Growth promotion and protection against salt stress by Pseudomonas putida Rs-198 on cotton

The strain Rs-198 isolated from alkaline soil was investigated and identified as Pseudomonas putida on the basis of its physiological and biochemical properties as well as its 16S rDNA sequence analysis. The effects of the strain Rs-198 on cotton seedling growth under salt stress were studied. The results indicated that Rs-198 could protect against salt stress and promote cotton seedling growth. After treatment with Rs-198, the germination rate and healthy stand of cotton were increased by 23.8% and 30.7%, respectively. Individual plant height, fresh weight and dry weight of cotton seedling were increased by 12.8%, 30.7% and 10.0%, respectively as compared to the control (CK). In the fields, Rs-198 also exhibited the ability to increase the cotton's germination rate and healthy stand, which were 16.0% and 22.4% higher than that of CK. Further analysis showed that Rs-198 could increase the absorption of the Mg²⁺, K⁺ and Ca²⁺ and decrease the uptake of the Na⁺ from the soil and also improve the production of endogenous indole acetic acid (IAA) content and reduce the abscisic acid (ABA) content of cotton seedling under salt stress.     

Studies on the Oxidation of Weathered Coal with Nitric Acid

A raseach has been done on the possibility of producing nitriochumic acid fromweathered coal of Nantong,Sichuan,oxidised by nithic acid.The optimun reacting conditions,whichare found through the way of orthogonal experiment,are suggested as follows:concentration ofHON3 35%,rate of HON3 to coal 3.5,reacting take 15 min,and reaction temperature 369 K. Thecomposition of product is Wf 2. 91 %;Ag 14.06%;HAg 78.28%;Ng 1.62%.     

脱硫石膏改良重度苏打盐化土的环境效应

为了解连续施用脱硫石膏改良苏打盐化土的持续效应及环境效应,以经过3a大田连续施用不同量脱硫石膏(0,15,22.5,30t/hm~2)改良的重度苏打盐化土为供试土壤,采用盆栽试验方法,研究2a盆栽试验后,脱硫石膏的持续效应对饲草玉米生长、土壤环境以及农作物中重金属累积的影响。结果表明:15t/hm~2用量的脱硫石膏可以显著提高饲草玉米的出苗率、株高、茎粗和生物量,较对照分别提高20.6%,16.8%,8.1%和10.1%,试验范围内改良效果最佳。脱硫石膏使土壤的pH、EC降低,Na~+减少,Ca~(2+)和SO_4~(2-)增加,且脱硫石膏用量越大,影响越大。土壤和饲草玉米地下部中的As、Hg、Ni含量随脱硫石膏用量的增加而增加,试验范围内土壤重金属含量均符合二级国家土壤环境安全标准(GB 15618—1995)。饲草玉米地上部重金属含量与脱硫石膏添加量无显著相关关系,根据饲料卫生标准(GB 13078—2001),各处理玉米中重金属含量均未超标。饲草玉米对重金属的富集作用地下部大于地上部,且对不同重金属富集能力CdHgAsNi。利用适量的脱硫石膏量改良苏打盐化土的持续效应良好,且对环境未造成不良影响。     

Incorporation of urea-derived 13C into microbial communities in four different agriculture soils

The objective of this study was to investigate changes in the composition of the soil microbial community brought about by urea application and differences in the incorporation of urea-derived C into the soil phospholipid fatty acid (PLFA) pool at differing soil pH. We selected four soils which ranged in pH from 3.9 to 7.8. ¹³C-labeled urea was applied at two concentrations 100 and 200 mg N kg^?1 which represents commonly used and high levels of application. Significant hydrolysis of applied urea occurred within 2 h; less than 2 % of urea-C was retained in the soil with one exception, the fluvo-aquic soil at pH 7.8 amended with 200 mg kg^?1 urea-N 3 days after urea application. According to principal component analysis (PCA), the effect of urea and incubation time on microbial community composition was far weaker than differences between the four soils due to their large differences in basic properties; the scores of PC2 were significantly correlated with pH values. The incorporation of ¹³C-urea to PLFAs increased with soil pH; this may be related to increases in the speciation of inorganic C into bicarbonate.¹³C label was primarily incorporated into 16:1ω5c, 16:0, and cy19:0 in red soil, pH 3.9; and into 16:1ω7c, 16:0, and 16:1ω5c in fluvo-aquic soil, pH 7.8. A wider range of PLFAs became labeled in the two paddy soils at pH 5.2 and 6.7. This suggests that the profile of PLFAs labeled from the application of ¹³C-urea may be affected by redox potential.     

热加工过程中鲍鱼腹足蛋白间作用力及其质构特性

为探究蛋白质形成凝胶过程中其化学作用力的变化规律以及与凝胶特性之间的关系,该文以鲍鱼腹足为原料,采用溶液分级提取方法,并结合扫描电镜和红外光谱法,考察热加工中鲍鱼腹足蛋白间作用力及其质构特性的变化情况。结果表明,随着加热温度升高(60、80、100℃),扫描电镜结果显示,鲍鱼腹足中间部位与边缘和过渡部位形成孔洞较小、排列紧密的网络结构,同时红外结果表明,随温度升高,蛋白二级结构发生明显变化,N-H弯曲和C-N伸缩振动较为明显,α-螺旋变为无规则卷曲结构,肌球蛋白疏水性增加,-S-S-形成。此时,对应离子键、氢键含量均呈下降趋势,疏水键相对含量呈先上升后下降趋势,二硫键、非二硫共价键含量呈上升趋势。进一步研究表明,各化学作用力与蛋白凝胶质构特性具有高度相关性。在较低温度下(60℃)离子键、氢键和疏水键对凝胶稳定性起主要作用,此时形成的凝胶较柔软;在较高温度下(80、100℃)二硫键、非二硫共价键为维持凝胶稳定的主要作用力,此时凝胶特性较佳,富有弹性、较好的凝聚性和回复性。该研究为热加工过程中鲍鱼腹足蛋白质变化的机理提供参考依据。     

