青冈常绿阔叶林氮的生物循环

对分布于浙江建德的青冈常绿阔叶林N的生物循环进行了研究.群落各代表种类的N浓度在0.49%～1.64%之间,其中下木层、草本层和藤本植物中N的浓度远大于乔木层和亚乔木层的种类;乔木层和亚乔木层4种器官中N的浓度基本为叶＞枝＞根＞干,其他层次的种类则为地上部分＞地下部分.乔木层青冈不同器官中N浓度的高低顺序为花序＞嫩叶＞老叶＞嫩枝＞老枝＞细根＞树干、粗根.各器官中N浓度的季节变化不是很大,其根、枝和叶中的N浓度均在秋季(10月份)最高;下木层青冈各部位N浓度在1月份最高.不同径级青冈中N浓度变化无明显规律.N元素在不同类型凋落物中的浓度范围为0.74%～2.30%,降水和穿透水中的N浓度分别为0.000038%和0.00009%,N在死地被层中的浓度为1.94%,土壤中N的浓度为0.59%.N在植物群落中现存量为1025.28 kg/hm2,死地被层中积累量为224.88 kg/hm2,土壤(A0～B层)中储存量为55151kg/hm2.群落中N的存留量为119.47 kg/(hm2·a);归还量为84.13 kg/(hm2·a),其中通过凋落物的为78.49kg/(hm2·a),通过穿透水的为5.64 kg/(hm2·a);吸收量为203.60 kg/(hm2·a).降水输入了4.88 kg/(hm2·a)的N.     

铀的生物成矿作用及成矿过程中矿质元素循环

概述了微生物成矿作用,并介绍了硫杆菌、硫酸盐还原菌、铁细菌、硝化细菌、反硝化细菌等各种细菌在与铀的生物成矿过程相关的地质元素循环中所起到的作用。并展望了今后矿床中微生物种群的研究方向。     

西双版纳热带季节雨林生态系统氮的生物地球化学循环研究

 用小流域集水区和物质平衡方法,于1999年对西双版纳热带季节雨林生态系统的氮素循环进行了初步研究。西双版纳季节雨林生态系统的氮库总储量为6 481.2 kg·hm-2,其中活体生物量、凋落物层和土壤（0～30 cm）中的氮储量分别为970.9、37.7、5 481.2 kg·hm-2。土壤中的氮占生态系统氮总储量的84.4%,活体生物量占15.0%,凋落物层仅占0.6%。结果表明季节雨林的氮主要分布在土壤中,而在生物量中只占很少部分。大气降水、林内穿透水、树干流及地表径流的氮含量分别为0.565、0.828、0.983和1.042 mg·dm-3,氮通量则分别为8.89、10.97、3.57、5.95 kg·hm-2·a-1。大气降水输入氮8.89 kg·hm-2·a-1,径流输出氮5.95 kg·hm-2·a-1, 收支平衡（输入—输出）为2.94 kg·hm-2·a-1。氮的生物循环：吸收为149.86 kg·hm-2·a-1,存留为69.30 kg·hm-2·a-1,归还为80.56 kg·hm-2·a-1,循环系数为0.54。结果表明未受干扰的季节雨林生态系统处于氮积累的状态,有利于该生态系统的稳定与持续发展。     

