不同栽培措施对双低油菜菌核病抗耐性的影响

研究不同栽培措施对双低油菜菌核病抗耐性的影响。结果表明:播期与前茬作物对双低油菜菌核病的影响达极显著水平,直播密度对双低油菜菌核病的影响达显著水平。适当晚播、水旱轮作、合理密植可有效控制或减少双低油菜菌核病的发生,增强植株的抗病性。合理增施氮肥能提高双低油菜的产量。

甜高粱病虫草害抗耐性遗传改良研究进展

回顾了世界上甜高粱病虫草害抗耐性的遗传改良研究与应用进展,为遗传改良有利于甜高粱生物燃料生产的抗耐病虫草害品种提供参考。

不同鸡腿蘑品种对霉菌抗耐能力的测定与分析

本文采用平皿培养法进行了不同鸡腿蘑品种对绿色木霉、青霉、黑根霉、黑曲霉抗耐性的研究。试验结果分析表明 :鸡腿蘑抗耐性顺序为D C - 87>Cc -173>C - 89>Cc - 1,而且这种抗耐性是在鸡腿蘑形成生长势以后才具备的。一般鸡腿蘑对黑曲霉抗性较强 ,形成了拮抗线 ,对绿色木霉和青霉的忍耐性较强。并对其机理进行了分析。

一类非对称均匀分布参数的耐抗性的估计及其优良性

文章用参数估计方法,研究了非对称均匀分布U(θ,0)的参数θ的估计及其性质,基于具有耐抗性质的分位数,得到了参数θ的估计量θn,并证明了估计量θn是参数θ的渐进无偏估计.

大球盖菇部分生物学特性研究

对大球盖菇对黑曲霉菌、青霉菌、木霉菌和粘帚霉菌的抗耐性进行研究。结果表明:大球盖菇对黑曲霉菌、木霉菌、粘帚霉菌抗性较强,形成了拮抗线,对青霉菌的忍耐性较强。并对其机理进行了分析。通过矿质元素和葛藤粉对大球盖菇菌丝产量的影响进行了试验,表明矿质元素铁、铜、钼、锌对大球盖菇菌丝体的生长有明显的促进作用,而钴、钒对菌丝的生长作用较少;不同的浓度的葛藤粉对大球盖菇菌丝体的生长有不同的促进作用,其中培养基中葛藤粉浓度为80 g/L时,对大球盖菇菌丝体的生长促进作用达到最大。

重金属胁迫与植物矿质元素交互作用的研究进展

近年来,重金属污染对农作物的影响越来越大,学者们就重金属对植物的毒害作用做了大量的研究。必需矿质元素是植物正常生长发育不可或缺的,而重金属胁迫会导致植物对必需矿质元素的吸收发生变化,进而影响植物的生理代谢。同时,矿质元素在一定条件下对重金属胁迫也具有一定的缓解作用。概述了几种主要重金属(Cd、Pb、Cu、Zn、Hg、As等)与植物矿质元素(Fe、S、P等)的交互作用,以期为提高植物重金属抗耐性提供一定的理论依据。

In vitro corrosion and antibacterial properties of layer-by-layer assembled GS/PSS coating on AZ31 magnesium alloys

To enhance the corrosion resistance of magnesium（Mg） alloy and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, Mg（OH）2 films were fabricated on AZ31 magnesium alloy substrates by an in-situ hydrothermal method and well-defined multilayer coatings, consisting of gentamicin sulfate（GS） and poly（sodium 4-styrene sulfonate）（PSS）, were prepared via layer-by-layer（Lb L） assembly. The morphologies, chemical compositions and corrosion resistance of the obtained（PSS/GS）n/Mg sample were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, electrochemical methods and immersion tests. Finally, the bactericidal activity of（PSS/GS）n/Mg samples against Staphylococcus aureus was assessed by the zone of inhibition methods and plate-counting method. The so-synthesized composite coating on the Mg alloy substrates exhibits good corrosion resistance and antibacterial performance, which make them attractive as coatings for medical implanted devices.

