干巴菌菌丝营养生理特性的初步研究

本文报道了不同碳源、氮源、微量元素及维生素培养基对干巴菌菌丝生长的影响。试验表明,干巴菌菌丝利用最好的的碳源是葡萄糖,其次是蔗糖。利用最好的氮源是硝酸钙,其次是硝酸铵和硫酸铵,对蛋白胨和尿素的利用效果差。缺少碳源或氮源时,菌丝生长细弱、稀少,不形成原基。微量元素和维生素均对干巴菌菌丝生长有促进作用,其中以锰、铜和维生素Ｂ２的作用尤为突出。     

林芝松口蘑抗肿瘤组分的筛选

为筛选林芝松口蘑(Tricholoma matsutake)子实体中具抗肿瘤作用的组分,采用MTT法测定林芝松口蘑乙醇提取物的不同有机溶剂萃取分部对乳腺癌细胞(MCF-7)、胃癌细胞(SGC-7901)和肺癌细胞(A549)的体外抑制率。结果表明:林芝松口蘑乙醇提取物的抑癌活性物质主要集中在氯仿分部,100μg/mL作用48h,对MCF-7和SGC-7901的抑制率分别达到了64%和55%;乙醇提取物的各萃取分部对A549抑制效果较差,在实验浓度范围内抑制率均未超过25%。     

郁金香种球冷藏与花期调控

以郁金香阿波罗、金阿波罗两个品种的自繁种球为材料,探讨了它们在贮藏中的花芽分化、冷处理长短与花期调节的关系。在上海气候条件下,郁金香从6月底开始叶芽分化,到8月初花芽分化基本完成;之后对郁金香种球进行冷处理表明,冷处理时间越长,开花越早,花茎越高;生理生化分析表明,随着冷处理的进行,种球鳞片中的POD活性逐渐降低、花芽中的POD活性逐渐升高,并出现新的蛋白带。     

Environmental persistence of 2,3,7,8-tetrachlorodibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxin in soil around hardstand 7 at eglin air force base,Florida

Background and Goal  A number of global events have generated intense scientific scrutiny and public concern of polychlorinated dibenzo-p-dioxins (dioxin). DIoxins have been associated with a range of adverse health effects. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is recognized as among the most dangerous of the dioxin compounds, and was a contaminant found In one of the herbicides used for vegetation control during the Vietnam conflict: Agent Orange. As a result of purging spray systems and leaking drums of Agent Orange concentrate, TCDD contamination occurred in the soils surrounding Hardstand 7 at Eglin Air Force Base, Florida. This research uses a multimedia model to estimate the TCDD concentrations in surface soil around Hardstand 7 for a 70-year time Interval beginning with observed surface soil concentrations 1984. Methods  Hardstand 7 is a nearly 40-m circular concrete and asphalt aircraft parking area. The hardstand was used as a staging area for spraying equipment used to disseminate herbicide In a test area called C-52A within EAFB. Concentrated herbicide was also stored in 208-L barrels for use with the equipment, and later, for disposal. In 1984, a field investigation characterized the extent of TCDD contamination in surface soils around Hardstand 7 using a radial sampling protocol. The 1984 observed concentrations and locations was used in a multimedia model, CalTOX, as an initial source term concentrations and locations to estimate expected concentrations during the subsequent 70-years. Results  The results indicate that more than 94% of the TCDD observed in surface soils 1984 will remain after a 70-year period. Access restrictions and remediation activities at the site eliminate bar verification of the CalTOX estimates. Conclusions. TCDD is highly persistent in the soil medium and natural attenuation may not produce a significant decrease In soil concentrations. Recommendation  Active remediation actions may be required to prevent exposure to TCDD contamination surface soils. Verifying CalTOX concentration estimates an Important step that should be performed, however, the, model provides an easy to use tool to estimate TCDD surface soil contamination at herbicide storage or dispersion staging sites.     