生物炭对土壤氮循环的影响研究进展

在定性资料调研的基础上,基于ISI Web of Science数据库,采用文献计量学方法,针对"生物炭对土壤氮循环的影响"及其分支技术进行文献检索、数据整理、分类以及主题分析,从国际整体研究态势和分支技术主题两个角度探讨了目前国内外生物炭影响土壤氮循环方面的研究进展,并从生物炭对土壤N_2O排放、肥料利用率、硝化速率、NH_4~+/NH_3吸附、NO_3~-吸附以及土壤微生物氮素固持等6个方面的影响进行了详细论述。近年来,生物炭对土壤氮循环的影响研究急剧增温,发文量逐年增加,截止2014年6月,SCI数据库中共检索到2468篇论文。其中,期刊论文2188篇、综述性论文93篇,其它类论文177篇。美国、加拿大、英国等欧美国家在该领域的研究中占有明显优势,而自2010年以来,中国已成为该领域全球第一的年发文大国。发文热点主要集中在生物炭对土壤N_2O排放和对氮肥利用率的影响2个方面,占总发文量的73.7%。从6个方面的分支技术主题来看,生物炭的影响作用争议性较大。大部分研究认为,生物炭能够抑制土壤N_2O排放、提高氮肥利用率、促进土壤硝化速率、提高土壤对NH_4~+/NH_3和NO_3~-的固持作用以及土壤微生物氮素固持作用等,但也有研究表明生物炭会促进土壤N_2O排放、抑制土壤硝化速率,且不具备NO_3~-固持能力。这主要与生物炭的类型、老化过程,以及土壤类型及其含水孔隙率等密切相关。总之,探讨了生物炭对土壤氮循环影响的研究动态、热点及主要结论,为深入了解生物炭对土壤理化特性影响的作用机制提供了一定研究思路,为生物炭的农业应用提供了一定借鉴和参考。     

油松不同种源在北京地区水势和蒸腾速率的比较研究

应用压力室技术和稳态气孔仪,测定了在北京地区8年生人工油松林,7个气候生态型13个种源的水势值季节变化和蒸腾速率的日变化及季节变化。结果表明,油松各种源一年中,水势值最低的是严冬季节(-19.75巴)和高温干旱期(-14.81巴)。从不同生态型水势值来看,差异明显。无论在严寒的一月还是在高温干旱的六月,东北型水势值最高,其次是西北型,南部型最低。西南型略高于南部型。水势值高低还明显表现与越冬死亡率高低的关系,南部型种源水势值最低,越冬死亡率也最高。各种源蒸腾速率日变化和季节变化有明显的规律,与环境因子(光照、气温、大气湿度) 密切相关。在日变化中呈现早、晚低,中午高的“凸形峰曲线”。随着春季温度升高,在季节变化中,五月份升至第一高峰,而六月高温干旱期,蒸腾速率明显下降,形成一个低谷。雨季以后的8、9月份升至全年最高值,11月秋末冬初又下降至很低。全年呈现一双峰曲线。从各生态型种源蒸腾速率来看,差异是很明显的,以东北型最高,其次是西北型,中部型,中西型居中,西南型,南部型最小。除上述外,从针叶形态解剖特征上来看,各生态型也差别明显,东北型、西北型的针叶短、窄、薄,表皮和皮下组织则较厚,而南部型种源的针叶长、宽、厚,表皮及皮下组织则较薄。这均反映了不同生态型避旱机制的差异。     

密云水库水源保护区板栗林主要养分元素生物循环研究

对密云水库北京集水区板栗林主要养分元素循环进行了研究。结果表明,22年生板栗林的生物量为38638kg·hm^-2;板栗林5种主要养分元素N、P、K、Ca、Mg贮存量为315．38kg·hm^-2,各器官中5种元素贮存量大小排序是干>枝>根>叶>花>果苞>果。板栗林生态系统乔木层每年从土壤中吸收的5种养分元素量为79．17kg·hm^-2,吸收量占0～30cm土层5种养分元素总量的0．15％,占0～30cm土层中5种元素有效养分量的1．95％。年吸收量中存留量为11．25kg·hm^-2,枯落物归还量为58．08kg·hm^-2。雨水及雨水淋溶输入到板栗林生态系统的养分元素量为38．63kg·hm^-2,果实输出量为9．84kg·hm^-2。雨水和雨水淋溶量与枯落物归还量之和大于吸收量,表明研究期间板栗林生态系统养分元素的收入略大于支出,5种元素的吸收系数排序为N>P>K>Ca>Mg,利用系数排序为K>N>Mg>P>Ca。循环系数排序为K>N>P>Mg>Ca。周转期排序是Ca>P>Mg>N>K。     

