Microscopic observations of bacterial sorption in soil cores

 Bacterial cells may be immobilized in soil through adsorption to a variety of soil particles. These associations affect the interaction of native soil microbes with their nutrient sources and control at least in part the distribution of foreign bacteria entering the soil system. To observe the relationship between soil structure and adsorption of amended bacterial cells, a series of intact cores of Freehold fine sandy loam were inoculated with suspensions of Arthrobacter crystallopoietes cells at concentrations ranging from 10⁶ to 10⁸ cells per ml. The cells were cultivated in a glucose-based medium to induce spherical cell formation. Following inoculation, the soil cores were rinsed with sterile water (30–40 ml h^–1), flushed with thiazine red R to stain the bacterial cells, and then prepared for examination by common micromorphological techniques. The use of fluorescence, polarizing, and reflected light microscopy of soil thin sections, allowed direct, qualitative determinations of microbial distribution and associations with soil components. A. crystallopoietes cells were detected throughout the length of the soil columns. Soil pores did not appear to be clogged by the spherical A. crystallopoietes cells. Adsorption of amended bacteria was governed by the presence of both variably charged mineral oxides and organic matter within the intergrain microaggregates and occurred along coated mineral surfaces. Amendment of non-inoculated soil columns with 0.2% (w/v) solution of glucose demonstrated that the staining and sectioning procedure was sufficiently sensitive to detect growth of indigenous bacterial populations and their distributions within the soil matrix. Received; 6 April 1997     

黄家二岔小流域土壤水分空间分布特征

该文采用定位观测和谐波分析的方法对黄家二岔小流域土壤水分空间分布特征进行了研究．结果表明： 无论何种降雨年型, 流域内中游地段土壤含水量最高, 下游地段土壤含水量高于上游, 坡下部的高于坡上部, 阴坡高于阳坡．     

圆斑星鲽仔稚鱼色素细胞发育和体色变化

为研究圆斑星鲽早期发育过程中色素细胞的形态和分布,实验对1~72日龄的圆斑星鲽鱼苗进行了连续的显微观察,并绘制了早期发育生长曲线。结果显示,圆斑星鲽从20日龄开始进入快速的增长期,在水温12~19.5°C时完成变态发育需要50 d,黑色素细胞最早出现,数量最多,黄色素细胞次之,虹彩细胞最后发育,数量最少。变态前黑色素细胞密度先升高后降低,在9日龄密度最大为1390个/mm~2,色素细胞逐渐密集鱼体两侧对称分布;变态开始后鱼体两侧色素不对称,有眼侧体表黑色素细胞逐渐溶解消退,由成体黑色素细胞代替,体色变深,黑色素细胞密度稳定在150个/mm~2;无眼侧黑色素细胞逐渐消溶退化,体色逐渐变白。白化个体在变态开始后出现,有眼侧不能形成成体黑色素细胞,形成白化。     

凡纳滨对虾越冬亲虾黑鳃病症的初步研究

为确定越冬凡纳滨对虾亲虾黑鳃病症病因,对患病亲虾病因进行分析。结果显示,越冬后患病亲虾鳃部观察到大量线虫。虫体特征显微结构显示,雌、雄性线虫的平均体长分别为(983.6±16.69)μm和(956.9±12.14)μm,虫体表皮不均质,具有2纵列侧分化、4根头刚毛、3个口腔实齿、5个杯形肛前附器,化感器横向扁椭圆形,食道不形成食道球;经鉴定,确定该线虫隶属于色矛科(Chromadoridae)、色矛属(Chromadorella)。组织病理观察结果表明,线虫感染后亲虾鳃组织坏死、溶解,黑色素沉积,游泳足基部出现黑化层。本文报道了一种由色矛线虫引起的越冬亲虾黑鳃病症。     

双吸式离心泵叶片吸力面泥沙磨损破坏规律与形成机制研究

离心泵叶片泥沙磨损是引黄泵站面临的工程难题,采用模型试验及数值模拟相结合的方法,分析了双吸式离心泵叶片出口的磨损破坏规律及其形成机制。采用多层涂层法、丝线法和内窥式成像技术对叶片的磨损特征和近壁面流态进行了分析,并结合数值模拟分析了叶轮流道内的旋涡结构及颗粒轨迹。研究发现：叶片吸力面出口存在左右近似对称的“三角形”磨损破坏区域,该区域存在明显的流动分离;叶轮内的叶道涡和出口回流涡是导致叶片吸力面出口磨损的主要原因。源于叶片压力面进口的叶道涡诱导泥沙颗粒向叶片吸力面出口聚集,造成吸力面出口的集中磨损;叶片吸力面出口附近存在的回流涡诱导颗粒进行轴向旋转运动,加剧叶片吸力面出口的磨损破坏。本研究为双吸式离心泵的抗磨损设计提供了理论支撑。     

