不同施肥处理对马铃薯农田土壤理化性状及产量的影响

为了探究不同施肥处理对马铃薯农田土壤理化性状及产量的影响,试验地采用马铃薯连作模式,设置3个施肥处理,即：单施化肥(T)、有机肥配施化肥(YTF 1/2)、全量有机肥(YTF)。结果表明：在不同施肥处理下马铃薯农田土壤的理化性质和马铃薯产量发生了变化,其中变化最为明显的土壤指标有土壤容重、孔隙度、饱和导水率、有效磷。YTF处理较T处理可分别显著(P<0.05)降低土壤容重16.8%,增加土壤孔隙度12.7%,提升饱和导水率25.3%。YTF处理可显著提升土壤有效磷含量43.0%,但各处理间土壤pH、有机碳、全氮、全磷、碱解氮、速效钾之间差异并未达到显著水平。同时,较之T处理,YTF处理亦可显著提升土壤团聚体含量。YTF和YTF 1/2处理可分别较T处理提升马铃薯产量24.6%和12.8%。因此,施用有机肥不仅可以改善土壤结构,改良土壤物理性状,亦能促产增收。     

Effect of Heat Stress on Grain Growth, Starch Synthesis and Protein Synthesis in Grains of Wheat (Triticum aestivum L.) Varieties Differing in Grain Weight Stability

The effect of heat stress on the components of grain weight was analysed in wheat ( Triticum aestivum L.) varieties differing in grain weight stability. The wheat varieties PBW154, Sonalika and Hindi62 were raised in the field (New Delhi, India; 77°12' E, 28°40' N, 228.6 m a.s.l.) at three dates of sowing: 19 November 1992 (DOS I), 14 December 1992 (DOS II) and 18 January 1993 (DOS III). The late-sown crop (DOS III) experienced 6–8 °C warmer temperatures during grain development than the crop sown at the normal time (DOS I). The heat susceptibility index (S) revealed that grain weight was less susceptible to heat in Sonalika and PBW154 than in Hindi62. Heat stress reduced both the grain growth duration (GGD) and the grain growth rate (GGR). The grain weight reduction in PBW154 and Sonalika was mainly due to a reduction in GGR, while that of Hindi62 was due to a reduction in GGD. In vivo studies on starch and protein synthesis in excised endosperm at 15, 25 and 35 °C revealed that both processes were more thermotolerant in Hindi62 than in PBW154. The grain starch content was stable in Hindi62 while that in PBW154 was significantly reduced under heat stress. The grain nitrogen content at maturity increased in both varieties under heat stress. It was concluded that the heat susceptibility of grain weight in Hindi62 was mainly due to a reduction in GGD, although GGR, starch and protein synthesis were more thermotolerant in developing grains of Hindi62 than in those of PBW154.     

柞蚕肠液理化性质与饲料效率的相关性研究

对柞蚕肠液的理化性质与饲料效率的相关性进行研究的结果表明 :柞蚕肠液对促进蚕体抗病与消化吸收功能有着重要作用 ,平均每头蚕有肠液 1 76mL ,品种间开差为 0 78mL ,相对开差 5 7 80 % ,肠液量越多 ,饲料效率越高 ;柞蚕不同品种肠液pH平均值未发现明显差异 ,但强健好养饲料效率高的品种个体间开差小 ;柞蚕肠液缓冲力除与品种强健性有关外 ,还与品种的饲料效率呈正相关 ,在强健丰产与高饲料效率品种中 ,肠液恢复pH原值所需时间越短 ,饲料效率越高 ,电刺法取出肠液后 ,肠液恢复缓冲力所需时间是恢复其pH原值时间的 1 8倍多 ,同恢复肠液pH原值所需时间长短与品种强健性和饲料效率的关系完全一致。     

提高中锰白口铸铁韧性的研究

为改善中锰白口铸铁的韧性以扩大其应用范围,本文探讨了C, Si, Mn等合金元素、变质处理和热处理工艺对中Mn白口铸铁组织和性能的影响.     

Biosynthesis of Depsipeptide Mycotoxins in Fusarium

The cyclic hexadepsipeptide enniatin is known as a phytopathogenic compound from Fusaria causing necrosis and wilt. The molecule consists of three alternating residues each of a branched chain amino acid and D-hydroxyisovaleric acid (D-Hiv). Enniatins are synthesized by a 347kDa multienzyme (enniatin synthetase) via a thiol template mechanism. The corresponding gene esyn1 has an open reading frame of 9393 nucleotides and harbours two modules, one responsible for D-hydroxy acid activation and one for L-amino acid activation with an integrated N-methyltransferase domain. Such methyltransferases build an homologous group among N-methyl peptide synthetases. Enniatins are synthesized by step-wise condensation of dipeptidol building blocks in an iterative manner resembling fatty acid synthesis. A key enzyme in enniatin biosynthesis is the NADPH-dependent D-2-hydroxyisovalerate dehydrogenase, that supplies enniatin synthetase with D-Hiv. Enniatins contribute to the wilt toxic character of Fusaria. Virulence was significantly reduced in F. avenaceum after disruption of the esyn1 gene.     