三种棕榈植物的热值及灰分含量比较研究

通过测定厦门的三种棕榈植物布迪椰子、油棕和沼地棕的不同组分的热值和灰分含量。结果表明,布迪椰子各组分干重热值和去灰分热值由大到小的顺序为成熟叶>细根>幼叶>粗根>根茎>叶柄;油棕的为成熟叶>粗根>细根>幼叶>叶柄>根茎;沼地棕的为成熟叶>粗根>细根>幼叶>叶柄。布迪椰子的灰分含量高低顺序为细根>粗根>根茎>幼叶>叶柄>成熟叶,油棕的为成熟叶>幼叶>细根>粗根>叶柄>根茎;沼地棕的为幼叶>成熟叶>细根>粗根>叶柄。布迪椰子和沼地棕成熟叶的热值显著高于油棕,并且布迪椰子的成熟叶热值略低于沼地棕,但布迪椰子幼叶的热值显著高于沼地棕和油棕,布迪椰子的叶柄的热值显著低于沼地棕和油棕,说明耐寒性强的布迪椰子热值和灰分比耐寒性弱的油棕的分配策略更加合理,有利于提高其对低温的适应性,对植物引种具有重要的指导意义。     

鄂西南不同核用银杏品种叶中主要黄酮苷元及碳、氮元素含量比较研究

为了比较鄂西南不同核用银杏品种叶中主要黄酮苷元含量,并进一步探讨影响其含量的因素,采用RPHPLC法对样品中黄酮苷元进行定量分析,同时采用德国elementar vario MICRO CUBE元素分析仪测定样品中碳、氮等元素含量。结果表明:不同银杏品种叶片中黄酮含量存在差异,三种主要黄酮苷元组成比例在各品种间差异更加显著,恩银15号及恩银23号具有较好苷元比例,可以作为叶用银杏发展的优先考虑品种。进一步分析表明,叶片总黄酮含量与叶中氮含量之间显著正相关,提示合理施氮有助于改善三种苷元的比例关系,从而使其比例达到最佳。通过比较鄂西南不同银杏品种银杏叶中有效成分的含量,为提高银杏叶质量,优化银杏叶资源提供了理论依据。     

不同产地松茸氨基酸与矿质元素的比较研究

以西南地区的三种松茸子实体为材料 ,用柱前衍生高效液相色谱法和原子吸收分光光度法分别对松茸子实体的氨基酸和矿质元素进行了测定 ,氨基酸的测定结果表明 :采自四川通江的松茸子实体的氨基酸总含量最高 ,为 10 .5 82 % ;其次为采自重庆的松茸子实体为 9.6 0 7% ;最低的为采自云南昌隆的松茸子实体 ,为 3.381%。矿质元素的测定结果表明 :所测定的七种元素中 ,含量较高的有三种 ,分别为K ,Ca和Mg ,平均含量分别为 3.1× 10 4mg/Kg ,1.6 2× 10 3mg/Kg和 5 .5 8× 10 2mg/Kg。在这三种松茸子实体中云南昌隆的Fe ,Mn含量最高 ,分别为 6 2 .2 82mg/Kg和 6 .0 6 4mg/Kg ;重庆的Cu含量最高 ,为 5 2 .84 5mg/Kg;Zn的含量在这三种子实体中差异不大。     

施锌对石灰性褐土上小白菜光合作用及保护酶活性的影响

通过田间试验的方法,采用30(低锌)、75(中锌)和120kg/hm2ZnSO4(高锌)3个施锌水平,研究施锌对山西省石灰性褐土上小白菜叶片叶绿素含量、净光合速率、硝酸还原酶(NR)活性、抗氧化酶活性及丙二醛(MDA)含量的影响.结果表明:随着施锌量的提高,小白菜叶片各叶绿素组分含量、总叶绿素含量、净光合速率和NR活性均呈先升后降的变化趋势,并均以中锌处理最大,且中、高锌处理显著高于对照(不施锌);小白菜叶片过氧化物酶(POD)和过氧化氢酶(CAT)活性也呈先升后降的趋势,而超氧化物歧化酶(SOD)活性持续增加,CAT、POD和SOD活性分别在低锌、中锌和高锌处理时达到最大值,所有施锌处理的3种保护酶活性均显著高于缺锌对照;各处理小白菜叶片MDA含量随着施锌量增大而逐渐降低,且所有施锌处理均显著低于缺锌对照.研究发现,施锌能有效增强石灰性褐土上小白菜叶片光合能力和氮同化能力,显著提高其抗氧化酶系活性,并以75kg/hm2ZnSO4效果最佳.     