四组中药组方治疗绵羊传染性胸膜肺炎效果观察

羊传染性胸膜肺炎又称羊支原体性肺炎,由支原体所引起的一种高度接触性传染病,其临床特征为高热,咳嗽,胸和胸膜发生浆液性和纤维素性炎症,主要危害1～3月龄的羔羊,常呈急性和慢性经过,病死率较高,是绵羊养殖中较为常见的呼吸道疾病。临床上大多采用抗生素进行治疗,但常常发生耐药情况而导致疗效差的情况。近年来,我们采用早期应用中草药辅以较为敏感的抗生素进行治疗,取得了良好的治疗效果。本文就对常用的4组中药组方开展疗效观察,筛选出了一组疗效最佳的中药组方,以期为临床治疗提供解决方案。     

The effects of sperm–egg ratios on polyspermy in the blood clam,Tegillarca granosa

Polyspermy in Tegillarca granosa, which leads to failure or abnormal development of early embryos, appears to be directly related to varying sperm–egg ratios. We investigated the correlation between sperm–egg ratios and conditions of embryonic development by setting six strict sperm–egg ratios and subsequently scoring fertilization rate, abnormal rate, rates of trochophore and D‐shaped larvae. When sperm–egg ratios rose from 2 × 10²:1 to 1 × 10³:1, D‐shaped larvae rate dropped significantly from 78.8 ± 13.3% to 47.8 ± 14.9% (analysis of variance, P< 0.05), and to 3.6 ± 2.8% in the 2 × 10⁴:1 group. Using fluorescence microscope observation, polyspermy rates rose from 2.6 ± 0.8% to 72.9 ± 4.8% with increases in sperm–egg ratios. Sperm–egg ratios were therefore correlated with polyspermy rate, which seriously affected larval survival. Under the premise of higher fertilization rate, the sperm–egg ratios of ≤2 × 10²:1 appeared to be more beneficial for embryonic development of T. granosa.     

滇中地区花椰菜引种观察试验初报

于2006年秋,引进51个花椰菜品种,在昆明市海拔1 920 m的试验地安排花椰菜引种观察试验,试验结果表明,太白、一代神良100天、赛白80、玛瑞亚和白阳5个品种商品性优,产量性状也较理想,抗病性较好,具有良好的推广应用前景,适宜在滇中地区种植,建议参加2007年的品种比较试验.     

能见度自动观测和人工目测的对比分析

通过对能见度人工目测和自动观测方法、观测数据和影响因素的分析,认为自动能见度仪观测到的数据更为客观,更具科学性,避免了人为误差,提高了工作效率。为获得准确的观测数据,应对自动观测仪器按照规范及时进行维护。     

兰州市安宁区桃畸果病病原鉴定和受害桃芽及果实显微组织观察

试验对兰州市安宁区桃畸果病害的发病原因和受害桃芽及果实组织结构变化进行了研究.结果表明:危害兰州市安宁区桃畸果病的病原为下心瘿螨(Eriophyes catacardiae Keifer);瘿螨对桃芽和果实均产生了很大影响,2010年桃芽受害率为52.9%,2011年为61.9%,严重时高达76%.受害桃芽干瘪瘦小,芽鳞片层数增加1~2层,严重的出现芽体坏死现象;对桃芽显微组织观察发现受害桃芽叶原基受损,严重的无叶原基,失去萌芽能力,在芽体鳞片内侧、苞片及幼叶间可见大量的寄生虫体取食为害;对果实形态及组织观察发现,受害果实表面出现不同程度深绿色凹陷,畸形部位桃毛密度和桃毛长度均高于正常果实;显微切片观察表明,受害果实细胞易于染色,细胞排列紧密,畸形果实细胞小于正常果实,畸形果实细胞直径为58μm,正常果实为102μm.