氮素运筹对淮北地区超高产小麦养分吸收利用的影响

2006～2008年,以强筋小麦烟农19和中筋小麦皖麦50为材料,研究了氮素不同基追肥比例对小麦植株养分含量、肥料吸收及其利用效率的影响。结果表明,小麦产量达9000 kg/hm2以上的超高产水平,每公顷吸收氮、磷、钾量分别为259.25～315.00 kg、82.86～89.70 kg、224.67～305.28 kg; 形成100 kg子粒消耗的氮、磷、钾量分别为2.933.19 kg、0.871.04 kg、2.473.27 kg。两品种氮肥当季利用率随拔节肥比例增加显著提高,当基追比例为6∶44∶6时,烟农19的氮肥当季利用率高于皖麦50,说明适宜的氮肥运筹比例有利于提高氮肥当季利用率; 氮肥农学效率、氮收获指数与产量间呈显著正相关。随拔节肥比例增加,氮素利用效率有下降的趋势,说明植株随吸氮量的增加,子粒形成产量增幅减弱。淮北地区小麦实现超高产栽培的拔节期追肥的适宜的氮素基追比例为5∶5～4∶6。     

Chemical effect of NO on oxidation of CH4

A new chemical kinetic mechanism model of NO-CH4 interaction is adopted to simulate the reaction process of CH4 in the plug flow reactor (PRF) and HCCI engine based on the experimental verification. The initial NO mole concentration and reaction temperature are changed and the effect of NO on CH4 oxidation is analyzed. The results show that: NO mainly reacts with alkylperoxy ROO·produced in CH4 oxidative reaction, and alkylperoxy ROO · is transformed into alkoxy radicals RO ·. NO accelerates the oxidation of CH4 at low concentration. With the concentration of NO rising, its performance of speeding up fuel oxidation is inhibited. At low temperature, NO promotes oxidation of CH4. But at high temperature, due to low concentration of alkylperoxy ROO ·, NO almost loses its effects. The effect of NO on ignition delay of HCCI combustion is closely related to its concentration. The ignition delay reduces when NO is at low concentration, and the trend reducing the ignition delay slows down at high concentration. These results are mainly based on competition between R126 and R150.     

Spatial and temporal distribution of temperature of drivage roadway air after methane explosions

The spatial and temporal distribution of air temperature after methane explosions in drivage roadway is studied based on the relationship between overpressure and temperature which is found based on gas equation, dynamic and functional principles. The moment temperature distribution after methane explosions under different concentrations of methane is got through solution to the overpressure model and connection with experimental data. Based on unsteady mass and heat transfer, and other physical phenomena, the controlling equations of mass, momentum and energy are founded. The instantaneous temperature distribution after methane explosions is used as one kind of initial conditions of RNG k-ε model to solve the spatial and temporal distribution of temperature in drivage roadway. Studying on it has great meaning to understand the mechanism of sub-fire or sub-explosions induced by initial explosions. It could provide some understanding and helpful methods to prevent and control those sub-disasters.     

小牛血清对耐辐射奇球菌类胡萝卜素在肿瘤细胞中吸收的影响

耐辐射奇球菌类胡萝卜素deinoxanthin的抗氧化活性高于β-类胡萝卜素等,并且是参与耐辐射奇球菌极端抗性的重要物质。但是,deinoxanthin溶液在体外对光、氧等因素不稳定。本文旨在研究deinoxanthin的有效溶剂载体系统,并以此载体研究deinoxanthin对人卵巢癌细胞系A2780的药理学作用。通...     

