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51.
Mohamed EL‐SHEHABY Mohamed Sayed SALAMA Elisabeth BRUNNER Jürgen HEINZE 《Integrative zoology》2011,6(3):259-265
Discrimination between nestmates and non‐nestmates in social insects is thought to rely on the pattern of cuticular hydrocarbons. We investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species, Temnothorax nylanderi (Förster, 1850) and Temnothorax crassispinus (Karavaiev, 1926), and their hybrid. We found that although the profiles show considerable similarities, a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 taxa. The profiles of hybrids were not consistently intermediate between those of the paternal species, suggesting either non‐additive interactions among the parental biosynthetic pathways or systematic differences in environment‐derived odor cues. 相似文献
52.
不同无机硫对内蒙古白绒山羊消化代谢的影响 总被引:3,自引:1,他引:3
选用9只装有瘤胃和十二指肠近端瘘管的内蒙古白绒山羊羯羊(2周岁左右),随机分成3组,分别饲喂氮硫比相同而硫源不同(分别为硫磺,硫化钠和硫酸钠)的3种日粮,进行消化代谢试验和测定食糜流通量,以探讨不同无机硫对氮和硫的沉积量以及硫的流通规律,试验结果表明:硫酸钠组氮的进食量和沉积量均显著高于硫磺组和硫化钠组(P<0.05),但各组间氮的表观消化率差异不显著(P>0.05),硫化钠组和硫酸钠组硫的沉积量以及表观消化率均显著高于硫磺组(P<0.05),硫酸盐在瘤胃吸收量很少,主要在肠道被吸收;硫化物在瘤胃和小肠均可被吸收利用,元素硫(硫磺)主要在瘤胃和小肠前段被分解利用,元素硫的生物学效价显著低于硫酸钠和硫化钠(P<0.05)。总之,添加硫酸钠对内蒙古白绒山羊的效果好于硫磺和硫化钠。 相似文献
53.
Oxidation of elemental sulfur (S0) in 20 Chinese agricultural soils was tested and the effects of previous S0 applications on the oxidation of additional applied S0 in selected soils were investigated using laboratory, greenhouse, and field experiments. Results showed that sulfur oxidative capacities presented great variability among 20 tested soils, with a coefficient of variation of 92.4%. There were no significant relationships between S0 oxidation and physical and chemical properties of the selected soil. Previous S0 amendment significantly increased the oxidation rate of additional applied S0. These stimulatory effects after the first applications of S0 were greater than those after two applications. The percent increase in S0 oxidation rate due to S0 pretreatment was negatively correlated with the oxidation capacities of soils before S0 pretreatments. The significant reduction of sulfur oxidation in autoclaved soils and significant increase in S0 oxidation after inoculation with S0-treated soil suspension demonstrated that microbial oxidation was mainly responsible for the enhancement of soil oxidation ability after previous S0 amendments. 相似文献
54.
The arylsulfatase activity of soil and humic arylsulfatase complexes extracted from soil were measured using the substrates p-nitrophenyl sulfate and low molecular weight (500–10000) soil ester sulfate compounds. Soil samples from the Aphorizon of a Podzol from S-amended wheat plots and a Regosol from dykeland hayfield plots were investigated. Soil arylsulfatase activity (assayed with p-nitrophenyl sulfate) in the fall was significantly higher than spring samples; however, no seasonal differences were observed when humic-arylsulfatase complexes were assayed with p-nitrophenyl sulfate. The discrepancy between arylsulfatase activity in soil and soil extracts was probably due to inhibitors which were found in soil materials. These results appear to support the theory that abiotic arylsulfatase is a relatively stable and persistent component of soil. There was a marked difference in the response by humic-arylsulfatase complexes to the artificial substrate p-nitrophenyl sulfate and natural low molecular weight soil substrates. Humic-arylsulfatase complexes hydrolysed 35–80% of added low molecular weight substrates depending on the treatment. The molecular size, concentration, and chemical composition of the low molecular weight ester sulfate compounds affected hydrolysis of the low molecular weight substrates. The response by humic-arylsulfatase complexes to the chromogenic ester sulfate, p-nitrophenyl sulfate did not reflect the ability of these complexes to hydrolyse natural soil substrates. In an experiments we examined arylsulfatase activity and soil S status in relation to the total S in plant tissue and grain from wheat plants grown in the Podzol. Tissue S was more strongly associated with soil S than the wheat grain. Hydriodic acid-S, Ca(H2PO4)2-extractable sulfate, and hydrolysable ester sulfates in the high molecular weight (>10000) and low molecular weight (500–10000) fractions of soil organic matter extracts were strongly positively correlated with tissue S. Arylsulfatase activity in soil and humic-arylsulfatase extracts assayed with p-nitrophenyl sulfate were also strongly correlated with tissue S, while humic-arylsulfatase activity assayed with the low molecular weight substrate was negatively correlated with tissue S. 相似文献
55.
