烟草氨基酸代谢及其调控机制

综述了植物氨同化以及烟草中苯丙氨酸代谢、脯氨酸代谢、美拉德反应及其与烟叶风味和品质关系的研究进展,并分析了环境因素对烟草氨基酸代谢的影响,为深入研究氨基酸对烟叶品质和风味影响的机制奠定了基础。     

黄河三角洲台田间渗水池塘的水质变动规律分析

以黄河三角洲地区台田间渗水池塘为研究对象,分析了渗水池塘的水质因子变动规律。结果表明:不同池塘间水质因子差异较大,但均表现出水体盐度较高、氮磷等营养物质含量较低、K+离子含量相对较低、Ca2+离子和Na+离子含量相对较高及K+/Na+显著低于正常海水等特点。结果说明,黄河三角洲地区台田间渗水池塘的水质条件不适合直接进行水产养殖,应对水质调整后才可做养殖之用。     

Relationship between corn yield and chemical composition of the ear leaf measured with different regression models

Abstract

Corn yields and leaf samples were obtained from experimental plots receiving varying rates of N, P and K. Yields were regressed on leaf levels of N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn as independent variables. Various polynomial regressions were fitted to the yields and “goodness of fit”; of particular mathematical models was used as a basis for evaluating particular biological and statistical concepts.

It was found that no regression, where chemical elements were used as ratios, fit the observations as well as a quadratic polynomial or its square root transformation. This suggests that within the set of data used, emphasis on particular cation or anion ratios does not necessarily result in the “best”; explanation of variation in yield.

“Classical”; growth equations were fitted to corn yields, but were not as precise in predicting yields as the polynomials. A modified stagewise regression procedure was used for fitting one mathematical model, but results were less satisfactory than those obtained with usual least squares procedures.     

Use of the nitrate‐specific ion electrode for the determination of nitrate nitrogen in surface and ground water

Abstract

The usefulness of the nitrate‐specific ion electrode (NE) for the determination of nitrate nitrogen (NO3‐N) in surface and ground water was determined. The NE method had several advantages that made it superior to the phenoldisulfonic acid (PDS) method in our environmental quality studies. Samples could be analyzed quickly and with a minimum of sample preparation. Sample coloration and soluble salts did not interfere with the performance of the electrode. Range of detection without dilution was much wider than by the PDS method. Also, the values obtained by the NE method, although slightly greater than those obtained by the PDS method, were satisfactory.     

A Study on the Reduction of Hexavalent Chromium Ion in the Process of Sintering and Ironmaking

The basic principle of using chromium leach residue as melting flux of blast furnace is introduced in this paper.The reduction thermodynamics of Na 2CrO 4 and chromium oxides in the process of sintering and ironmaking is studied,and the simulating experiments in the laboratory and industrial experiments in 600 m 3 blase furnace are carried out.The results of thermodynamical study and experimental study show that hexavalent chromium ion in the burden can be well eliminated in the process of sintering and ironmaking.     

桃铁离子吸收动力学研究

以毛桃幼苗为试材，对不同铁形态、pH值和盐胁迫条件下铁离子吸收动力学特性进行了研究。结果表明，pH是影响铁吸收的主要因素，不同铁形态的有效性随pH的变化而变化；pH和铁形态影响桃铁离子吸收动力学参数Km和Imax；NaCI胁迫对盐敏感性植物（桃）铁吸收特性的影响，可能与质膜透性、载体系统活性以及介质中有效铁含量有关。     

河网水流模拟编程计算研究

以扩展的圣维南方程组和有限差分方程组为基础，对河网进行合理的编码，采用Preissmann法对圣维南方程组进行离散，采用河网矩阵标识法的三级解法编制河网非恒定流的计算程序求解各断面的水位Z和流量Q。     

Estrogen treatment enhances mesenteric lymphatic contractility in rats after hemorrhagic shock