Co-localization of atmospheric H2 oxidation activity and high affinity H2-oxidizing bacteria in non-axenic soil and sterile soil amended with Streptomyces sp. PCB7

Two complementary experimental approaches were utilized to examine the extent to which free soil hydrogenases and H₂-oxidizing bacteria contribute to the soil uptake of atmospheric H₂. First, high affinity hydrogenase activity and H₂-oxidizing bacteria were fractionated in non-axenic soil and axenic soil colonized with the high affinity H₂-oxidizing bacterium Streptomyces sp. PCB7. Non-axenic soil was fractionated by buoyant density centrifugation. High affinity H₂ oxidation activity measured in individual fractions was proportional to the copy number of hhyL gene, specifying the large subunit of putative high affinity [NiFe]-hydrogenases. 2.5% of the hydrogenase activity was recovered in bacteria-free soil extract. Similarly, sequential centrifugation and wet filtrations of strain PCB7-colonized soil dispersed in solubilization buffer caused a loss of the activity, at a ratio proportional to the number of living cells removed. No abiontic hydrogenase activity was detected in bacteria-free fractions. The second experimental approach was designed to verify whether or not the [NiFe]-hydrogenase of strain PCB7 retains high affinity H₂ oxidation activity in soil, under the abiontic state. H₂ oxidation rates of crude enzyme extract of strain PCB7 measured under aerobic and anaerobic conditions were indistinguishable, indicating that the high affinity hydrogenase of strain PCB7 is oxygen-tolerant. The hydrogenase activity of sterile soil spiked with as much as 0.14 mg_(protein) g_(soil-dw)⁻¹ was equivalent to the H₂-oxidation activity of only 10⁶-10⁷ CFU of strain PCB7 g_(soil-dw)⁻¹. Taken together, our results indicate that high affinity hydrogenase activity is proportional to the abundance of H₂-oxidizing bacteria in soil and, that abiontic hydrogenases contribute only a few percent of the total high affinity H₂ oxidation activity detected in soil.     

Test and numerical simulation on effect of enhanced coalbed methane drawing by injecting gas under coal mine

In order to improve the extraction effect of ultra-low permeability coalbed methane, injecting and drawing industry test of enhanced coalbed methane recovery is carried out by injecting concentration 78% N2 under 850 m depth coal mine of Tianfu Mining Co. Ltd.,in Chongqing. The experiments of free methane emission, vacuum pumping, side injecting and side emission, side injecting and side drawing and intermittent injecting are tested under the condition of single hole and multi holes respectively. The testing results indicate that time-concentration curve of methane drawing is a single peak wave curve which increases and decreases during injecting N2 after reaching the limits of ordinary extraction. The methane concentration of intermittent injecting gas is greater than that of side injecting and side drawing. However, the former declines rapidly and has a shorter migration distance than the latter. The injecting effect of long time side injecting and side drawing is better than that of intermittent injecting. When hole space is 4 m, permeability 1.112×10-4mD, the methane recovery ratio increases to 58.6％ from conventional recovery ratio 52.4% after injecting 5 day. Meanwhile, the seepage flow equation of injecting air is provided and the parameters, such as rational hole mesh space, time and pressure of injecting gas, are simulated. At the same time, application condition and assistant technology about injecting gas are discussed, which provides engineering and theoretical reference to promote the injecting gas technology. Also, the problem of variable definite conditions seepage flow equation is put forward.     

Science and elephant management decisions in South Africa

Most conservation practitioners rely on experience-based information for management decisions. In South Africa, government policy thus directs managers to base decisions for elephant management on the best available scientific information. The reliance of their management decisions on science, however, is unknown. We interviewed 30 managers from small to large protected areas in South Africa to evaluate whether science underpinned strategic and applied management decisions regarding elephants. We also evaluated their perspectives on limitations to, and opportunities for, greater reliance on science. Twenty-nine managers valued science as a platform for their decisions. However, most managers based decisions on experience-based information. Only 28%, 30% and 8% of managers respectively developed objectives, identified issues and selected management methods on science-based information. Furthermore, only 30% selected a desired number of elephants, and 5% selected a population control method, according to science-based information. The probability of managers basing decisions on science-based information differed with management area size, tenure, planning timeframes and manager experience. However, except for experience, these relationships were weak, and overall an implementation gap between science and elephant management existed. Limitations for science to inform decisions included lack of relevance and application of science findings to respective management areas, and scientists’ attitudes and credibility. Opportunities included more site specific studies, better communication of, and easier access to scientific material. These opportunities could enable scientists to contribute more effectively to elephant management decisions and improve the reliance on science among the wider community of conservation practitioners in Africa.     

