野化培训大熊猫采食和人为砍伐对拐棍竹无性系种群生物量的影响

采用固定样方法和定位观察法连续测定了2003～2007年间卧龙自然保护区大熊猫野化培训圈内及其附近区域的拐棍竹无性系种群数量和生长发育特性等参数,运用收获法与非破坏性重量估测法建立了不同龄级和残桩的竹子种群和分株生物量估测模型,进而利用最佳模型计算并评估了野化培训大熊猫采食和人为砍伐对拐棍竹无性系种群生物量和植株个体生物量的影响.结果表明:在环境条件、种群密度、生长发育特征和种群生物量等基本相似的基础上,大熊猫采食和人为砍伐不仅降低实验期间的竹子生物生产力,而且影响到后期阶段实验种群的恢复与发展.大熊猫采食样方中的竹子种群生物量虽然较对照样方低,就竹笋生物量而言,约为对照的57.79%,这与野化培训圈的面积较小、竹种单一而使采食比重(67.07%)较大有关,但其各龄级植株个体生物量均能达到大熊猫的取食利用标准(仅2004年生竹除外),具有持续供给大熊猫食物资源的潜力;而人为砍伐措施与大熊猫采食相比,影响效果极为强烈,它严重降低了拐棍竹无性系的种群生物量,尤其是竹笋重量更是如此,仅为对照样方的14.69%,且植株个体鲜重远低于大熊猫的觅食条件.因此,竹笋和无性系植株的生物量是大熊猫采食标准的主要因素.     

一株嗜碱产甲烷八叠球菌的分离鉴定与系统发育分析

在15℃条件下用产甲烷菌培养基对采自四川省红原县的牦牛粪进行富集培养,采用Hungate厌氧操作技术从富集培养物中分离得到一株在8~45℃范围生长、最适生长pH为8.5的嗜碱产甲烷菌T13.该菌株革兰氏染色阳性,细胞聚集体,在液体培养基中为肉眼可见的颗粒状物,在固体培养基上菌落为淡黄色桑葚状;可利用甲醇、乙酸盐和甲胺作为唯一碳源生长;对氯霉素和庆大霉素敏感;生长pH范围为6.5~9.5;最适NaCl浓度为0~0.15 mol L-1;最适生长温度为30℃.形态和生理生化特征以及16S rDNA序列分析表明菌株T13为梅氏产甲烷八叠球菌(Methanosarcina mazei).由于该菌最适生长pH为8.5,所以初步认为菌株T13是一株梅氏产甲烷八叠球菌的新菌株.     

利用剩余污泥水解酸化液合成聚羟基脂肪酸酯的研究

以城市污水处理厂剩余污泥水解酸化产物为原料,研究了罗氏真养菌(Ralstonia eutropha)H16在水解酸化液中的生长规律和聚羟基脂肪酸酯(PHAs)积累特性,同时分析了H16对水解酸化液中各种有机酸组分的利用规律. 结果表明,以剩余污泥52℃中温水解酸化48h的水解酸化液为培养基,在HAc水解酸化液(C/N/P=100/10/1, TOC＝2881mg/L,乙酸占总有机酸含量36.1%)中,H16最先利用乙酸和正丁酸来进行自身的生长和PHAs的合成,合成的主要产物是聚羟基丁酸酯(PHB);随后开始利用丙酸和正戊酸,在此过程中聚羟基戊酸酯(PHV)的含量也逐步上升,菌体量同步增长, H16在40h左右处于平稳期,并且达到最大积累率为12.51%(占菌体干重);最后利用的是异丁酸和异戊酸,但是此时H16已经进入衰亡期,菌体量和PHAs合成率都在下降.当以HVa水解酸化液(C/N/P=100/10/1, TOC＝2358mg/L,异戊酸占总有机酸含量29.0%)为培养基时, H16在18h达到生长的峰值,24h达到PHAs合成率的最大值为32.14%(占菌体干重),PHV为PHAs的主要形式.     

NEW METHODS OF MODELING WATER AVAILABILITY FOR AGRICULTURE UNDER CLIMATE CHANGE: THE U.S. CORNBELT1

ABSTRACT: This paper reports on new methods of linking climate change scenarios with hydrologic, agricultural an water planning models to study future water availability for agriculture, an essential element of sustainability. The study is based on the integration of models of water supply and demand, and of crop growth and irrigation management. Consistent modeling assumptions, available databases, and scenario simulations are used to capture a range of possible future conditions. The linked models include WATBAL for water supply; CERES, SOYGRO, and CROPWAT for crop and irrigation modeling; and WEAP for water demand forecasting, planning and evaluation. These models are applied to the U.S. Cornbelt using forecasts of climate change, agricultural production, population and GDP growth. Results suggest that, at least in the near term, the relative abundance of water for agriculture can be maintained under climate change conditions. However, increased water demands from urban growth, increases in reservoir evaporation and increases in crop consumptive use must be accommodated by timely improvements in crop, irrigation and drainage technology, water management, and institutions. These improvements are likely to require substantial resources and expertise. In the highly irrigated basins of the region, irrigation demand greatly exceeds industrial and municipal demands. When improvements in irrigation efficiency are tested, these basins respond by reducing demand and lessening environmental stress with an improvement in system reliability, effects particularly evident under a high technology scenario. Rain-fed lands in the Cornbelt are not forced to invest in irrigation, but there is some concern about increased water-logging during the spring and consequent required increased investment in agricultural drainage. One major water region in the Cornbelt also provides a useful caveat: change will not necessarily be continuous and monotonic. Under one GCM scenario for the 2010s, the region shows a significant decrease in system reliability, while the scenario for the 2020s shows an increase.     

