均相对湿度等水分因子呈正相关(年均相对湿度的相关性最高),其中年均温和年均相对湿度对生物量的影响最为显著,二者对生物量的空间变异起着互为消长的作用,而海拔高度的影响则不显著。多元回归结果表明,作为半干旱区植物生长的主要限制因子,年降水量在大尺度上对生物量产生影响的途径更为复杂,但其作用不可低估。生物量和地下地上生物量比值会因不同的气候区、不同的植被类型和物种组成,对环境因子的响应程度不同,在经向、纬向和草地类型梯度上的变化特征也不同。水热的配比关系要比单一的水分和温度与植物的生长具有更紧密的关系,地下地上生物量比随着水热配比关系的变化也会呈现出不同的变化规律,其驱动因子并不一定始终都是降水。也许可以认为:半干旱/干旱的划分界限是本研究所涉及的草地样带上生物量和地下地上生物量比值沿草地类型梯度变化的一个转折界限,在此界限前后,气候对生物量的主导因素和生物量对此关键因子的响应程度都有所变化。     

Sensitive assay of phospholipid glycerol in environmental samples

Measurement of very low levels of microbial biomass was achieved by determining the glycerol content of the phospholipids from environmental samples. Successive application of acid methanolysis and hydrofluoric acid hydrolysis was used to release glycerol from the phospholipids. The glycerol, once released, was acetylated and analyzed by capillary gas-luquid chromatography (GLC). The analysis was sensitive to 10^?11 moles by GLC waith flame ionization detection and GLC/mass spectrometry with selective ion monitoring. Estimation of the microbial biomass by the lipid phosphate correlated with the glycerol phosphate measured by the hydrolytic procedures. In addition, indication of the community composition was gained by analysis of the acid labile glycerol. Application of this methodology to the sparse of the ground water sediments showed agreement with other estimates of microbial biomass.     

The dynamics of microflora and the occurrence of phytotoxic substances in different soils with corn residues and inorganic nitrogen

In an incubation experiment the development dynamics of bacterial and fungal communities as well as the level of phytotoxicity were analysed in sand and three soils differing in mechanical structure and amended with corn residues and mineral nitrogen. Bacterial biomass was positively correlated with the degree of dispersion of the solid phase of the soil, whereas the ratio of fungal to bacterial biomass (F:B) was found to be negatively correlated. Fungi were much more tolerant to carbon or nitrogen deficit than bacteria. Introduction of the plant material alone, characterized by a broad carbon to nitrogen ratio, led to the domination of fungi in microbial communities. The level of soil phytotoxicity built up with increasing level of crop residues. Phytotoxicity was observed for the longest time period in soil with the highest silt and clay content. The narrowing of the C:N ratio at introduction of the appropriate amount of mineral nitrogen (larger in heavier soils) resulted in accelerated disappearance of phytotoxicity and at the same time favoured bacterial development. This points to a significant participation of bacteria in the degradation of phytotoxic substances in the soil.     

能源植物芒草研究进展与综合利用现状

芒草是一类多年生的C4草本植物,因其具有生物量大、纤维素含量高、灰分低、热值高、适应性强、生产成本低等诸多优点被认为是目前最具开发潜力的高产纤维类能源植物之一,因而成为国内外关注和研究的热点。综述了国内外能源芒草的研究进展与综合利用现状,并展望了今后的发展前景。     

施氮对几种草地植物生物量及其分配的影响

为了研究施氮对不同草地植物生物量及其分配的影响,以及温带草地生态系统碳交换过程对氮素的响应,在内蒙古太仆寺旗农田-草地生态系统野外站,以4种草地植物:紫花苜蓿(Medicago sativa L.)、高丹草(Sorghum bicolor L.) 、羊草(Leymus chinensis T.)和小叶锦鸡儿(Caragana microphylia L.)为材料,进行了3种氮素水平 的盆栽控制实验。研究结果表明:施氮显著促进了4种植物地上生物量的积累,紫花苜蓿在中氮水平地上生物量最大,较对照增加了24.8%,高丹草、羊草、小叶锦鸡儿在高氮水平地上生物量最大,分别较对照增加了45.6%、39.3%和72.2%。4种植物在中氮水平地下生物量最大,而细根(直径≤2mm)生物量随施氮量的增加显著减少。羊草根茎生物量及其分配比例随施氮量的增加而增大。施氮显著降低了4种植物的根冠比,紫花苜蓿的根冠比在中氮水平时最小,为1.62,高丹草、羊草、小叶锦鸡儿的根冠比在高氮水平时最小,分别为0.57、1.02和0.41。随施氮量的增加,植物地下部分特别是细根的分配比例显著降低,地上部分分配比例显著增加。不同植物对施氮水平的响应不同,相比豆科植物,施氮显著促进禾本科植物生物量积累,并使其生物量分配格局发生显著改变。     

