手性三唑类杀菌剂氟环唑对土壤微生物的立体选择性影响

为了研究土壤微生物对手性三唑类杀菌剂氟环唑的立体选择性响应,通过非靶向代谢组学和高通量测序联合技术探究了土壤代谢组和微生物群落对氟环唑外消旋体及对映体的响应机制。结果表明：氟环唑及其对映体处理4周后,土壤中氟环唑降解不显著,其残留能够引起土壤代谢组和土壤微生物群落组成的显著变化。土壤代谢组、细菌和真菌群落组成、PICRUSt基因功能预测的代谢途径均表现出由2R,3S-（+）-氟环唑驱动的立体选择性响应。PICRUSt基因预测表明,细菌中被显著影响的MetaCyc通路有10条,真菌中比对出22条。氟环唑外消旋体和（+）-对映体比（-）-对映体表现出对土壤微生物更显著的干扰作用（P<0.05）。氟环唑暴露引起了土壤环境中细菌和真菌群落、代谢、基因功能预测通路不同程度的立体选择性响应。鉴于土壤环境在农业生产中的重要性,土壤微生物组和代谢组的表征可以为暴露于手性三唑类农药顺式氟环唑及其对映体所带来的生态风险提供新的见解。     

防治六月红芋疫病的药剂筛选试验

进行80％烯酰吗啉WG、72％霜疫力克WP、75％百菌清WP、80％代森锰锌WP防治六月红芋疫病的药效筛选试验,结果表明:80％烯酰吗啉WG 2 000倍液、72％霜疫力克WP600倍液的防效较好,分别达84.68％和81.22％.     

Evidence for magnetospheric effects on the sodium atmosphere of mercury

Monochromatic images of Mercury at the sodium D(2) emission line showed excess sodium emission in localized regions at high northern and southern latitudes and day-to-day global variations in the distribution of sodium emission. These phenomena support the suggestion that magnetospheric effects could be the cause. Sputtering of surface minerals could produce sodium vapor in polar regions during magnetic substorms, when magnetospheric ions directly impact the surface. Another important process may be the transport of sodium ions along magnetic field lines toward polar regions, where they impact directly on the surface of Mercury and are neutralized to regenerate neutral sodium atoms. Day-to-day variations in planetary sodium distributions could result from changing solar activity, which can change the magnetosphere in time scales of a few hours. Observations of the sodium exosphere may provide a tool for remote monitoring of the magnetosphere of Mercury.     

Ethyl mercury p-toluene sulfonanilide: lethal and reproductive effects on pheasants

Ethyl mercury p-toluene sulfonanilide (active ingredient of Ceresan M) at a dietary concentration of 30 parts per million (12.5 parts of mercury per million) was lethal to adult ring-necked pheasants. Egg production and survival of third-week embryos were sharply reduced when breeders were maintained on feed containing 10 parts of this compound per million (4.2 parts of mercury per million).     

藻源溶解性有机质对汞甲基化的影响

  目的  探究藻源溶解性有机质(DOM)各亚组分在不同腐解时间、不同汞(Hg2+)质量浓度下对水体中汞甲基化的影响。  方法  应用树脂串联技术分离藻体DOM的6种亚组分,利用室内培养方式进行Hg2+的甲基化试验。  结果  藻类DOM主要由羟基、烃基和芳环C=C等官能团组成;未经腐解的DOM各亚组分中,疏水性有机组分对汞甲基化的影响高于亲水性有机组分;随腐解时间延长,DOM官能团逐渐减少,疏水性有机组分对汞甲基化的影响表现为先降低后升高;亲水性有机组分抑制汞甲基化。  结论  DOM相对含量的升高抑制了汞的甲基化,DOM降解后,释放出来的Hg2+被微生物重新利用,甲基化程度加剧。图3参24     

CAD在高职"园林制图"中的步骤及细节问题

本文通过近两年的园林制图教学，针对高职生的特点，总结出园林AUTOCAD制图的常规制图流程及细节问题，能够使园林专业的高职生很快对园林AUTOCAD熟练上手。     

"Dream deprivation": effects on dream content

Dream content elicited following the selective deprivation of rapid-eye-movement sleep was intensified compared to that elicited under nondeprivation conditions. This effect was observed both for repressers and for sensitizers, but was significant only for repressers. On nondeprivation nights, the dream periods of sensitizers were shorter and their dreams more intense than those of repressers.     