逆境下转BADH基因小麦甜菜碱醛脱氢酶活性表达与甜菜碱积累

对盐、旱逆境下转BADH基因小麦品系99T6的生长发育、甜菜碱醛脱氢酶活性及甜菜碱积累等进行了研究分析,结果表明,转BADH基因株系在盐逆境下具有明显的生长优势,耐盐能力达到100mmol/L;电导率和质膜相对透性表明转基因株系抗膜损伤能力增强;甜菜碱醛脱氢酶活性的增强和甜菜碱积累的增加,说明转基因株系的盐旱逆境抗性是通过甜菜碱积累这一长期、持久的方式解除渗透胁迫,而不是通过脯氨酸积累这种临时的应急反应;以甜菜碱作为靶标性状采用基因工程方法提高植物盐旱耐性是可行的。

Preparation and properties of flame-sprayed Mo-FeB-Fe cermet coatings

The powders of Mo2FeB2 cermet were prepared with Mo powders, Fe-B alloy powders and Fe powders as raw materials. Mo2FeB2 cermet coatings were prepared on Q235 steel by reactive thermal spraying （RTS） method and heated at 1 000 ℃ in vacuum oven of 1 kPa for 5 h. The properties of coatings were investigated. The results indicate that Fe2B appears after milling for 15 h in the powder at room temperature, a part of ternary borides （Mo2FeB2） are generated in powder sintered at 900 ℃. The coatings are composed of the major phases Mo2FeB2 and a-Fe, a little of Fe203, FeO and some pores. The bonding strength between the substrate and the ceramic coating is 32.73 MPa, the thermal-shock times is about 43 and the wear resistance is enhanced by approximately 5.28 times compared with that of the substrate, respectively. The comprehensive properties of Mo2FeB2 cermet coatings can be imoroved further after vacuum heat-treatment at 1 000 ℃ for 5 h.

Chemical composition and anti-MRSA activity of the essential oil from Chinese eaglewood

To analyze the constituents of essential oil from Chinese eaglewood [resinous wood of Aquilaria sinensis （Lour.） Gilg] and its anti-methicillin-resistant Staphylococcus aureus （MRSA） activity. The essential oil was extracted by water-steam distillation and analyzed by GC/MS method. The relative contents of the compounds were determined by normalization. The compounds were characterized by NIST05 and WILEY275L database matching and comparison of their MS spectra with those of literature data. Antibacterial activity of the oil was assayed by the filter paper disc agar diffusion method. The oil showed significant antibacterial activity against MRSA. Sixty-six chromatographic peaks were detected, among them thirty compounds comprising 59.80% of the total essential oil were characterized. Twenty-six compounds comprising 54.26% of the oil were identified as sesquiterpenes. β-Agarofuran （8.96%）, kusunol （7.82%）, （-）-jinkoh-eremol （5.04%）, agarospirol （4.53%）, baimuxifuranic acid （4.09%） were the major sesquiterpenes. Four nor-sesquiterpenes and some other sesquiterpenes, such as 10-epi-γ-eudesmol, α-agarofuran, epi-ligulyl oxide, etc. were detected in Chinese eaglewood oil for the first time. This is the first report about anti-MRSA activity of Chinese eaglewood oil from A. sinensis.

Comparative Analysis on Cadmium Tolerance and Antioxidant Enzymatic Activities of Two Viola Species

[Objective]This study aimed at exploring the physiological properties of the known Cd hyperaccumulator Viola baoshanensis and the control plant Viola inconspicua to cadmium stress.[Method]After a hydroponic experiment carried in a greenhouse,plant Cd accumulations,root elongation rates,MDA contents,and antioxidant enzyme activities were determinined.[Result]Both Viola baoshanensis and Viola inconspicua showed high levels of Cd uptake growing in Cd-supplemented solution of 300 μmol/L for 12 d with Cd accumulations of 2 595 and 3 330 mg/kg in the shoots,respectively.In the cultural solution supplemented with 300 μmol/L of Cd,the root elongation rates were not affected and the MDA contents decreased significantly in Viola baoshanensis,while the root elongation rates were significantly inhibited and the MDA contents increased remarkably in Viola inconspicua,which indicated that Viola baoshanensis had the higher Cd tolerance.The superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）activities of two Viola species were not linearly related to the middle and low Cd-supplemented concentrations（5,50 μmol/L）and had attained the tiptop in cultural solution supplemented with 100 or 300 μmol/L of Cd but declined in cultural solution supplemented with 500 μmol/L of Cd,suggesting that the contribution of antioxidative enzymes was limited to the Cd tolerance of Viola plants.The Viola inconspicua showed a strong adaptability to the middle and low concentrations of Cd.[Conclusion]Viola species could be used as potential plant resources for the phytoremediation of agriculture areas polluted with low and even middle levels of Cd.