Short- and long-term effects of heavy metals on phosphatase activity in soils: An ecological dose-response model approach

Summary The aim of this study was to provide manageable data to help establish permissible limits for the pollution of soil by heavy metals. Therefore the short-and long-term effects of heavy metal pollution on phosphatase activity was studied in five different soil types. The results are presented graphically as logistic dose-response curves. It was possible to construct a curve for sand and silty loam soil but it was more difficult to establish a curve for sandy loam and clay soil and nearly impossible (except for Cu) for peat. The toxicity of the various metals can be compared on the basis of mmol values. In clay soils, for Cd, Cr, Cu, and Zn, the 50% effective ecological dose (ED₅₀) values were comparable (approximately 45 mmol kg^–1), but the ED₁₀ values were very different, at 7.4, 41.4, 15.1, and 0.55, respectively. At the ED₅₀ value, toxicity did not decrease with time and, in sandy soils, was approximately 2.6 mmol kg ^–1 dry soil for Cd, Cu, and Zn. In four out of five soils, the Cd toxicity was higher 1.5 years after the addition of heavy metal salts than after 6 weeks. Toxicity was least in the sandy loam, silty loam, and clay soil, and varied in general between 12 and 88 mmol kg^–1. In setting limits, the criteria selected (no-effect level, ED₁₀ or ED₅₀) determine the concentration and also the toxicity of the sequence. It is suggested that the data presented here could be very useful in helping to set permissible limits for heavy metal soil pollution.     

Arbuscular mycorrhizae in a long-term field trial comparing low-input (organic, biological) and high-input (conventional) farming systems in a crop rotation

 Arbuscular mycorrhizal (AM) root colonization was studied in a long-term field trial in which four farming systems currently in use in Switzerland were continuously applied to a randomized set of plots at a single field site from 1978 till 1993. There were two low-input farming systems (organic and bio-dynamic) and two high-input (conventional) farming systems (according to Swiss guidelines of integrated plant production with and without farmyard manure). The systems had an identical 7-year crop rotation and tillage scheme and differed essentially only in the amount and type of fertilizer supplied and in plant protection management. The percentage of root colonization by AM fungi was determined in field samples 2–3 times over the growing season in crops in the rotation, namely in winter wheat (Triticum aestivum L. cv. Sardona), vetch-rye and grass-clover. We found the percentage of root length colonized by AM fungi to be 30–60% higher (P≤0.05) in the plants grown in soils from the low-input farming systems than in those grown in conventionally farmed soils. Approximately 50% of the variation of AM root colonization was explained by chemical properties of the soils (pH, soluble P and K, exchangeable Mg), the effect of soluble soil P being most pronounced. The potential of the field soils from the differently managed plots to cause symbiosis with AM fungi was tested in a glasshouse experiment, using wheat as a host plant. Soils from the low-input farming systems had a greatly enhanced capacity to initiate AM symbiosis. The relative differences in this capacity remained similar when propagules of the AM fungus Glomus mosseae were experimentally added to the soils, although overall root colonization by AM fungi was 2.8 times higher. Received: 27 August 1999     

外源NO对Ca(NO3)2胁迫下黄瓜幼苗生长和抗氧化系统的影响

本研究以黄瓜为试材,采用营养液水培,研究了外源NO对Ca(NO3)2胁迫下黄瓜幼苗生长和抗氧化酶系的影响.结果显示,在70mmol·L-1的Ca(NO3)2胁迫下,植株生长受到抑制,干重和叶绿素含量显著下降,叶片和根系抗氧化酶SOD、POD、CAT和APX活性均升高,膜脂过氧化产物MDA及可溶性 蛋白含量增加.而叶面喷施NO供体SNP显著缓解了Ca(NO3)2胁迫对黄瓜幼苗生长的抑制,植株干重显著增加.同时,抗氧化酶活性、可溶性蛋白和叶绿素含量也有不同程度的上升,MDA含量显著下降.以上表明,NO能够增强黄瓜幼苗对Ca(NO3)2胁迫的耐性.喷施SNP对正常营养液培养的黄瓜幼苗无显著影响.     

