土壤微生物生物量测定的简单方法——精氨酸氨化分析

同时测定１３种不同土壤精氨酸氨化速率、ＡＴＰ含量、微生物生物量碳和葡萄糖诱导呼吸速率。精氨酸氨化速率０．１～１７．１ｍｇＮＨ４－Ｎ／ｈ·ｋｇ土,与土壤ＡＴＰ含量、微生物生物量碳和葡萄糖诱导呼吸速率之间,存在极显著的相关性。比起其它土壤微生物生物量分析方法,精氨酸氨化法既简单、快速,又不需要昂贵的设备,可作为土壤微生物生物量测定方法。但是,当土壤含有大量易分解有机物质时,加入精氨酸时,ＮＨ４－Ｎ产生量极少,多被微生物固定。故此方法不适于此类土壤     

黄花蒿培养细胞中青蒿素合成代谢的体外调节

黄花蒿培养细胞通过两步培养积累青蒿素．第１步在含有０．２～０．４ｍｇ／Ｌ６－苄基氨基嘌呤（６－ＢＡ）和３～４ｍｇ／Ｌ吲哚乙酸（ＩＡＡ）的Ｎ６培养基中进行细胞的增殖培养,第２步将培养好的细胞转入含０．２～０．４ｍｇ／Ｌ６－ＢＡ和０．２～０．４ｍｇ／ＬＩＡＡ的改良Ｎ６培养基中进行青蒿素的合成．青蒿素的合成量为１９０μｇ／ｇ干细胞左右．当在第２步培养中加入青蒿素合成前体青蒿酸,青蒿素合成量比仅靠激素诱导提高了３倍多．青蒿素的合成途径是植物固醇合成途径的分支途径,当在青蒿素合成过程即第２步培养中加入固醇生物合成抑制剂双氯苯咪唑和氯化氯胆碱处理,可使代谢向合成青蒿素的方向移动,青蒿素合成量明显提高．经２００ｍｇ／Ｌ氯化氯胆碱处理２ｄ,黄花蒿细胞合成青蒿素量为３７２μｇ／ｇ干细胞;经２０ｍｇ／Ｌ双氯苯咪唑处理４ｄ,黄花蒿细胞合成青蒿素量为１５４０μｇ／ｇ干细胞,比靠激素诱导提高了８倍多,与诱导脱分化细胞的黄花蒿叶中所含的青蒿素（３０００μｇ／ｇ干细胞）处于同一个数量级．以上结果表明：在通过植物激素调节可以合成青蒿素的黄花蒿培养细胞中,缺乏青蒿素合成前体是青蒿素合成量低的重要原因．因此,在青蒿素合成的过程中通过体外调节,     

人工落叶松林土壤动物生物量的研究

对不同林龄人工落叶松林的土壤动物生物量的研究表明,在不同林型中,大型土壤动物占总生物量的４１．６～６４．０％,中小型土壤动物为２４．４～３９．０％,湿生动物为８．９～２５％．在土壤动物各类群中,蚯蚓生物量最大,线虫类次之,线蚓最小．土壤动物生物量与凋落物量、植被总盖度、土壤ｐＨ、土壤含水量和土壤有机质含量呈正相关关系．     

一株曲霉在石灰性土壤磷素转化中的作用

向石灰性土壤接种1株具有强烈溶解无机磷酸盐的曲霉(Aspergillus sp. 2TCiF2),并进行土壤灭菌和加入葡萄糖或玉米秸秆处理,试图了解在室内培养条件下,该菌株在土壤磷素转化中的作用。结果表明,供试菌株在土壤中能够大量繁殖,充足的碳源更加有利于其生长繁殖,微生物碳最高接近800 mg/kg土。土壤有效磷含量和溶磷量都显著提高,加入葡萄糖或秸秆并不能显著地增强其溶磷作用。微生物所溶解的磷大部分形成微生物磷,少部分释放到土壤溶液中。     

葡萄糖存在下选择性抑菌剂对土壤氮素转化的影响

采用2种氮源并分别加入选择性微生物抑制剂进行室内培养,通过测定样品中NH₄⁺-N和NO₃^--N及土壤中氨基葡萄糖和胞壁酸含量,研究土壤微生物氮素固持时间特征及其相对贡献.结果表明,加入青链霉素明显地降低了NH₄⁺-N的转化速率,且影响远大于真菌抑制剂放线菌酮;氨基葡萄糖和胞壁酸的相对比例急剧增加,而后趋于平衡;加入放线菌酮后NO₃-N转化速率持续下降,氨基葡萄糖的合成受到抑制,但加入细菌抑制剂青链霉素对其转化无显著影响.培养初期,细菌在葡萄糖存在下能快速固持NH₄⁺-N和NO₃^--N,并以NH₄⁺-N为首选氮源;培养后期,氮转化主要为真菌所推动,且真菌对NO₃^--N的利用能力显著大于细菌.     