蛋白酶分泌菌对重金属胁迫的反应

本文研究了Pb、Zn、Cu和Cd对3种蛋白酶产生菌:碱性地衣芽孢杆菌2709(Bacillus licheniformis 2709)、中性枯草杆菌1.398(Bacillus subtilis1.398)和酸性宇佐美曲霉537(Aspergillus usamii 537)生长及其酶活性的影响,并采用生长抑制皿分析(GIPA)方法针对3种菌株在Pb、Zn、Cu、Cd不同胁迫浓度下的生长量进行打分,分析其耐性与抗性指标(MTC与MIC)。结果表明4种重金属在超过一定临界浓度后,对3种菌株的生长和蛋白酶活性均产生了较大的抑制作用。碱性蛋白酶对4种重金属均具有较大的适应性,其次是中性蛋白酶对Zn和Cd具有一定的适应性,而酸性蛋白酶对4种重金属均表现出被抑制状态。3种菌株对Pb和Zn耐性与抗性最高(2.0mmol/L～6.0mmol/L),其次是对Cd也具有一定的抗性(0.5mmol/L～0.75mmol/L)。

Preparation of MgO whisker from magnesite tailings and its application

Magnesium carbonate whisker as precursor was prepared from the low-grade magnesite tailings by the route of calcination, hydration, carbonation and thermal decomposition, and then MgO whisker was prepared by calcining the precursor. In addition, the effect of MgO whisker addition on sintering and thermal shock resistance of refractory was also investigated. The results show that the thermal decomposition product is MgCO3·3H2O and its morphology is remarkably influenced by the types of additives, and magnesium carbonate whisker with the length of 10-60 μm and length-diameter ratio of 10-20 is successfully prepared when a type of soluble magnesium salt is added. MgO whisker with the length of 10-40 μm is derived from precursor with the heating rate of 1 ℃/min. The thermal shock resistance of refractory is significantly improved by the addition of MgO whisker due to its effect on binding and preventing crack expanding, and the proper amount of whisker addition is around 3%.

Research Progress and Identification Method of Apple Stress Resistance

In the research, changes of apple chemistry, and molecule, under stresses, are n terms of morphology, physiology, bio- illustrated and research and identifica- tion methods of apple resistance are explored involving drought-resistance, flood-re- sistance, salt-stress resistance, cold-hardiness and heat-resistance. In addition prospects of apple resistance research are proposed, as well.

Effects of surface roughness of substrate on properties of Ti/TiN/Zr/ZrN multilayer coatings

Ti/TiN/Zr/ZrN multilayer coatings were deposited on Cr_17Ni_2 steel substrates with different surface roughnesses by vacuum cathodic arc deposition method. Microstructure, micro-hardness, adhesion strength and cross-sectional morphology of the obtained multilayer coatings were investigated. The results show that the Vickers hardness of Ti/TiN/Zr/ZrN multilayer coating, with a film thickness of 11.37 μm, is 29.36 GPa. The erosion and salt spray resistance performance of Cr_17Ni_2 steel substrates can be evidently improved by Ti/TiN/Zr/ZrN multilayer coating. The surface roughness of Cr_17Ni_2 steel substrates plays an important role in determining the mechanical and erosion performances of Ti/TiN/Zr/ZrN multilayer coatings. Overall, a low value of the surface roughness of substrates corresponds to an improved performance of erosion and salt spray resistance of multilayer coatings. The optimized performance of Ti/TiN/Zr/ZrN multilayer coatings can be achieved provided that the surface roughness of Cr_17Ni_2 steel substrates is lower than 0.4μm.

Susceptibility of 30 Antimicrobial Agents in 200 Strains of Campylobacters

为了解近几年弯曲菌对抗生素的敏感性，我们采用琼脂扩散法进行了200株弯曲菌对30种抗生素的敏感实验，结果 1994－1998氨基糖苷类、硫霉素、多粘菌素B、克拉霉素、交沙霉素、麦迪霉素均无耐药菌。红霉素耐药率为3％；氟喹诺酮类为44．5％。另外，氟喹诺酮类有完全性交叉耐药。红霉素和庆大霉素耐药菌五年来相对稳定，仍可用来治疗弯曲菌肠炎。我们这一地区氟喹诺酮类严重耐药，将来应严格控制使用。

Effect of Polyamine Priming on Chilling Tolerance of Lolium perenne during Seed Imbibition

