乐果降解酶产生菌的筛选及酶条件的优化

采用室内培养室验方法,从农药长期污染的土样中分离到一株铜绿假单胞菌（Ｐｓｅｕｄｏｍｏｎａｓ ａｅｒｕｇｉｎｏｓａ）Ｐ－１,该菌株可以利用乐果为唯一碳源和能源进行生长,生长的最适ｐＨ为７．０～７．５,最适温度为３０～３５℃。在组分为０．３％蛋白胨,,０．０５％牛肉膏,０．０５％乐果,０．５％ＮａＣＬ的培养基中摇床（３５℃,１５０ｔ／ｍｉｎ）培养２４ｈ,可产生最高乐果降酶活性,达到约８ｕ／ｍＬ。     

番茄内生链霉菌S5的分离及其除草活性

采用植物内生放线菌分离方法从健康番茄（Lycopersicon esculentum）根中分离纯化出58株内生放线菌，从中挑选部分代表性菌株进行代谢产物除草活性检测，发现编号为S5的菌株的代谢产物对小麦（Triticum aesfivum L．）和绿豆（Phaseolus radiatus L．）种子的发芽有强烈的抑制作用，但对发芽后的幼苗生长无明显影响。以百喜草（Paspalum notatum）和狗牙根（Cynodon dactylon）为实验对象，证明S5菌株的代谢产物的确能抑制草籽的发芽，该活性具有潜在的除草效能。经初步鉴定，S5菌株为淡紫灰链霉菌淡青变种（Streptomyces lavendulaevar．glaucescens）。发酵条件实验结果表明，S5菌株在1％葡萄糖和0．3％牛肉膏的S培养基中，以2％接种量在pH7．0和25℃摇床培养，可得到最强的抑制种子发芽的生物活性。     

番茄内生拮抗细菌的分离鉴定及培养条件研究

针对番茄生产上灰霉病和叶霉病两大瘸害,为寻找安全、高效无污染的生防菌株及其最佳培养条件,本试验采用组织分离法从健康的番茄植株中分离出642个内生细菌菌株,并采用平板对峙法筛选出对番茄灰霉病菌和叶霉病菌拮抗作用强且稳定的两个菌株Thyy1和Jcxy8。通过形态学观察及生理生化特征测定,初步鉴定Jcxy8属环状芽孢杆菌（Bacillus circulans）,菌株Thhy1属枯草芽孢杆菌（Bacillus subtilis）。内生拮抗细菌在以豆饼粉为原料的6号培养基中生长速度快,发酵滤液对两种病原菌的抑制作用强。培养基初始pH值、培养时间、温度、通气量等对菌株生长及其抗菌物质的分泌有明显影响。以豆饼粉培养基、初始pH6．7、培养时问48h、温度30qc、并尽量增大培养通气量为菌株的最佳培养条件。     

胶质芽胞杆菌及其突变株生理特性的初步研究

本文对经过筛选培育出的分解硅酸盐能力较强的胶质芽胞杆菌突变株UV09K及抗高浊`恩赐乔石工力朱PHt10K的生理特性进行了研究。其中，最佳氮源为麦麸汁，民出发菌株相比，分解硅酸盐能力分别提高164％、12．7％。最佳碳源为葡萄糖、与出发菌株相比，产酸能力分别提高260％、155％，金属离子培养温度、PH，气／液比等对突变株的生长有一定影响。其结果可作为选定工作化条件的参考。     

两株根际真菌的耐盐、溶磷、促生效果及其分类鉴定

[目的]分离筛选耐盐溶磷真菌用于改良低产盐碱土壤意义重大.[方法]利用PVK固体培养基培养、以透明圈法从黄河三角洲地区盐生植物和农作物根际土壤中筛选出溶磷真菌15株,用不同NaCl浓度的PDA培养基培养、用液体摇床培养测定耐盐性和溶解Ca3(P04)2能力;结果编号为F2、F19的2菌株最高可耐受盐浓度分别达到7％和9...     

一株产生氨氮和亚硝酸盐氮菌的筛选鉴定及特性研究

从4个草鱼池塘中分离和定性筛选获得29株能够产生氨氮和亚硝酸盐氮的菌株。通过对编号为C95的菌株进行菌落形态学观察和16S rDNA序列分析,表明该菌株为革兰氏阴性杆状菌,与寡养单胞菌属（Stenotrophomonas sp.）的同源性达98%。采用单因素多水平试验对菌株的产氨氮和产亚硝酸盐氮特性进行研究发现：（1）氮源、碳源、温度和摇床转速都能显著影响菌株的生长及产生氨氮和亚硝酸盐氮的含量,但pH（5～9）对其无显著影响（P〉0.05）;（2）该菌株生长及产生氨氮和亚硝酸盐氮最适宜的培养基以及培养条件为：LB、pH 5～9、25℃、150 r.min-1。由C95作为指示菌株筛选得到SC01、SC07两株（2/33）去除氨氮和亚硝酸盐氮效果较好的菌株。因此,C95可作为筛选具有降氨氮和亚硝酸盐氮功能的有益菌的指示菌株。     