有机生态肥在西瓜生产上的应用效果研究

以长效有机生态肥与4种化学复合肥在西瓜上进行肥效试验，结果表明，有机生态肥比化学复合肥每公顷增产3000kg以上，纯增收1500元以上，还能改善西瓜品质，防止西瓜早衰，增强抗病性，可在西瓜生产上大面积推广应用。     

富士苹果贮藏期间果肉褐变的生化特性研究

比较了 0 ,4℃和 CO2 >4 0 m L/L,CO2 <4 0 m L/L 组合贮藏条件对富士苹果果肉褐变的影响 ,并以普通冷藏为对照 ,探讨了富士苹果果肉褐变的生化特性。结果表明 ,CO2 >4 0 m L/L 容易导致果肉褐变 ,果肉褐变后多酚氧化酶 (PPO)活性、丙二醛 (MDA)含量和相对电导率均呈上升趋势 ,超氧化物歧化酶 (SOD)活性和单宁含量呈下降趋势     

Comment on "Early domesticated fig in the Jordan Valley"

Kislev et al. (Reports, 2 June 2006, p. 1372) described Neolithic parthenocarpic fig fruits and proposed that they derive from trees propagated only by cuttings and thus represent the first domesticated plant of the Neolithic Revolution. Because parthenocarpic fig trees naturally produce both seeded and seedless fruits and are capable of spontaneous reproduction, we argue that the finds do not necessarily indicate cultivation, nor horticulture predating grain crops.     

“鸡-玉米-小麦”有机模式与“玉米-小麦”常规模式生产力之比较研究:以弘毅生态农场为例

本研究以山东省平邑县弘毅生态农场为例,通过货币及能值分析,以1年为周期,比较"鸡-玉米-小麦"有机模式与"玉米-小麦"常规模式生产力差异。结果表明:有机模式净货币收入为常规模式的3.8倍,2种模式投入产出比分别为1∶2.3和1∶1.8;系统能值投入表现为:有机模式为常规模式的22.8%,化肥占常规模式能值投入的91.32%,成为其成本过高的主要原因;有机模式能值产出和系统产出率分别为常规模式的1.7倍和7.5倍。投入相同量的能值,有机模式比常规模式产生更多的支持与服务功能,表现出"低投入、高产出"农业特点。     

丰果素在枣树上的应用效果研究

对丰果素在枣树上的应用效果进行了研究，结果表明，在果树的初花期和幼果期分别喷施50g／667m^2“丰果素”，可增加枣的坐果率和单果质量，比对照分别提高4．0％和7．5％，从而极显著地提高产枣量。     

有机肥发酵剂应用效果的研究 Ⅱ.有机肥发酵剂对有机物料发酝效果的研究

在选择有机肥发酵剂的高效菌株组合及研制有机肥发酵剂的工艺流程的基础上，利用有机肥发酵剂对有机肥及有机物料进行发酵，以自然发酵为对照，明确了有机肥发酵剂对有机肥及有机物料分解的效果。与国外同类产品相比，有机肥发酵剂对高纤维有机物料的发酵效果好于EM，对蛋白质类有机物料的发酵效果与EM相近。同时明确了有机物料接种有机肥发酵剂的操作技术。     

抗生素在有机肥料-土壤-农作物系统中的转化及影响的研究进展

综述了国内外对抗生素在“有机肥-土壤-农作物”系统中的转化及其影响的研究状况,旨在为降低抗生素危害提供参考.国内外研究表明:规模养殖场产生的畜禽粪便作为有机肥料施入农田土壤前,无害化处理过程需考虑抗生素降解效果,否则存在抗生素进入食物链的潜在风险;土壤微生物、土壤酶活性会受到有机肥料中残留抗生素的影响,间接影响土壤肥力;部分农作物在生长发育过程中受残留抗生素的影响,且会吸收抗生素,使抗生素在食物链中迁移累积,给人类健康带来不可预知的威胁.     

