九连山国家级自然保护区海南鳽栖息地及活动时间的初步观察

在江西九连山国家级自然保护区对海南鳽(Gorsachius magnificus)栖息地及活动时间进行了初步考察，结果表明，较高的植被覆盖度(90％以上)和密度有利于海南鳽的隐蔽，并满足其躲避敌害的要求；海南鳽对栖息地的坡度选择性不明显，而对坡向的选择性较明显；海南鳽主要栖息在海拔500m以下，而且多选择溪水流动缓慢、有浅水区或大片沙滩及鱼虾充足的地方作为觅食地；4～6月份海南鳽活动的频次较高，可能是海南鳽在九连山的繁殖育雏期。     

上思县海南嗀活动区的水鸟研究

海南（开 鸟）(Gorsachius magnnficus)是世界上最为濒危的鸟类之一。在上思县海南的活动区，分布有水鸟32种；其中在海南（开 鸟）主要觅食地浅水区活动的有14种，包括11种白昼活动的水鸟和3种夜行性水鸟，海南（开 鸟）属夜行性水鸟。由于生境使用时间不同，海南（开 鸟）与大部分白昼活动的水鸟形成生态分隔；夜鹭在觅食生境的使用和活动时间上，与海南（开 鸟）重叠最多，有可能对海南（开 鸟）产生重要的生态影响，值得进一步深入研究。研究还表明，冬季和初春是调查海南（开 鸟）的分布和数量的重要季节。     

陕西省红富士苹果果园施肥调查

对陕西省红富士苹果果园施肥调查表明，追求产量，超量施肥比较普遍，各县之间果园施肥水平差异很大，用肥比例不合理，低钾和不施钾的占７７％，初挂果和盛果期果园氮磷钾（Ｎ、Ｐ２Ｏ５、Ｋ２Ｏ）用量，以每亩３０－５０ｋｇ为宜，有机肥３０００－５０００ｋｇ，用肥比例Ｎ：Ｐ２Ｏ５：Ｋ２Ｏ为１：０．５－１：０．６－０．８。     

黄颡鱼Sox9基因的分离及分析

Sox9基因是号陛别分化形成有关的重要基因之一。以黄颡鱼（Pelteobagrus fulvidraco）为研究材料，使用RT-PCR在脑、精巢和卵巢分离和克隆到了黄颡鱼Sox9基因，序列比对分析表明，脑和精巢Sox9基因序列一致，称Sox9al（GenBank accession No．AY684328），卵巢的则与其有差异称Sox9a2（GenBank accession No．AY684329）。Sox9al与Sox9a2的核苷酸相似性为77％，氨基酸的相似性为84％，可以认定是由两个基因表达的。和其它动物Sox9氨基酸序列的同源性分析表明：黄颡鱼Soxga1与其它动物Sox9的相似性在8l％，89％之间，平均在86％左右；黄颡鱼Sox9a2的相似性在76％～86％，平均在83％左右。系统树分析揭示了Sox9为单起源，遗传距离远近也与传统分类结果一致。使用RT-PCR对Sox9a1与Sox9a2在雌雄黄颡鱼前脑和性腺组织的表达检测结果显示，Sox9a1在雌雄鱼的前脑和性腺均有表达，但Sox9a2只在卵巢表达，说明该基因可能与雌性性别形成及卵巢发育具有调控作用。     

有机无机肥配施对菠萝蜜种植土壤线虫群落的影响

为探究有机肥施用对菠萝蜜种植土壤线虫群落结构的影响，以马来西亚1号菠萝蜜嫁接苗为试验材料，设置CK（不施肥）、100CF（100%化肥）、30OM（30%有机肥+70%化肥）、50OM（50%有机肥+50%化肥）、70OM（70%有机肥+30%化肥）、100OM（100%有机肥）6个处理，比较不同施肥方式下菠萝蜜幼苗生长及土壤线虫群落的差异。结果表明：与不施肥和纯施化肥相比，有机-无机配施显著促进菠萝蜜幼苗生物量积累，增加土壤pH、有机质含量。其中食微线虫和杂食/捕食线虫的占比随着有机肥用量的增加呈增长趋势，而植食性线虫占比呈下降趋势。增施有机肥能显著提高土壤线虫多样性指数（H"）和均匀度指数（J"），土壤食物网以细菌主导的分解途径占更大比例。β多样性分析结果表明，除50OM和100CF处理构建的线虫群落结构相似外，其他处理的线虫群落结构差异显著。菠萝蜜幼苗地上部干重与土壤食细菌线虫丰度、有机质和pH呈显著正相关，而植食性线虫丰度与土壤pH、有机质、碱解氮含量和食微线虫丰度呈显著负相关。食细菌线虫丰度与土壤有机质和pH呈显著正相关。有机-无机配施能够提高土壤线虫多样性和均匀度，平衡不同食性线虫的占比，改善土壤养分，使土壤环境趋于健康，从而促进菠萝蜜生长。     