Molecular community analysis of arbuscular mycorrhizal fungi associated with five selected plant species from heavy metal polluted soils

Arbuscular mycorrhizal fungi (AMF) are known to play an important role in plant tolerance to heavy metals (HMs) stress. This study aimed to understand the diversity of AMF communities associated with five selected plant species (Phytolacca americana, Rehmannia glutinosa, Perilla frutescens, Litsea cubeba and Dysphania ambrosioides) from severely HMs polluted soils in Dabaoshan Mine region, China, using molecular methods. Plant roots and rhizospheric soils were sampled from four sites, respectively. Targeting the fungal small subunit (SSU) rRNA gene, PCR-denaturing gradient gel electrophoresis (DGGE) analysis indicated that varied AMF communities colonized different plant species, and the AMF communities in rhizospheric soils were different from those in plant roots. Total six SSU rRNA gene clone libraries including four root samples and two rhizospheric soil samples were constructed. Screening clone libraries by DGGE and sequence analysis revealed that Glomus dominated all of the samples except for the roots of D. ambrosioides, while Kuklospora and Ambispora dominated the roots of D. ambrosioides and the rhizosphere of P. americana. This study indicates that diverse AMF are associated with these selected plants, and they are potentially useful to promote the phytoremediation of this HMs polluted area.     

Soil pH controls nitrification and carbon substrate utilization more than urea or charcoal in some highly acidic soils

Understanding the mechanism and key controlling factors of nitrification in highly acidic soils is important from both ecological and environmental perspectives. Many acid soils are also characterized by vegetation that produces polyphenolic and terpene compounds that inhibit microbial activity. We investigated the potentially ameliorative effects of lime, charcoal, and urea additions on soil nitrification and carbon substrate utilization (using the MicroResp method). Four soils were studied from widely different environments but with similar pH and inputs of phytochemicals to determine the relative effects of these potentially controlling factors. The addition of charcoal had no significant effect on net nitrification, but charcoal significantly increased soil basal respiration and altered C substrate utilization in the two Scottish soils. Urea greatly increased nitrification in both the Chinese soils, but there was no effect of urea on nitrification in the two Scottish soils. Lime application increased nitrification in all the soils except for the Chinese mixed forest soil. Multivariate analysis of the C source utilization data revealed that lime altered C substrate utilization more than urea or charcoal in these highly acidic soils. Our results suggest that acid-tolerant nitrifiers do exist in these soils and have potential for high activity, and pH (lime addition) and N-substrate (urea) most often increased nitrification. However, no single factor controlled nitrification in every soil, suggesting an interaction between abiotic and nitrifier community composition as a result of land use and soil type interactions.     

榕管蓟马防治高效菌株蜡蚧轮枝菌V3450固态发酵基质配方筛选

蜡蚧轮枝菌V3450是榕管蓟马防治的高效菌株,为实现该菌株的放大培养,以盆栽榕树出口使用的主要栽培基质椰糠和单一固态发酵培养产孢量最多的麦麸为主载体,开展该菌株的固态发酵基质一般组合配方和正交组合配方筛选试验。结果表明：一般组合固态发酵基质配方5（椰糠+麦麸+磷酸盐+酵母粉=7.5 g+7.5 g+0.2 g+0.5 g）为最好的初筛配方,蜡蚧轮枝菌V3450菌株固态发酵培养所需基质的4个基本组分因子为麦麸、椰糠、磷酸盐和酵母粉;正交组合固态发酵基质配方8（麦麸:椰糠:磷酸盐:酵母粉=3:2:3:2）为最佳的组合配方,麦麸、椰糠、磷酸盐和酵母粉等4个基本组分因子的最佳质量配比为3:2:3:2。正交组合配方8（麦麸:椰糠:磷酸盐:酵母粉=3:2:3:2）是蜡蚧轮枝菌V3450菌株的最佳固态发酵基质配方,放大培养的真菌孢子对榕管蓟马成虫具有很强的侵染力。     

高温胁迫对北美海棠‘金吉丽’和‘特丽’的生理指标影响

北美海棠较湖北海棠具有更高的观赏价值,武汉夏季高温是限制北美海棠推广应用的关键因素。以北美海棠‘金吉丽’和‘特丽’为试材,以本地乡土植物湖北海棠为对照,经过1周35℃高温处理,测定海棠叶片的抗性生理指标变化。结果表明：北美海棠的叶绿素含量和保护酶活性高于湖北海棠、可溶性蛋白质含量低于湖北海棠、丙二醛含量与湖北海棠相似,总体来看,北美海棠抗性生理指标变化与本地乡土植物湖北海棠抗性生理相似。结合前期的形态学研究,进一步从生理水平上佐证了这2个北美海棠品种在武汉地区能够自然生长。     

丘陵地区鹰嘴蜜桃果树修枝装置的设计

针对丘陵地区鹰嘴蜜桃果树修枝费时费工的问题,结合种植区域地形特点和果树枝干分布特性,设计一套易于果农操作的修枝装置,该修枝装置包括修枝执行机构、电动伸缩机构、支撑小车、电气控制4部分。采用圆锯刀修枝方式,根据树杆对锯片的作用力选择修枝电机的功率;采用滚珠丝杆实现修枝执行机构的伸缩功能,避免果农攀爬;支撑小车的设计解决了果农手持修枝工具费力的问题。该装置适用于平地、山地等多种地形,安全可靠,省时省力,大大提高了修枝效率。