AIM To investigate the effects of 17β-estradiol （E2） treatment on the mesenteric lymphatic microcirculation and isolated lymphatic contractility in rats after hemorrhagic shock, and to explore the relationship between contractility and the difference between intra- and extracellular calcium ion concentrations （［Ca²⁺］） of lymphatic smooth muscle cells （LSMCs）. METHODS Male Wistar rats were divided into sham group, shock group and shock+E2 group. The rats were subjected to hemorrhage ［（40±2） mmHg for 90 min］ and resuscitation with or without subcutaneous injection of E2 （2 mg/kg）. After resuscitation for 3 h, the mesenteric lymphatic microcirculation in vivo was observed. Moreover, the isolated mesenteric microlymphatic rings were prepared for the observations of lymphatic contractility evaluated by the indexes including end-systolic diameter, end-diastolic diameter, contraction frequency （CF） and passive diameter. Meanwhile, the difference between intra- and extracellular ［Ca²⁺］ of LSMCs was recorded during lymphatic contraction. RESULTS Treatment with E2 significantly enhanced the CF, total contractile fraction and lymphatic dynamics index in vivo in the rats after hemorrhagic shock, and increased the CF, the fractional pump flow and the difference between intra- and extracellular ［Ca²⁺］ of LSMCs in isolated lymphatics from the shocked rats （P<0.05）. CONCLUSION Estrogen treatment enhances lymphatic contractility in rats after hemorrhagic shock, which is related to enhancement of difference between intra- and extracellular ［Ca²⁺］ of LSMCs.     

典型旱作农田土壤氧化亚氮排放的氨氧化微生物相对贡献

氨氧化过程对氧化亚氮（N2O）排放具有重要贡献。在不同土壤类型和农田管理下,氨氧化微生物类群对N2O排放的相对贡献组成规律还缺乏系统的研究。本研究选取典型农田耕层土壤（潮土、黑土、砖红壤）,以及有机肥改良的砖红壤剖面土壤,采用选择性抑制法（乙炔和辛炔）研究氨氧化细菌（AOB）、氨氧化古菌和全程硝化菌（AOA+comammox）以及异养硝化菌对土壤硝化潜势、净硝化速率及N2O排放的相对贡献。结果表明,在耕层土壤中,潮土、黑土和砖红壤的pH分别是8.0、6.7和5.7,硝化潜势分别是N 32.5、6.6和4.8 mg?kg-1?d-1,净硝化速率分别是N 7.1、3.0和0.5 mg?kg-1?d-1,7天N2O累积排放量分别是N 38.0、35.4和8.7 μg?kg-1。AOB主导耕层土壤的硝化潜势,对硝化潜势的贡献分别是82%、58%和100%。对于净硝化速率,在潮土和砖红壤中,AOB和AOA+comammox贡献相当（均在30%~40%）,而黑土中由AOB主导（72%）。AOB主导耕层土壤的N2O排放,对N2O排放的贡献分别是72%、92%和58%。在改良的砖红壤剖面土壤中,在0~20 cm、20~40 cm和40~60 cm,pH分别是7.0、5.5和4.9,硝化潜势分别是N 6.6、2.0和1.1 mg?kg-1?d-1,净硝化速率分别是N 4.1、0.9和0.2 mg?kg-1?d-1,N2O排放分别是N 16.3、6.5和2.8 mg?kg-1?d-1。随土壤由深层至表层,硝化潜势、净硝化速率及N2O排放显著提高。AOA+comammox主导表层硝化潜势及净硝化速率的提高（分别贡献63%和54%）,AOB主导N2O排放的增加（贡献54%）。本研究为制定与土壤氨氧化特性及土壤性质相匹配的N2O减排措施提供了新的科学依据。     

离子束注入硅酸盐细菌诱变选育研究

硅酸盐细菌能分解铝硅酸盐类矿物中的钾、磷、硅等元素,直接供植物生长利用。采用低能N离子束注入技术对硅酸盐细菌进行诱变,然后经有氮培养基初筛、缺钾培养基复筛,获得解钾能力强的硅酸盐细菌S-05突变株,扫描电镜观察菌株的形态。进行盆栽试验,研究S-05菌株对水稻根际土壤速效钾含量的影响。结果发现,发酵液50倍稀释处理组速效钾含量最高,比原菌株处理组(CK1)和空白对照组(CK2)分别提高55.79%和260.84%。