[Objective] This study aimed to investigate the effect of potyamine priming on physiological and biochemical variations of Lolium perenne embryos and seed germination. [Method] With annual Lolium perenne （Diamond T and Grazing-8000） as experimental materials, after priming with 0.5 mmol/L putrescine （Put）, spermidine （Spd） and spermine （Spm） for 24 h and chilling imbibition at 5 ℃ for 12, 24, 36 and 48 h, the effect of Put, Spd and Spm priming on chilling tolerance and germination ability of annual Lolium perenne seeds during imbibition was investigated. [Result] Put, Spd and Spm priming improved the activities of peroxidase （POD）, catalase （CAT）, superoxide dismutase （SOD） and ascorbate peroxidase （APX） and content of soluble protein content under low temperature stress, significantly in-creased the germination rate, and shortened the average germination duration. After chilling imbibition for 48 h, compared with the control, the average germination rate of annual Lolium perenne seeds was improved by 15.5% and 12.0% after Put, Spd and Spm priming, and the average germination duration was shortened by 1.21 and 1.14 d. During seed imbibition, the chilling tolerance of Grazing-8000 was stronger than that of Diamond T. Overall, Put, Spd and Spm treatment could increase the chilling tolerance of annual Lolium perenne seeds during imbibition, and improve the germination ability of seeds under low temperature stress. [Conclusion] Results of this study provided theoretical basis for the application of seed priming technology in the production of annual ryegrass.

Effects of Hg and Ga on microstructures and electrochemical corrosion behaviors of Mg anode alloys

The effects of Hg and Ga on the electrochemical corrosion behaviors of the Mg-2%Hg, Mg-2%Ga and Mg-2%Hg-2%Ga (mass fraction) alloys were investigated by measurements of polarization curves, galvanostatic tests and measurements of electrochemical impedance spectroscopy. Scanning electron microscopy, X-ray diffractometry and energy dispersive spectrometry were employed to characterize the microstructures and the corroded surface of the above alloys. The results demonstrate that the microstructure of the Mg-2%Ga alloy is solid solution and the Mg-2%Hg and Mg-2%Hg-2%Ga alloys have white second-phases at the grain boundaries. The Mg-2%Ga alloy has the worst electrochemical activity and the best corrosion resistance, showing a mean potential of -1.48 V and a corrosion current density of 0.15 mA/cm2. The Mg-2%Hg-2%Ga alloy has the best electrochemical activity and the worst corrosion resistance, showing a mean potential of -1.848 V and a corrosion current density of 2.136 mA/cm2. The activation mechanism of the Mg-Hg-Ga alloy is dissolution-deposition of the Hg and Ga atoms.

Photosynthesis of Resurrection Angiosperms

Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content and chloroplast structure little changed in the course of desiccation, therefore has been called homoiochlorophyllous desiccation-tolerant plants (HDTs). Another type of resurrection angiosperms that lost its chlorophyll dining desiccation is called poikilochlorophyllous desiccation-tolerant plants (PDTs). HDTs have been received more attention because of simplicity of protection mechanism which is much easy to the study and utilization of the desiccation tolerance of resurrection angiosperms. Recent advances in studies of photosynthesis of resurrection angiosperms indicate that photochemical activities are sensitive indicators for the study of physiological state of resurrection angiosperms during desiccation and rehydration. Photochemical activities of resurrection angiosperms are inhibited with loss of water similar to those of general plants, however, the magic thing is that they could reactivate rapidly during rehydration even losing more than 95% water. Up-regulations in xanthophyll cycle and antioxidative systems as well as preservation in integrity and stability of photosynthetic membranes during desiccation may be very important to desiccation tolerance of resurrection angiosperms. The fact that phosphate treatment in rehydration stage also strongly influences resurrection indicated importance of studies on rehydration stages of resurrection angiosperms.

Is the Potential Interconnection between Antibiotic Susceptibility and Disinfectant Resistance a Threat to Food Safety?

The prevalence of antibiotic susceptibility and disinfectant resistance in bacterial pathogens causes a serious problem not only to food safety but also to public health, which directly or indirectly leads to treatment and disinfection failures. In this review, multidrug resistance, the mechanism of disinfectant resistance, the methods for detecting disinfectant resistance and the cross-resistance between an- tibiotics and disinfectants are summarized. More efforts should be devoted to explor- ing the professional guidance of using antibiotics and disinfectants, and to develop- ing the comprehensive detection with genetic and molecular methods is highly ex- pected.