井冈霉素对水稻纹枯病菌生长发育的影响 

以水稻纹枯病菌(Rhizoctonia solani Kühn)强致病菌株GD-118为供试菌株,在室内观察了井冈霉素(Jinggangmycin)对其生长发育的影响。结果表明:井冈霉素对水稻纹枯病菌的毒力回归方程为y=3.360 3+1.320 4x,相关系数r=0.962 6,理论抑制菌丝生长的EC50为70.2μg/mL,EC95为6 341.5μg/mL。与不加井冈霉素的空白对照相比,用井冈霉素处理后水稻纹枯病菌的菌落边缘明显凹凸不平,边缘菌丝更密集、颜色加深,并且随着井冈霉素处理浓度的增加,菌丝的干质量逐渐降低,但菌落表面菌丝的密集程度有所增加、颜色更深;空白对照的菌核呈颗粒状、褐色,散生于菌落表面,边缘较多而中间较少;用井冈霉素处理后的菌核多数为粉状、浅褐色,部分菌核会连在一起呈块状,分布在菌落外围呈明显的双环形,具不规则的凹凸型菌落边缘,并且随着井冈霉素处理浓度的增加,菌核的干质量有所增加,菌核出现时间比空白对照提前约24h。另外,随着井冈霉素处理浓度的增加,水稻纹枯病菌的菌丝细胞核平均数目和分布范围均有不正常增多的趋势。     

酵母诱导表达鸡IFN-α抗IBDV效果及其对信号分子PI3K和NF-κB的影响

试验旨在研究酵母表达鸡IFN-α抗传染性法氏囊病病毒（IBDV）的效果及对其淋巴细胞信号分子PI3K和NF-κB p65的影响。将40只10日龄非免疫雏鸡随机分为IFN-α组和空白对照组,持续注射给药3 d后,于第3次给药后第1天开始每天心脏采血,持续3 d,并于最后一次采血后对雏鸡进行攻毒,在攻毒后开始每天心脏采血,连续3 d。通过MTT法检测淋巴增殖活性情况,ELISA测定不同时间段淋巴细胞中PI3K的水平、细胞中总NF-κB p65、细胞核中NF-κB p65蛋白表达含量及IBDV抗原量。结果显示,与对照组相比,攻毒前,IFN-α对淋巴增殖活性、细胞中PI3K和NF-κB p65的表达具有极显著地促进作用（P<0.01）;与攻毒前相比,攻毒后第1和2天IFN-α组淋巴增殖活性、细胞中PI3K和NF-κB p65的表达极显著增加（P<0.01）,IFN-α对IBDV-Ag具有极显著地抑制效果（P<0.01）。这些结果表明,IFN-α可通过增加PI3K激活NF-κB信号通路以增强机体免疫反应,并对IBDV-Ag有显著的抑制作用,本试验为IFN-α免疫增强和抗病毒作用的研究提供科学依据。     

3种家蚕30K蛋白基因的克隆表达及抗凋亡功能分析

业已明确家蚕30K蛋白不仅作为家蚕生长发育的重要能源物质,还对细胞凋亡具有明显的抑制作用。采用RT-PCR技术从家蚕5龄幼虫脂肪体中克隆了BmLp-C6、BmLip19G1和BmLp-C12p(GenBank登录号分别为X54735、AY568957、NM_001101728)共3种30K蛋白基因的cDNA序列,并利用Bac-to-Bac系统构建含有3种30K蛋白基因的重组杆状病毒表达载体,转染家蚕BmN培养细胞大量表达3种30K蛋白,3种表达产物纯化后的样品经SDS-PAGE检测到明显的30 kD大小的目的蛋白条带,Western blotting分析3种纯化后的蛋白样品与6×His-tag抗体具有良好的特异性反应。纯化后检测3种表达产物对诱导凋亡的抑制作用。经MTT法检测3种纯化30 K蛋白可明显增强过氧化处理的人血管内皮原代培养细胞(EC)的活力,采用ELISA法检测3种纯化30K蛋白能明显减缓EC细胞中的DNA片段化,显示3种30K蛋白对H2O2诱导的EC细胞的凋亡均具有一定的抑制作用。用生物信息学方法预测3种家蚕30K蛋白的氨基酸序列相似性达43%,三级结构极其相似,推测3种蛋白具有相似的生物学功能。     