Effect of Heterodera glycines on Yields of Nonnodulating Soybeans Grown at Various Nitrogen Levels

Response of a nonnodulating soybean strain to infection by Heterodera glycines was greatly affected by applications of NaNO₃. Soybean yields from nematode infested microplots were reduced 71.8, 44.4, and 10.7% at low, medium, and high N levels, respectively, when compared with yields of noninfested plots at similar N levels. The results indicate that besides reducing root nodulation and N fixation, H. glycines causes soybean yield reductions by inciting deleterious host responses that increase with N deficiency.     

Effects of Elevated Carbon Dioxide and Nitrogen Fertilization on Mycorrhizal Fine Roots and the Soil Microbial Community in Beech-Spruce Ecosystems on Siliceous and Calcareous Soil

To study the responses of forests to global change, model ecosystems consisting of beech and spruce trees were maintained in open top chambers for 4 years under four conditions, namely with normal and elevated CO2 and with low and high nitrogen input, each replicated four times. Each open top chamber (height 3 m, diameter 3 m, soil depth 1.5 m) contained two separate soil compartments containing nutrient-poor siliceous and nutrient-rich calcareous soil. Here, we focus on the fine roots and the soil microbial community in these model ecosystems. At the time of planting, the fine roots were cut back according to forestry practice, and the newly formed roots were colonized by the indigenous soil microflora. After 4 years, the total biomass of fine roots, when averaged over all treatments, was almost the same in each of the two soil types; it was highest in the top 100 mm of soil (60%) and decreased sharply in deeper soil layers. Fungal biomass associated with the fine roots, consisting mainly of ectomycorrhizal fungi, was estimated using the ergosterol content as a marker. It was much higher in fine roots in the siliceous than in the calcareous soil, indicating considerably enhanced ectomycorrhiza formation in the nutrient-poor siliceous soil. Elevated atmospheric CO2 stimulated fine root production by ca. 85% and 43% in the top 100 mm of calcareous and siliceous soils respectively. Increased nitrogen input caused a slightly reduced production of fine root biomass in the calcareous soil but increased it by 33% in the siliceous soil. Marker substances for microorganisms were analyzed in the root-free soil. The amounts of carbon released by fumigation/extraction (a general marker for microbial biomass) and chitin (a marker for fungal biomass) were significantly higher in the top layer of the siliceous than of the calcareous soil, but they did not respond significantly to the treatments with elevated CO2 or the nitrogen fertilizer. The total concentration of the phospholipid fatty acids (PLFAs) and the number of the PLFAs did not differ between the two soil types. However, four of the eight most abundant PLFAs differed significantly between the two soil types. Principal component analysis revealed clearly separated clusters for the two soil types. Although analysis did not reveal any significant changes in response to the treatments, the concentration of the PLFA typical for ectomycorrhizal fungi was significantly higher under conditions of elevated CO2 in the nutrient-rich calcareous soil.     

Mineral Elements in Root of Wild Saposhnikovia divaricata and Its Rhizosphere Soil