有机酸类化感物质对甜瓜的化感效应

以甜瓜种质"新银辉"为材料,用苹果酸、柠檬酸、对羟基苯甲酸、肉桂酸、阿魏酸、水杨酸和香豆酸等7种有机酸类化感物质处理甜瓜种子和幼苗,探讨其对甜瓜的化感效应及作用机理。结果表明:苹果酸可以促进甜瓜种子发芽和幼苗胚根生长,抑制植株鲜重增加和胚轴生长;柠檬酸促进发芽,对羟基苯甲酸和肉桂酸抑制发芽,但三者均抑制胚根生长,且对鲜重和胚轴生长表现为低促高抑效应,高浓度肉桂酸对种子发芽和胚轴生长的抑制效应最强,可能是甜瓜重要的化感物质;阿魏酸和香豆酸对发芽表现为低促高抑效应,抑制鲜重、胚根和胚轴生长;水杨酸对发芽和胚轴生长表现为低促高抑效应、抑制鲜重和胚根生长。7种有机酸处理后过氧化物酶活性均增强,有机酸类物质对甜瓜的化感效应可能和其体内的过氧化氢水平有较高的相关性;苹果酸、肉桂酸、对羟基苯甲酸和水杨酸处理后甜瓜幼苗体内超氧化物歧化酶的活性基本呈下降趋势,柠檬酸、阿魏酸和香豆酸则表现为低促高抑效应;过氧化物酶活性变化较复杂,但基本随处理浓度升高而上升;丙二醛含量大多低于对照。     

不同菌剂在有机废弃物堆酵中的应用初探

采用草皮、药渣及菇渣等3种有机废弃物作为有机肥堆酵原料,加入神采生物菌剂、农家肥发酵液、VT-1000菌剂、金宝贝生物菌剂、三真生物菌剂等5种菌剂进行堆酵试验,结果表明:堆酵有机肥时,需根据有机材料本身的质地选取相适应的菌剂,含氮量较高有机废弃物宜选用VT-1000菌剂,含磷、钾较高的有机废弃物则宜选用三真生物菌剂。     

Comment on "Physical model for the decay and preservation of marine organic carbon"

Rothman and Forney (Reports, 1 June 2007, p. 1325) described a model for the decay of marine organic carbon. However, the enzyme deactivation rates required by their model are too fast compared with available data, and the model fails to explain the similarity in observed decay rate constants from different experiments. Alternative models provide equally good fit to the observed temporal trend in decay rate constants.     

Participatory organic certification in Mexico: an alternative approach to maintaining the integrity of the organic label

Over the past two decades the growth of the organic sector has been accompanied by a shift away from first party, or peer review, systems of certification and towards third party certification, in which a disinterested party is responsible for the development of organic standards and the verification of producer compliance. This paper explores some of the limitations of the third party certification model and presents the case of Mexico as an example of how an alternative form of participatory certification has emerged. The paper suggests that participatory guarantee systems (PGS) are reflective of the growing “beyond organic” movement, which focuses on reconstructing the local and re-embedding food systems into their socio-ecological contexts. It argues that PGS offers a number of benefits for producers and consumers, particularly in the South, but that it faces a number of challenges as well, such as a lack of formal recognition, social conflicts and dependence on donated resources.     

Taming of a poison: biosynthesis of the NiFe-hydrogenase cyanide ligands

NiFe-hydrogenases have an Ni-Fe site in which the iron has one CO and two CN groups as ligands. Synthesis of the CN ligands requires the activity of two hydrogenase maturation proteins: HypF and HypE. HypF is a carbamoyltransferase that transfers the carbamoyl moiety of carbamoyladenylate to the COOH-terminal cysteine of HypE and thus forms an enzyme-thiocarbamate. HypE dehydrates the S-carbamoyl moiety in an adenosine triphosphate-dependent process to yield the enzyme thiocyanate. Chemical model reactions corroborate the feasibility of this unprecedented biosynthetic route and show that thiocyanates can donate CN to iron. This finding underscores a striking parallel between biochemistry and organometallic chemistry in the formation of an iron-cyano complex.