Influence of the physical and chemical properties of soil on the retention process of isoxaflutole and its two main derivatives

Isoxaflutole is a new pre‐emergence herbicide for use in maize and sugarcane. Its two main derivatives are a diketonitrile derivative, the 2‐cyano‐3‐cyclopropyl‐1‐(2‐methanesulfonyl‐4‐trifluoromethylphenyl)propan‐1,3‐dione, named DKN, and a benzoic acid derivative, the 2‐methanesulfonyl‐4‐trifluoromethylbenzoic acid, named BA. The adsorption/desorption processes have never been studied for isoxaflutole (IFT) at high concentrations nor for BA, and the present work aimed at completing the knowledge of the behaviour of these three molecules in conditions close to those encountered in the context of agricultural use. The adsorption/desorption study was conducted on seven soils of different physical and chemical properties, using the batch equilibrium technique. During the experiments, IFT was chemically converted into DKN in a continuous manner. This reaction appeared to be dependent on the pH of the soil and was taken into account in the calculations of the adsorbed and desorbed amounts. The adsorption isotherms obtained were predominantly C‐shaped for IFT and DKN and S‐shaped for BA, but some differences appeared on a few soils. They fitted well the Freundlich equation, and the values of the Freundlich coefficient K_fa showed that, whatever the soil, IFT was more adsorbed than its two derivatives. The main parameter influencing the adsorption of IFT appeared to be the organic matter content, whereas this effect was not evident for DKN and BA. No correlation was found between the extent of adsorption and either clay content or pH of the soil, for the three molecules.     

十种常用农药与球孢白僵菌的生物学相容性

球孢白僵菌孢子粉与10种常用农药相容性的测定结果显示,随着孢子浓度上升,所试农药对孢子的抑制作用均有不同程度的增强。在1/10田间常规使用浓度下,百菌清和代森锰锌均能抑制或杀死孢子(萌发率<1％)。除阿维菌素外,所有杀虫剂均与白僵菌孢子相容,在常规使用浓度的10倍稀释液中孢子萌发率达90％以上。吡虫啉、蚜虱灵、灭多威和氟虫腈与孢子的相容性最好,其中吡虫啉和蚜虱灵对孢子萌发率的影响不明显随药剂浓度的变化而变化,即使在田间常规使用浓度下孢子萌发率也在95％以上,而阿维菌素与白僵菌的相容性极差。因此,应用白僵菌制剂防治害虫,选择生物学相容性好的农药以低剂量与白僵菌制剂混用,既可使菌剂增效,又可大幅度降低化学药剂用量。     

厚叶软珊瑚化学成分及其细胞毒活性研究

利用多种层析方法,从厚叶软珊瑚φ=95%的乙醇提取物中获得4个化合物,通过理化性质测定和波谱分析,分别鉴定为鲨肝醇(11)、2-十六烷酸甘油酯(12)、十六烷酸乙酯(13)、5,8,11,14二十碳四烯酸酸甲酯(14),其中化合物11~14均为首次从该种中发现。对从厚叶软珊瑚获得的部分纯化合物1~10进行初步的细胞毒活性测试,结果表明,化合物4~6对人肝癌细胞株、人肺腺癌细胞株和血管内皮细胞的细胞毒性有一定的特异性,而对正常细胞的毒性较低。     

Novel Natural Compounds and Their Anatomical Distribution in the Stinging Fireworm Hermodice carunculata (Annelida)

Increasing evidence in the field of bioprospection fosters the necessity of studying poorly investigated poisonous marine invertebrates to expand knowledge on animal venom biology. Among marine annelids, amphinomid fireworms are notorious for their bearded trunk equipped with a powerful stinging capacity. Here, a methodological workflow based on analytical chemistry techniques (compound isolation followed by mass spectrometry and spectroscopy analyses) was applied to gain new insights, leading to the identification and structural elucidation of an array of natural products from Mediterranean specimens of Hermodice carunculata. Eight betaine-derived unprecedented compounds, named “carunculines”, were detected, bearing two terminal ammonium groups tri-and disubstituted at the Cα (A, B) and a series of different alkyl chains (I–VIII). The mixture of chemicals was found in all the body parts of H. carunculata, supporting a mechanism of action triggered by their vehiculation inside the dorsal chaetae, and subsequent injection when chaetae break off on contact. Preliminary investigations to understand adaptive features were also performed, showing a trend in carunculine abundance that fits into the evolutionary history of these worms. These findings shed light on the chemical ecology of amphinomids, giving reasons for the success of H. carunculata in benthic environments and providing promising novel metabolites for biotechnological implications.     

褐腐初期南方松木材微观形貌与化学成分分析

目的探究褐腐初期,腐朽菌定植对木材颜色、微观形貌以及化学成分的影响,为进一步探究木材褐腐初期降解机理提供理论基础。方法对南方松边材进行不同时长的密黏褶菌腐朽处理,利用场发射扫描电子显微镜对腐朽材的微观结构进行表征,探究褐腐菌进入木材内部的通道。同时,利用色差仪、傅里叶红外光谱、X射线能谱表征木材在不同腐朽阶段的质量损失...