氮磷钾与锌肥配合施用对土壤和植株养分含量的影响

采用大田长期肥料定位试验,研究了氮磷钾与锌肥长期配合施用对小麦和玉米产量以及土壤肥力的影响。结果表明：连续5a均衡施肥可以显著提高土壤全氮、全磷、速效氮、有效磷等肥力指标,显著提高小麦,和玉米产量。与氮磷钾配合施用相比,氮磷钾与锌肥长期配合施用能显著提高土壤有效锌含量,以及小麦和玉米植株的锌含量;而连续5a不均衡施肥会导致土壤中某些营养元素耗竭或累积,并使小麦和玉米产量显著降低。长期均衡施肥可以基本维持土壤肥力,并保证小麦和玉米稳产。     

江西省红壤旱地土壤钾素含量分布研究

本项研究对江西省五种主要成土母质发育的红壤旱地土壤，按土属布点，共取表层土样２４８个，剖面样７５个，分别测定了全钾、缓效性钾和速效钾含量，查明了全省红壤旱地土壤全钾、缓效性钾、速效性钾含量平均分别为１６．７ｇｋｇ￣（－１）±７．３ｇｋｇ￣（－１）、２５１．９ｍｇｋｇ￣（－１）±１４５．９ｍｇｋｇ￣（－１）和６３．９ｍｇｋｇ￣（－１）±３２．４ｍｇｋｇ￣（－１），低于缺乏临界水平（速效性钾＜７０ｍｇｋｇ￣（－１）的样品占７９．５％。阐明了不同成土母质发育的红壤旱地颖型间的钾素含量的差异，以及影响钾素含量的因素有母质、含钾矿物、有机质、质地和粘粒。绘制出土壤缓效性钾、速效性钾含量分布图为红壤旱地土壤资源评价和合理施用钾肥提供了依据。     

N、P、K配方施肥对1年生黄芩生长的影响

[目的]研究N、P、K配方施肥对1年生黄芩生长的影响。[方法]采用3因素2次D-饱和度最优试验,考察N、P、K配比对黄芩生长的影响,筛选出商洛黄芩的最佳施肥方法。[结果]各施肥处理中,黄芩各项指标均高于空白对照组,说明3种元素的配合施用有助于黄芩的生长。总体上看,N、P、K 3种元素配合施用的处理组要优于2种元素配比,更优于单质元素处理组。优选出的最佳的施肥条件为N 79.41 kg/hm2、P2O5 150.00 kg/hm2;在此条件下,黄芩多糖的含量为7.4%。[结论]优选出了最佳施肥方法,为黄芩的生产提供了依据。     

Influence of Aluminum Hydroxide on Potassium Release from Two Colombian Soils

Abstract

The effect of sesquioxides on the mechanisms of chemical reactions that govern the transformation between exchangeable potassium (Kex) and non‐exchangeable K (Knex) was studied on acid tropical soils from Colombia: Caribia with predominantly 2∶1 clay minerals and High Terrace with predominantly 1∶1 clay minerals and sesquioxides. Illite and vermiculite are the main clay minerals in Caribia followed by kaolinite, gibbsite, and plagioclase, and kaolinite is the major clay mineral in High Terrace followed by hydroxyl‐Al interlayered vermiculite, quartz, and pyrophyllite. The soils have 1.8 and 0.5% of K₂O, respectively. They were used either untreated or prepared by adding AlCl₃ and NaOH, which produced aluminum hydroxide. The soils were percolated continuously with 10 mM NH₄OAc at pH 7.0 and 10 mM CaCl₂ at pH 5.8 for 120 h at 6 mL h^?1 to examine the release of Kex and Knex. In the untreated soils, NH₄ ⁺ and Ca²⁺ released the same amounts of Kex from Caribia, whereas NH₄ ⁺ released about twice as much Kex as Ca²⁺ from High Terrace. This study proposes that the small ionic size of NH₄ ⁺ (0.54 nm) enables it to enter more easily into the K sites at the broken edges of the kaolinite where Ca²⁺ (0.96 nm) cannot have access. As expected for a soil dominated by 2∶1 clay minerals, Ca²⁺ caused Knex to be released from Caribia with no release by NH₄ ⁺. No Knex was released by either ion from High Terrace. After treatment with aluminum hydroxide, K release from the exchangeable fraction was reduced in Caribia due to the blocking of the exchange sites but release of Knex was not affected. The treatment increased the amount of Kex released from the High Terrace soil and the release of Knex remained negligible although with Ca²⁺ the distinction between Kex and Knex was unclear. The increase in Kex was attributed to the initially acidic conditions produced by adding AlCl₃ which may have dissolved interlayered aluminum hydroxide from the vermiculite present, thus exposing trapped K as exchangeable K. The subsequent precipitation of aluminum hydroxide when NaOH was added did not interfere with the release of this K, and so was probably formed mostly on the surface of the dominant kaolinite. Measurement of availability of K by standard methods using NH₄ salts could result in overestimates in High Terrace and this may be a more general shortcoming of the methods in kaolinitic soils.     