红壤中产吲哚乙酸并具解磷作用的促生菌筛选鉴定及促生效果研究

从江西红壤花生地中,筛选出3株产吲哚乙酸(IAA)菌株,其中ZH5菌株具有较强分泌IAA的能力且性能稳定,培养24 h时IAA产量达到43.18μg/ml,且菌株ZH5具有较强的解磷能力。通过菌株形态、生理生化特征测定及16S r RNA的保守序列鉴定,初步确定菌株ZH5为巨大芽孢杆菌(Bacillus megaterium)。对菌株生长和发酵条件进行研究,结果表明促进菌株ZH5生长和增强分泌IAA的最佳培养条件基本一致,最佳培养条件初始p H为6~8,最佳通气量为50 ml/250 ml,30℃摇床培养24 h;最佳碳源和氮源分别是蔗糖和酵母粉。在实验室中进行盆栽试验,结果表明用ZH5菌株处理的花生株高增加了54.0%;植株鲜重增加了49.8%;并且ZH5菌株处理的花生植株全磷及花生根长、根尖数、根表面积及根体积均有显著增加,分别增加了21.84%、64.20%、28.20%、34.35%和68.67%。该研究结果为菌株ZH5在农业生产中的应用提供了理论依据和实验基础。     

一株从金钱树上分离的产纤维素降解酶的菌株的分离及特性鉴定

本研究从金钱树（Zamioculcas zamiifolia）白绢病（Southern blight）病株上分离到一株产纤维素酶菌株SM,经形态观察和rDNA—ITS序列分析鉴定为齐整小核菌（Sclerotium rolfsii Sacc）,经以羧甲基纤维素钠为唯一碳源的培养基培养和刚果红染色测定,证明SM菌株可产生高活性纤维素降解酶。本文对SM菌株产纤维素降解酶的液态发酵条件进行了研究,结果表明：在起始pH6．0,无机氮：有机氮：纤维素碳源之比为0．07g：1．4g：1．6g,温度为30℃,摇床转速为160r／min,发酵培养时间为5d的条件下,该菌株发酵液的CMC酶活性达到11．7U／mL,滤纸酶活性达到2．156U／mL,β-葡萄糖苷酶活性达到3．911U／mL。     

土壤耐硒菌株筛选及其硒活化能力评价研究

  目的  从湖北省恩施市双河镇新塘乡渔塘坝硒矿床采集矿渣、淤泥、农田土壤,从中筛选分离出耐硒菌株,并对筛选出菌株的活化土壤硒的能力进行评价。  方法  采用稀释涂布平板法和平板划线法分离、筛选出耐受亚硒酸钠浓度较高的菌株,根据菌株形态学特征和用分子生物学方法对其进行分类鉴定,再将分离得到的耐硒菌株分别接种于酸性富硒赤红壤中进行培养,通过测定培养后土壤中的硒含量评价两菌株活化土壤硒的能力。  结果  筛选出了细菌B-1和真菌B-2两耐硒菌株;细菌B-1被鉴定为嗜麦芽寡养单胞菌（Stenotrophomonas maltophilia）,其可耐亚硒酸钠浓度为17000 μg mL?1,在温度20 ~ 35 ℃、pH 5 ~ 9、盐浓度0 ~ 3%条件下可正常生长;真菌B-2被鉴定为聚多曲霉（Aspergillus sydowii）,该菌株可耐亚硒酸钠浓度为6000 μg mL?1,在温度25 ~ 30 ℃、pH 4 ~ 7、盐浓度2% ~ 5%条件下可正常生长。添加两耐硒菌株培养后土壤的可溶态硒和可交换态硒含量均显著提高。  结论  筛选出具有较高的硒耐受性和较强的活化酸性富硒土壤中硒的能力的菌株,可为富硒土壤资源开发利用提供生物种质资源和技术手段,对富硒微生物肥料研发、富硒农产品生产和硒污染土壤环境修复也有重要意义。     

利用小孢子胚离体培养筛选抗除草剂的油菜

选用4个甘蓝型油菜（Brassica napus L．）F、（7039，7040，282和5102）为小孢子培养供体材料，分别对小孢子胚在含草甘膦和盖草能的培养基上进行培养，以筛选出抗草甘膦和抗盖草能的胚状体，进而获得再生植株。其中，基因型7039和7040用于草甘膦筛选，282和5102用于盖草能的筛选。选取子叶期胚状体，在含0．006％的草甘膦及0．01％和0．02％盖草能的MS-2培养基上培养2周，不抗草甘膦和小抗盖草能的胚状体2周内变褐死去，抗草甘膦和抗盖草能的胚状体转绿。随后转绿胚状体转移至正常MS-2培养基中继续培养，直至获得再生植株。再生植株喷施0．25％的草甘膦液表明均抗草甘膦；而对植株喷施0．05％的盖草能液时，0．02％筛选出的植株大部分为抗盖草能，而0．01％筛选出的植株却大部分死去，表明用0．02％浓度筛选抗盖草能植株的方法更有效。用170mg／L秋水仙碱直接处理再生植株20和30h，染色体加倍率分别达到了34％和52％。     

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。     

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.     

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.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

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,     

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,     

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,     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

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.