Global forest systems: An uncertain response to atmospheric pollutants and global climate change? 总被引:1,自引:0,他引:1
Forest systems cover more than 4.1×109 ha of the Earth's land area. The future response and feedbacks of forest systems to atmospheric pollutants and projected climate change may be significant. Boreal, temperate and tropical forest systems play a prominent role in carbon (C), nitrogen (N) and sulfur (S) biogeochemical cycles at regional and global scales. The timing and magnitude of future changes in forest systems will depend on environmental factors such as a changing global climate, an accumulation of CO2 in the atmosphere, and increase global mineralization of nutrients such as N and S. The interactive effects of all these factors on the world's forest regions are complex and not intuitively obvious and are likely to differ among geographic regions. Although the potential effects of some atmospheric pollutants on forest systems have been observed or simulated, large uncertainty exists in our ability to project future forest distribution, composition and productivity under transient or nontransient global climate change scenarios. The potential to manage and adapt forests to future global environmental conditions varies widely among nations. Mitigation practices, such as liming or fertilization to ameliorate excess NOx or SOx or forest management to sequester CO2 are now being applied in selected nations worldwide.The U.S. Government's right to a non-exclusive, royalty free licence in and to any copyright is acknowledged. 相似文献
56.
Aggregate associated carbon, nitrogen and sulfur and their ratios in long-term fertilized soils 总被引:3,自引:0,他引:3
Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka−1 and high level of 60 Mg ka−1) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1–2 mm) and microaggregates (<0.106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5–1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5–1 and <0.106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher C/N, C/S and N/S ratios were found both in large dry aggregates (>20 and 6–20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0.106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered. 相似文献
57.
P. J. Randall 《Journal of plant nutrition》2015,38(2):212-223
Winged bean [Psophocarpus tetragonolobus (L.) DC] plants, line UPS31, were grown in pots of sulfur (S)-deficient soil in a glasshouse without added S or with five levels of added S. The seed was inoculated with rhizobia (Bradyrhizobia sp. strain CB756) and plants were later given additional mineral nitrogen (N). Harvests of shoots were made at 39 and 78 days after sowing (DAS). Shoot dry matter yield, total S (ST), S reducible by hydriodic acid (SHI) – a measure of sulfate – and N were determined. At 78 DAS, the critical concentration (at 90% maximum yield) of ST in shoots was 0.9 mg S g?1 dry matter and in young leaves was 1.4 mg S g?1 dry matter. Plants with these concentrations or below would be considered S-deficient. The usefulness of critical concentrations of SHI or ratios of SHI/ST, and N/ST as indicators of S status is discussed. 相似文献
58.
Phillip F. Steyn BVSc MRCVS MS David Twedt DVM Wanda Toombs CVT 《Veterinary radiology & ultrasound》1995,36(4):327-331
The gastric emptying half-time of solid food in normal cats was determined using a scintigraphic technique. 99m Tc-sulfur colloid was applied to dry food. Sequential images were acquired post prandial, and the gastric emptying half-time was determined for several different acquisition and processing parameters. Good correlation was found between different acquisition and processing methods, some of which made use of edge detection applications, while others used different views, or number of views from which the gastric emptying half-time was calculated. The mean ± standard deviation, (range) and median of the gastric emptying half-time determined using the geometric mean of total counts in hand-drawn regions of interest from the lateral and ventral images were 2.47 × 0.71, (1.42–3.61) and 2.37 hours respectably. 相似文献
59.
宝交早生草莓在0℃下自然降氧贮藏10 d,好果率84%,商品率达98%。用10%CO_2处理可将草莓在0℃的贮藏时间延长到20 d,好果率和商品率均为94%,CO_2浓度超过20%会使草莓产生酒精味。SO_2慢性释放剂处理也有较好的防腐效果。 相似文献
60.