Mineral elements are important components of medicinal herbs, and their concentrations are affected by many factors. In this study, Ca, Mg, Na, K, Fe, Mn, Cu, and Zn concentrations in wild Saposhnikovia divaricata and its rhizosphere soil collected from seven locations at two different times in China were measured, and influences of rhizosphere soil on those minerals in plant were evaluated. The results showed that mean concentrations of eight minerals in plant samples decreased in the order: Ca > Mg > Na > K > Fe > Zn > Mn > Cu, and those in the soil samples followed the following order: Na > Fe > Ca > K > Mg > Mn > Zn > Cu. Mean concentrations of Ca, Na, Mg, and K in plants were higher than those in soils, while higher mean concentrations of the other four minerals were found in soils. It was found that there was a positive correlation of Mg, Na, and Cu concentrations in the plant with those in the soil respectively, but a negative correlation of Mn concentration in plant with that in the soil. Except Ca, K, and Mn, the other five minerals in plant were all directly affected by one or more chemical compositions of soil. The results also indicate that pH value and concentrations of total nitrogen, Mg, Mn, and Cu in soil had significant correlations with multimineral elements in plant. In a word, mineral elements uptake of S. divaricata can be changed by adjusting the soil fertility levels to meet the need of appropriate quality control of S. divaricata.     

Study on Mineral Elements in Salvia roborwskii from the Qinghai-Tibet Plateau

The contents of trace elements, including aluminum, barium, beryllium, calcium, cobaltium, chromium, copper, iron, potassium, lanthanum, lithium, magnesium, manganese, sodium, nickel, phosphorus, lead, sulfur, silicon, titanium, vanadium, and zinc, were determined by ICP-AES. The mean concentrations of the 22 elements were as follows: K>Ca>Mg>Fe>Al>Na>S>P>Ba>Ti>Mn>Zn>Sr>Cu>Ni=Cr>Pb>V>Li=La>Co>Be. Principal components analysis of SPSS was applied to study the characteristic elements in Salvia roborwskii. Five principal components which accounted for 89.288% of the total variance were extracted from the original data. The first factor accounted for 56.401% of the total variance, which meant that aluminum, barium, beryllium, calcium, and cobaltium were the characteristic elements in S. roborwskii. This useful new method was used to evaluate the quality of S. roborwskii, and to provide the scientific foundation for its utilization and further research.     

Microbiota in Wheat Roots,Rhizosphere and Soil in Crops Grown in Organic and Other Production Systems

Culturable microbial communities and diseases were compared in organic, integrated and conventional systems of winter wheat production and monoculture. Particular emphasis was placed on the density and diversity of cereal pathogens and their potential antagonists, and on the association of the active microbial populations with the health and productivity of wheat. In roots, rhizoplane and rhizosphere, fungi tended to be most abundant in the integrated system or monoculture, and bacteria in the organic system. The dominant fungal groups (with individual frequency >5%) included root pathogens (Fusarium, Gibberella, Haematonectria and Ilyonectria) and known pathogen antagonists (Acremonium strictum, Clonostachys, Chaetomium, Gliocladium and Trichoderma spp.). The 50 subdominant species (with individual frequency 1–5%) included the pathogens Alternaria, Cladosporium (leaf spot), Gaeumannomyces graminis (take‐all), Glomerella graminicola (anthracnose), Oculimacula yallundae (eyespot), Phoma spp. (leaf spots), and Pythium and Rhizoctonia (root rot). The 40 subrecedent species (with individual frequency <1%) included minor pathogens (Botrytis, Coniothyrium, Leptosphaeria). Antagonists in roots, rhizoplane and rhizosphere were most frequent in the organic system and least frequent in monoculture, suggesting that these systems had the most and least disease‐suppressive habitats, respectively. The other two systems were intermediate, with microbial communities suggesting that the conventional system produced a slightly more suppressive environment than the integrated system. The highest grain yield, in the integrated system, was associated with high abundance of fungi, including fungal pathogens, lowest abundance of Arthrobacter, Pseudomonas and Streptomyces in roots, rhizoplane and soil, and relatively high stem‐base and leaf disease severity. The lowest grain yields, in the organic system and monoculture, were associated with less abundant fungi and more abundant Pseudomonas. There is no clear indication that yields were affected by diseases.     