K6Nb10.8O30对微囊藻毒素的光催化降解研究

通过合成含铌类复合氧化物光催化剂,开展其光催化降解藻毒素试验,研究其光催化降解微囊藻毒素的降解效率和机理,为去除水体中微囊藻毒素提供高效环保的水处理技术。采用溶胶凝胶法制备了铌酸盐光催化剂K6Nb10.8O30,利用X射线衍射、扫面电镜、紫外可见漫反射光谱等对光催化剂进行了结构表征,该化合物结构是属于四方相钨青铜结构,空间群为P4/mbm（127）,晶粒呈长方柱性,直径约为150nm,长度约400～600nm,吸收能带为2.92eV;在紫外光（UVA）辐照条件下,考察了催化剂对微囊藻毒素（MC-LR）的光催化降解效果,利用高效液相色谱测定水体中微囊藻毒素浓度。结果表明,光催化剂K6Nb10.8O30能够有效的降解藻毒素,降解过程受到pH值、藻毒素的初始浓度、催化剂投加量和光照的影响;在光辐射强度为556μW/cm2、pH4.24、催化剂投加量为0.375g/L的试验条件下,初始浓度3mg/L的藻毒素在180min之内降解率达到93%;对催化剂反应前后的红外光谱分析表明,藻毒素的降解最终不是被催化剂吸附,而是被光催化降解;动力学研究表明,微囊藻毒素的光催化剂降解反应符合一级反应动力学规律,随着微囊藻毒素初始浓度的增大,反应速率常数逐步降低,半衰期也逐渐变长。     

Erosion processes and erodibility of cultivated soils in North Rhine‐Westphalia under artificial rain. II. Results of field experiments and comparison with laboratory trials

In the densely populated state of North Rhine‐Westphalia, soil erosion by water causes substantial on‐site degradation and off‐site damages. The implementation of soil‐conservation measures is improved, if soil erodibilities and erosion processes are known. In a state‐wide investigation, we aimed to representatively assess soil‐erosion processes and erodibilities of cultivated soils. For this purpose, we measured surface runoff and soil‐loss rates of 28 cultivated soils with field plots under artificial rain. In the field experiments, surface runoff and soil loss indicated high sealing susceptibilities and high erodibilities on soils of quite different textures including a clay silt, a loam silt, a loam sand, a sand loam, and two standard loams. Rill formation causing high soil‐loss rates was observed on a clay silt (soil BM) and on a loam silt (soil RB), the latter yielding an empirical K‐factor of 1.66 t ha^–1 h N^–1. K‐factors of other silty soils ranged from 0.04 to 0.48, whereas sandy soils and clayey soils had K‐factors ranging from 0.00 to 0.32, and 0.00 to 0.12, respectively. Comparatively high erodibilities of two silt clays were due to saturation overland flow. Erosion processes and erodibilities of soils with similar texture varied to a large extent, possibly caused in part by seasonal differences in the timing of erosion tests. Surface runoff was different in field experiments compared with laboratory experiments (companion paper) conducted with topsoil material taken from the field plots. In addition, higher concentrations of suspended sediment were recorded on average in the field than in the laboratory. These differences might reflect the influence of the subsoil and are due to higher transport capacities on longer plots in the field. Thus, laboratory experiments can complement but not replace costly field trials for K‐factor determination. Empirical K‐factors derived from field and laboratory experiments are in general lower than K‐factors of other soils in Germany or calculated K‐factors derived from pedotransfer functions, which might be attributed to a more maritime‐type climate in North Rhine‐Westphalia. Since the temporal variability of erodibility was not assessed, the reported K‐factors should be regarded as preliminary.     

按最佳传动角参数化快速设计K=1的曲柄摇杆机构

针对K=1这一特殊形式的曲柄摇杆机构，根据其特征及杆件间关系，利用图形化计算分析（Microsoft Student Graphing Calcultor，MSGC）软件可以快速获得满足设计要求的解析解．解决了用几何法设计无法综合考虑最佳传动角，而用解析法设计其求解计算又复杂的问题，为该类机构的设计提供了一种简捷的方法．