Effect of inulin and oligofructose enrichment of the diet on rats suffering thiamine deficiency

Thiamine deficiency resulted in inhibition of two main pathways supplying energy to the tissues: glycolysis and β-oxidation. Glycolysis was found to be inhibited to 40% of initial value calculated on the basis of RBC trans-membrane transport of glucose. Prolongation of experiment cause lowering of uptake of this sugar. In rats, energy production from fatty acids (FA) seems to be less sensitive to thiamine deficiency than glycolysis. After 30 days of feeding, utilization of FA in rats was depressed to the 61% of initial value. Thiamine deficiency suppressed insulin secretion, and the changes were statistically significant. Feeding of rats with thiamine restricted diet for 1 month caused the reduction of serum insulin by 14%. In the same animals, trans-membrane glucose transport was reduced over two-times, what might suggest a decreased efficiency of insulin action in such conditions. The kind and concentration of non-digestible fructo-oligosaccharides (FOS) did not affect significantly serum insulin concentration in animals fed thiamine restricted diet. Substitution of a part of wheat starch with FOS has only insignificant compensatory effect on the uptake of glucose. A partial amelioration of the β-oxidation inhibition caused by feeding rats with thiamine deficient diet was observed in animals supplemented with FOS. However, this effect was statistically significant only in rats receiving diet containing 10% of inulin. The effect of supplemented FOS and their concentration on trans-membrane glucose transport in RBC was statistically significant, when pulled supplementation groups were used for statistical evaluation.     

大中微量元素配施对陇薯5号养分吸收及品质的影响

在陇中高寒阴湿区研究大中微量元素配施对马铃薯陇薯5号NPK吸收规律的影响。研究结果表明,生育阶段不同养分在陇薯5号各器官中的分配比例不同,生育期单株氮磷钾养分吸收速率呈单峰曲线。生育前期吸收的养分主要分配在茎叶中;块茎膨大期,养分在茎叶和块茎中的分配约为8∶2;成熟期,块茎中氮磷钾的比例分别约为50%,65%,60%。出苗后45 d,65~75 d分别是马铃薯陇薯5号P、NK需求关键期。此外,NPK＋微量元素配施可以提高马铃薯块茎干物质、粗淀粉、VC、粗蛋白含量,提高马铃薯产量,说明均衡施肥可实现马铃薯稳产优质。     

The effect of preservatives on water balance in cut clematis flowers

A positive water balance is crucial for longevity of cut shoots. When water loss by transpiration exceeds water uptake by cut flowers, wilting symptoms appear. Clematis is a very attractive plant which can be used as a cut flower provided that suitable cultivars are chosen. The vase life of four cultivars tested ranged between 6.7 days and 9.0 days and the standard preservative – 200 mg·dm^?3 8-hydroxyquinoline citrate (8HQC) plus 2% sucrose – prolonged it significantly in two cultivars, while 8HQC alone was efficient in only one. The preservatives delayed reduction in fresh weight. An enhancement of water uptake by the preservatives resulted in prolonged vase life of flowers in two cultivars. However, the effect of preservatives on transpiration was not related to longevity. In addition, longevity did not depend on the xylem vessel size: the cultivar with the longest vase life had the lowest average xylem vessel diameter while the cultivar with the largest vessels had an intermediate vase life. Preservatives did not always affect the number of blockages in xylem appearing during vase life. Generally, the effects of preservatives on the elements of water balance in cut shoots of clematis were not directly related to the postharvest longevity.