土壤微生物生物量测定的简单方法

同时测定13种不同土壤精氨酸氨化速率、ATP含量、微生物生物量碳和葡萄糖诱导呼吸速率。精氨酸氨化速率0.1～17.1mg NH     

丹心Ⅲ号和丹心V号对血小板聚集功能的影响

本文观察了丹心Ⅲ号和丹心Ｖ号对血小板聚集功能的影响,实验结果：丹心Ⅲ号和丹心Ｖ号在体外均可显著抑制ＡＤＰ和花生四烯酸诱导的人血小板聚集,其ＩＣ５０分别为１．６０５ｍｇ／ｍｌ,２．５８９ｍｇ／ｍｌ,８．４ｌ６ｍｇ／ｍｌ和６．６０６ｎｇ／ｍｌ;在体内可抑制连续给药（３５０一７００ｍｇ／ｌｋｇ．ｄ）１０ｄ大鼠血小板对ＡＤＰ和花生烯酸诱导的血小板聚集,但对凝血酶诱导的血小板聚集无明显抑制作用。上述结果提示丹心Ⅲ号和丹心Ⅴ号对血小板聚集功能具有明显的抑制作用。     

易分解有机碳输入量对武夷山不同林型土壤激发效应的影响

土壤有机碳库是陆地生态系统中最大的碳储量库,其微小的变化也能使大气中CO₂浓度发生巨大的改变,植物来源碳的输入能通过激发效应促进或抑制土壤有机碳（SOC）的分解,对SOC的动态平衡产生影响。以武夷山三个林型（阔叶林、马尾松林、针阔混交林）土壤为研究对象,通过向土壤中添加不同量的¹³C标记葡萄糖（0、100、200、400 mg C/kg）研究易分解有机碳输入量对不同林型土壤激发效应的影响,并在此基础上探讨易分解有机碳输入量对土壤激发效应影响的作用机理。结果表明,葡萄糖输入对土壤激发效应的影响与葡萄糖输入量和林型有关。葡萄糖的输入均抑制了三个林型SOC的分解（即,呈现负的激发效应）。阔叶林土壤和针阔混交林土壤激效应强度随着葡萄糖输入量的增加而增加,而马尾松林土壤的激发效应强度对葡萄糖输入量的响应并不明显。然而在马尾松林土壤中由葡萄糖所引起的激发效应强度显著高于其他两种林型土壤。研究结果表明,易分解有机碳的输入可以抑制SOC的矿化,形成负激发效应,阔叶林土壤的激发效应强度与土壤可利用氮、葡萄糖添加量与微生物碳量比值有关,而针阔混交林与马尾松林土壤的激发效应强度分别与土壤中的放线菌和真菌有关。     

松口蘑人工菌塘诱导形成的初步研究

本研究通过土壤筛选找到适合松口蘑菌丝体生长的土壤,并在其土壤中添加适当浓度的橄榄油(0.5%-2.0%),有效地促进了菌丝体在土壤中的生长,菌丝生长状况酷似野外的松口蘑菌塘,且随着添加浓度的增加,菌丝体生物量呈明显的正相关。当土壤中橄榄油浓度为0.5%和1.0%时,松口蘑共生植物赤松苗的生长不但没有受到抑制,而且还能与菌丝体在这种“菌塘”中形成菌根。本研究成功地建立了中国松口蘑人工菌塘诱导体系,同时也为其人工子实体的诱导研究提供了必要的前提条件。     

易分解有机碳输入量对武夷山常绿阔叶林不同土层深度土壤激发效应的影响

土壤有机碳(SOC)的矿化在碳、氮循环过程中起着极为重要的作用。易分解有机碳的输入可以通过正(负)激发效应加快(减缓)原有SOC的矿化。然而,先前的研究更多关注易分解有机碳输入量对表层(0～20 cm)土壤激发效应的影响,而较少关注其对深层(20 cm)土壤激发效应的影响。本研究利用~(13)C标记葡萄糖(99 atom%)添加试验,研究葡萄糖添加量对武夷山常绿阔叶林表层(0～20 cm)和深层(30～40 cm)土壤激发效应的影响,并通过分析微生物群落组成的变化以及土壤可利用氮含量的变化探讨土壤激发效应产生的机理。结果表明:葡萄糖的添加抑制了表层和深层SOC的矿化(P0.05),使SOC的矿化量分别减少了26%～61%与62%～68%,呈现负的激发效应,但激发强度因葡萄糖添加量和土层深度而异。对于表层土壤,激发强度随着葡萄糖添加量的增加而增加;而对于深层土壤,激发强度对葡萄糖添加量的响应并不敏感。而且,葡萄糖的添加并未显著影响表层和深层土壤的微生物量碳氮含量和微生物群落组成(总磷脂脂肪酸含量;细菌、真菌、放线菌磷脂脂肪酸含量以及细菌真菌比)(P0.05)。土壤激发强度并非取决于土壤微生物群落组成,而是取决于土壤中可利用氮的含量,其可以分别解释表层和深层土壤激发效应变化的90.8%与63.4%。虽然葡萄糖的添加降低了土壤可利用氮的含量,但并未造成土壤氮的固持,这表明土壤现有可利用氮仍能够满足微生物对氮的需求。因此,在土壤矿质养分充足的情况下,微生物对外源易分解有机物的优先利用可能是负激发效应产生的主要原因。     

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.     

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。     

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.     

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.     

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.     

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.     

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.）.     

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。     

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。