滚筒式高温堆肥中微生物种类数量的研究

定量地研究了城市生活垃圾高温好氧堆肥中微生物的种类和数量分离鉴定出了细菌5属20株、霉菌8属13株、放线菌1属3株、酵母菌2属2株．探明了高温好氧堆肥能杀灭绝大多数细菌,细菌和霉菌是堆肥的优势类群,芽孢杆菌和曲霉菌是优势种．     

Implementing Ecosystem Management in Public Agencies: Lessons from the U.S. Bureau of Land Management and the Forest Service

Abstract:  Ecosystem management was formally adopted over a decade ago by many U.S. natural resource agencies, including the Forest Service and the Bureau of Land Management. This approach calls for management based on stakeholder collaboration; interagency cooperation; integration of scientific, social, and economic information; preservation of ecological processes; and adaptive management. Results of previous studies indicate differences in the extent to which particular components of ecosystem management would be implemented within the U.S. Forest Service and the Bureau of Land Management and suggest a number of barriers thought to impede implementation. Drawing on survey and interview data from agency personnel and stakeholders, we compared levels of ecosystem-management implementation in the Forest Service and Bureau of Land Management and identified the most important barriers to implementation. Agency personnel perceived similarly high levels of implementation on many ecosystem-management components, whereas stakeholders perceived lower levels. Agencies were most challenged by implementation of preservation of ecological processes, adaptive management, and integration of social and economic information, whereas the most significant barriers to implementation were political, cultural, and legal.     

长期不同施肥对水稻土交换性钙、镁和有效硫、硅含量的影响

为探明合理施肥和土壤培肥的理论依据,研究了4种长期定位施肥(CK、NPK、OM30、OM60)对湖南主要水稻土交换性钙、交换性镁、有效硫、有效硅含量的影响.结果表明,长期不同施肥改变了供试水稻土中上述养分的含量.在含钙较低的黄泥田、河沙泥、红黄泥中,施肥使土壤交换性钙含量显著升高,在相同土壤中其含量高低依序为OM30,OM60,NPK;在含钙较多的青灰泥、白鳝泥、紫潮泥中,施肥使土壤交换性钙含量降低.降低幅度与施入的有机肥量呈负相关.在黄泥田、河沙泥、青灰泥、白鳝泥、紫潮泥中,施肥使交换性镁含量降低,而在红黄泥中施肥则使交换性镁含量升高.N-PK处理使含硫较高的黄泥田、青灰泥、白鳝泥、紫潮泥有效硫含量升高,使含硫较低的红黄泥有效硫含量降低;有机、无机肥配施处理(OM30、OM60)使所有试验水稻土有效硫含量升高.施用钙镁磷肥和有机肥能够提高土壤有效硅含量.     

海洋沉积物中反硝化细菌的分离鉴定及反硝化性能研究

利用良好的通气条件对反硝化细菌进行富集筛选,同时利用二苯胺试剂和Griess试剂显色反应分别检测NO₃--N的降解和NO₂--N的产生情况,并结合产气量筛选出具有良好耐氧性且反硝化性能优异的菌株. 最终从南海海域沉积物中筛选得到具有较强反硝化能力的细菌,并对目的菌株进行分子鉴定及反硝化能力测试. 结果表明,目的菌株F-8-1能较好地降解培养基中的NO₃--N和NO₂--N,产气快. 气相色谱检测发现,气体样品中的φ(N₂)非常高,接近100%,且未检测出其他氮氧化物气体. 16S rDNA序列分析表明,菌株F-8-1与假单胞菌属具有99%的序列相似性和很高的同源性.菌株F-8-1在有氧及高盐环境中生长良好.      

大气CO2浓度升高和氮肥施用对三江平原湿地小叶章生物量及根冠比的影响

利用开顶箱薰气室（open—top chamber）试验装置,研究了不施氮（NN）、施常氮（MN,5g·m^2）和施高氮（HN,15g·m^2）3个氮素水平下大气CO2浓度升高对小叶章（Calamagrostis angustifolia）生物量和根冠比的影响。结果表明,大气CO2浓度升高对小叶章生物量的影响因生长期而异。大气CO2浓度升高对小叶章地上生物量的促进作用主要表现在生长前期,拔节期和抽穗期地上生物量较正常大气CO2浓度增加12．42％～22．60％,而腊熟期和成熟期仅增加3．11％～12．97％;大气CO2浓度升高对小叶章地下生物量的促进作用在生长后期表现明显,除拔节期外,小叶章地下生物量增加17．63％～42．20％。小叶章生物量和根冠比对大气CO2浓度的响应与供N水平有关。在HN水平下,大气CO2浓度升高使小叶章生物量和根冠比明显增加,在NN条件下促进作用则不显著。小叶章根冠比明显增加主要是地下生物量显著增长引起的。     

紫花苜蓿根际氢氧化细菌的分离与鉴定

利用气体循环培养体系从陕西乾县HUP-豆科植物紫花苜蓿(Medicago sativa)根际土壤中分离获得37株细菌.菌株氧化氢能力测定结果表明,8株菌氧化氢和自养生长能力较强,初步确定为氢氧化细菌类群;根据其形态特征、培养特征和生理生化特性,鉴定为7个不同属:假单胞菌属(Pseudomonas)、邻单胞菌属(Plesiomonas)、脂肪杆菌属(Pimelobacter)、黄色杆菌属(Xanthobacter)、勒米诺氏菌属(Leminorella)、地杆菌属(Terrabacter)和稀有杆菌属(Rarobacter);其中氧化氢能力最强的优势菌株WMQ-7 16S rDNA序列(GenBank登录号为EU807744)长度为1 451bp,GC含量为53.8%,其核苷酸序列与假单胞菌属同源性高于99%,在系统发育树上位于同一分支,将WMQ-7菌株鉴定为假单胞菌属(Pseudomonas).图2表5参16