贵州普定喀斯特次生林乔灌层地上生物量

生物量是植物群落最重要的特征之一, 也是研究生态系统基本过程和功能的重要参数。我国西南喀斯特山地次生林是退化生态系统恢复过程中的重要阶段, 其生境特殊, 乔灌层种类繁杂且生长形态多样, 物种间体积质量密度差异悬殊, 生物量测定极为困难。所以, 有关其生物量的基础资料极为缺乏。该文根据对普定喀斯特生态站的窄叶石栎(Lithocarpus confinis)+云南鼠刺(Itea yunnanensis)林、圆果化香(Platycarya longipes)+云南鼠刺林、圆果化香+槲栎(Quercus aliena)林3个主要次生森林类型的样地调查资料, 采用样木回归模型法和收获法, 研究了群落乔灌层地上生物量及其分配格局。利用172株样木数据建立了圆果化香、窄叶石栎、云南鼠刺、刺楸(Kalopanax septemlobus)、安顺润楠(Machilus cavaleriei)、槲栎、香叶树(Lindera communis)、川钓樟(Lindera pulcherrima var. hemsleyana)、异叶鼠李(Rhamnus heterophylla)、倒卵叶旌节花(Stachyurus obovatus)、薄叶鼠李(Rhamnus leptophylla)、贵州花椒(Zanthoxylum esquirolii)、竹叶椒(Zanthoxylum planispinum)、铁仔(Myrsine africana)和刺异叶花椒(Zanthoxylum dimorphophyllum var. spinifolium)15个主要树种的分种生物量回归模型。同时, 利用这些样木建立了3个不同胸径(D)组(D＜1 cm、1 cm≤D≤5 cm和D>5 cm)的生物量回归模型。通过进一步分种和分组的计算得出: 这3个次生乔木林的乔灌层地上生物量分别为85.6×10³、65.3×10³和115.2×10³ kg·hm^-2; 层次分配上, 3个样地的乔木层地上生物量占绝对优势, 分别约占乔灌层地上生物量的98.5%、96.6%和99.0%; 径级分配上, 3个样地的生物量主要集中在大径级(D≥10 cm)的个体上; 物种分配上, 3个样地的生物量排序前10位的物种分别约占乔灌层地上生物量的99.3%、97.3%和99.0%, 并集中分配在少量优势树种中。     

Length‐weight relationships for small Midwestern US fishes

Herein, we provide length‐weight relationships for juvenile and smallbodied freshwater fishes of 20 species. Length‐weight parameters were estimated using data collected through four years of electrofishing surveys conducted in the rivers of Illinois, USA.     

Carbon-based Secondary Compounds at Elevated CO2

From literature sources we compiled the data on carbon-based-secondary compounds CBSC (phenolics and terpenoids) and biomass of 17 plant species grown at different CO₂ concentrations under low and high nutrient availabilities. With a low nutrient availability a possible inverse correlation was found between the biomass and CBSC changes. On the contrary, under a high nutrient availability, both the CBSC and biomass increased with elevated CO₂. The wide variation in the CBSC production among species and compounds (larger responses in phenolics than in terpenoids) indicates that the allocation to CBSC may not completely be governed by changes in CO₂ and nutrient availabilities per se. Yet the comparison shows that elevated CO₂ generally loads the carbon into CBSC [their leaf concentration increased an overall average of 14 % at 700 umol(CO₂) mol-r] which may improve our understanding of the carbon storage and cycling in ecosystems under the “global change” of climate. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于树木起源、立地分级和龄组的单木生物量模型

以马尾松(Pinus massoniana)和落叶松(Larix)的大样本实测资料为建模样本,以独立抽取的样本为验证样本,把样本按起源、立地和龄组进行分级,采用与材积相容的两种相对生长方程,分普通最小二乘和两种加权最小二乘,对地上部分总生物量、地上各部分生物量和地下生物量进行模型拟合和验证,使用决定系数、均方根误差、总相对误差和估计精度等8项统计量对结果进行分析。结果表明:两个树种地上部分总生物量,立地分类方法,模型的拟合结果和适用性都最优;马尾松VAR模型较优,而落叶松CAR模型较好;两种加权最小二乘方法,在建模样本和验证样本中表现得不一致。在建模样本中,加权回归2(权重函数1/f^0.5)略优于加权回归1(权重函数1/y^0.5),但在验证样本中,加权回归1却明显优于加权回归2。而同时满足建模样本拟合结果最优和验证样本检验结果最优的组合中,只有加权回归1。两个树种地上部分各分量生物量,模型拟合结果和适用性,均为干材最优,树叶最差、树枝和树皮居中,样本分类、模型类型和加权最小二乘方法对干材生物量的影响,规律和地上部分总生物量相同;样本分类、模型类型和加权最小二乘方法的最优组合,用验证样本检验的结果,总相对误差树枝不超过±10.0%,树皮不超过±5.0%,树叶马尾松不超过±30.0%,落叶松不超过±20.0%。两个树种地下部分(根)生物量,样本按龄组分类方法,模型拟合结果最优,与材积相容的模型总体上优于与地上部分总生物量相容模型。