神农架林区海南（开＋鸟）栖息地特征初步研究

2001年5月，对神农架林区进行了实地考察，并结合林区有关工作人员近几年的观察，在海南（开 鸟）(Gorsachius magnificus)栖息和觅食活动比较频繁的4个主要地点，用全球卫星定位系统(GPS)确定各地点的方位，并对各地点的海拔高度、坡度、坡向和植被等进行考察。结果表明,神农架林区海南（开 鸟）栖息活动地有以下特点：(1)该鸟栖息地主要分布在海拔600m以下，栖息活动地类型主要有常绿落叶阔叶混交林、灌木林和灌草丛、农田等。(2)该鸟主要选择水源充足,鱼虾丰富的小河溪流以及小河旁的农田作为觅食地。     

基于GIS的生态敏感性分析研究——以深圳梧桐山风景区为例

利用ArcGIS9．3的空间分析模块对深圳梧桐山风景区的生态敏感性进行单因子分析和综合评价，以期为该区的生态规划设计和生态环境保护提供科学依据。研究结果表明：不同单因子的生态敏感性分析结果基本相同；项目区内以敏感区和高敏感区的面积最大，占总面积的89％，低敏感区占10％，不敏感区仅占1％。由此可见，项目区极易受外界干扰而发生水土流失等生态环境问题，目前应以生态保护和恢复为主，尽量减少或避免开发性的人为活动。     

土壤中拟除虫菊酯类残留农药的气相色谱测定方法研究

建立了土壤中氯氰菊酯、氰戊菊酯和溴氰菊酯的提取、净化以及毛细管气相色谱的测定方法。运用石油醚-丙酮（P／P，2：1）混合溶剂提取，用氟罗里硅土进行层析净化，60ml石油醚／乙酸乙酯（V／V，9：1）进行洗脱，电子捕获-气相色谱测定，单点外标法定量。实验表明：土样中添加0．08mgkg^-1的氯氰菊酯、氰戊菊酯和溴氰菊酯3种农药混标时，方法回收率为89．67％～90．62％，添加0．40mgkg^-1时．方法回收率为91、07％～93．02％；操作中相对标准偏差（RSD）为2．02％～3．70％，最小检出量可达1．00pg。在检测色谱精密度实验中，5次测定3种农药混标，相对标准偏差（RSD）为1．37％～2．88％。实验表明，该法具有灵敏度高、操作简便、净化效果好、重现性好等特点。     

生物有机无机复混肥对番茄产量、品质及土壤的影响

研究了不同肥料对大棚番茄及其土壤的影响。结果表明：生物有机无机复混肥对番茄产量、品质和土壤养分有重要的作用。与NPK无机复混肥、常规施肥相比，生物有机无机复混肥可使番茄产量增加7．34％～13．64％，果实可溶性糖、有机酸、维生素C、糖酸比分别提高18．2％～23．2％、8．3％～15．6％、13．2％～15．1％、9．1％～12．6％，果实中硝酸盐(NO3^-)含量下降22．9％～23．8％。土壤耕层有机质、碱解氮、速效磷、速效钾含量分别增加8．25％～10．48％、9．43％～14．71％、11．29％～15．00％、13．60％～18．34％。根际土壤中细菌、真菌、放线菌的数量依次增加45．45％～60．00％、14．29％～33．33％、44．19％～100．00％，细菌与真菌数量比值提高19．98％～37．27％。     

安徽省北部大豆根瘤菌的分离,血清学分析及田间自然结瘤调查

对安徽省北部分离的２７株快生大豆根瘤菌和３８株慢生大豆根瘤菌的血清学分析及田间自然结瘤的血清学调查表明：００５血清型系安徽北部夏大豆产区占据优势的血清型，１８组样品和再现频率为１００％；３６株分离物中２６株属００５血清型，占总分离物的７２．５％。２０４８血清型出现频率为８３．３％；在３组样品中占瘤率达４１－５１。６％。２１７血清型占瘤率普遍低于１６％。讨论了自然结瘤调查中采样地点，大豆品种和土壤类     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

Responses of native legume desert trees used for reforestation in the Sonoran Desert to plant growth-promoting microorganisms in screen house

Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria (Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation. Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured as transpiration and diffusive resistance, when these trees were cultivated without water restrictions.