Availability of soil boron fractions to M.26 apple rootstock

The availability of various boron (B) fractions in soil to M.26 apple (Malus spp.) rootstock was examined. The study was carried out in a greenhouse on soils with diverse chemical and physical properties. The following B fractions were determined: (i) B in soil solution, (ii) B non‐specifically adsorbed on soil surface, (iii) B specifically adsorbed on soil colloid surfaces, (iv) B occluded in Mn oxyhydroxides, (v) B occluded in noncrystalline aluminum (Al) and iron (Fe) oxides, (vi) B occluded in crystalline Al and Fe oxides, (vii) B fixed with soil silicates, and (viii) total soil B. In the studied soils there were: 0.07–0.17 mg kg^‐1 B in soil solution, 0.01–0.03 mg kg^‐1 B non‐specifically adsorbed on soil surface, 0.04–0.08 mg kg^‐1 B specifically adsorbed on soil colloid surfaces, 0.28–0.67 mg kg^‐1 B occluded in manganese (Mn) oxides, 4.03–17.22 mg kg^‐1 B occluded in noncrystalline Al and Fe oxides, 8.93–50.62 mg kg^‐1 B occluded in crystalline Al and Fe oxides, 12.2–42.5 mg kg^‐1 B fixed with soil silicate, and 52.9–82.2 mg kg^‐1 total B. Simple correlation analysis showed positive correlation between B contents in M.26 apple rootstocks and amounts of B in soil solution (r=0.77), B non‐specifically adsorbed on soil colloid surfaces (r=0.65), B specifically adsorbed on soil surface (r=0.76) and B occluded in Mn oxyhydroxides (r=0.77). No relation was found between plant B contents and amounts of B occluded in non‐crystalline and crystalline Al and Fe oxides, B fixed with soil silicates and total B. The results indicated that extraction of B by 0.1 M NH₂OH HCl solution adequately represented amounts of B in soil solution, B non‐specifically and specifically adsorbed on soil compound surfaces and B occluded in Mn oxyhydroxides to assess availability of B to apple trees.     

土壤中水溶性有机质的结构特征及其与富里酸、胡敏酸的比较

采用元素分析、1HNMR和FTIR研究了黄泥土中水溶性有机质组成及结构特征,并与富里酸、胡敏酸进行比较。结果表明:胡敏酸含有大量的芳香族不饱和物质,烷基链烃多,支链长;富里酸以含有大量的羧基为主要结构特征;水溶性有机质主要由碳水化合物组成,含有大量的羟基,芳香族不饱和物质少。     

三峡库区不同农业经营模式的肥料投入评估及其变化特征

农村生态环境在农村发展中的地位日益突出,研究农业生产转型过程中不同农业经营模式农资投入对解析农村生态环境中非点源污染负荷有重要启示,同样有助于针对性地制定控制面源污染的方案。采用PRA(Participatory Rural Appraisal)方法,抽样采集三峡库区重庆段农业经营主要农作物肥料投入情况,根据整理调研材料、综合评估调研结果划分研究区农业生产经营模式为:一般散户、种植大户、公司企业、养殖大户、种养大户、合作社。核算不同经营模式单位面积肥料投入,确定研究区不同经营模式下用肥量与结构的变化特征。研究结果表明:1)研究区肥料用量总量在1997年到2011年间呈递增趋势,复合肥近年增速明显;2)不同经营模式用肥结构间存在差异,一般散户、养殖大户、种养大户这3种经营模式与种植大户、公司企业、合作社这3种经营模式各自内部又存在相似性,前者常规用肥比例较大,而后者在有机肥、高钾复合肥等肥料的用量及比例方面较高;3)研究区用肥结构以常规肥料为主,其中氮、磷折纯量单位面积投入为一般散户、养殖大户较种植大户、公司企业、养殖大户、种养大户、合作社显著高;4)农户种植结构因经营模式而异,一般散户、养殖大户、种养大户以传统的农作物玉米、水稻、红苕、土豆为主,表现为"小而全"的特性;而种植大户、公司企业、合作社则在技术支撑的前提下表现为以市场为导向、生产特定高附加值农产品。三峡库区重庆段不同农业经营模式中主要农作物单位面积用肥折纯量大小为玉米蔬菜土豆其他作物红苕果木园林水稻。