Biodegradation of Diesel Fuel in Soil Under Various Nitrogen Addition Regimes

Bioremediation is a growing technology for treating fuel-contaminated soils. Many biological, physical, and chemical parameters control the rate and efficiency of this process, including type and concentration of contaminants, temperature, oxygen content, and nutrient status. This study investigated the effect that nitrogen sources and concentrations had on the degradation rate of diesel fuel in nutrient limited soil at two carbon-to-nitrogen ratios. The different sources of nitrogen studied were ammonium nitrate, ammonium sulfate, potassium nitrate, urea, and urea oligomers (control release fertilizer). Laboratory experiments were conducted on field-contaminated soil using sealed bioreactors at a controlled temperature of 25°C. For both carbon-to-nitrogen ratios tested, hydrocarbon degradation rates were the highest for the ammonium sulfate (20:1 at 0.032?d^?1; 40:1 at 0.019d^?1) and urea treatments (20:1 at 0.025?d^?1; 40:1 at0.011?d^?1). A degradation rate correlation as a function of nitrate and ammonia concentrations was developed. The correlation suggests the occurrence of nitrate inhibition at elevated nitrate concentrations.     

不同红树林土壤中的PHAs合成菌研究

通过平板分离和傅立叶红外光谱检测技术分析了PHAs合成菌在7个红树林土壤生境中的分布,结果表明:红树林土壤中PHAs合成菌数量在103~106cfu/g湿土之间,占异养菌总数的1.5‰~318.6‰;不同红树林土壤中PHAs合成菌分布差异明显,回归分析显示在10%的置信水平下,样品中PHAs合成菌数在一定范围内与土壤中有效钾、全磷呈显著相关;在全磷含量高的深圳和福建样品中,高PHAs合成能力的菌株数显著高于其它样品,进一步表明PHAs合成菌可能与环境污染程度有关。     

The Study on the Correlation Between Six Kinds of Mineral Elements and Diabetes

The study aimed to explore the relationship of six kinds of mineral elements and diabetes among adults in northeast China. A cross-sectional survey was conducted in Jilin Province, northeast China. A total of 366 males and 204 females aged 18 ~ 77 years from Jingyu town, Dongliao town, and Changling town were included using a multistage stratified random cluster sampling design. Data was obtained from face to face interview, physical examination, and laboratory measurement. We defined the normal people (3.9 ~ 6.0 mmol/L), impaired fasting glucose (IFG) individuals (6.1 ~ 6.9 mmol/L), and diabetes mellitus (DM) (> 7.0 mmol/L) according to the WHO diagnostic criteria. Kruskal-Wallis test, Spearman rank correlation, as well as binary logistic regression were used to analyze influencing factors. lg(Cu/Zn)was correlated with DM (OR 8.390; 95% CI of OR 1.272–55.347). The specific mineral elements such as Zn, Ca, as well as Cu/Zn ratio may be the potential risk factors for diabetes. So, the supplement or reduction of these elements is supposed to be told to IFG to prevent or delay the occurrence of diabetes or DM to avoid its complication.     

Mineral Elements of Subtropical Tree Seedlings in Response to Elevated Carbon Dioxide and Nitrogen Addition

Mineral elements in plants have been strongly affected by increased atmospheric carbon dioxide (CO₂) concentrations and nitrogen (N) deposition due to human activities. However, such understanding is largely limited to N and phosphorus in grassland. Using open-top chambers, we examined the concentrations of potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), copper (Cu) and manganese (Mn) in the leaves and roots of the seedlings of five subtropical tree species in response to elevated CO₂ (ca. 700 μmol CO₂ mol^-1) and N addition (100 kg N ha^-1 yr^-1) from 2005 to 2009. These mineral elements in the roots responded more strongly to elevated CO₂ and N addition than those in the leaves. Elevated CO₂ did not consistently decrease the concentrations of plant mineral elements, with increases in K, Al, Cu and Mn in some tree species. N addition decreased K and had no influence on Cu in the five tree species. Given the shifts in plant mineral elements, Schima superba and Castanopsis hystrix were less responsive to elevated CO₂ and N addition alone, respectively. Our results indicate that plant stoichiometry would be altered by increasing CO₂ and N deposition, and K would likely become a limiting nutrient under increasing N deposition in subtropics.