Cells of the connective tissue differentiate and migrate into pollen sacs

In angiosperms, archesporial cells in the anther primordium undergo meiosis to form haploid pollen, the sole occupants of anther sacs. Anther sacs are held together by a matrix of parenchyma cells, the connective tissue. Cells of the connective tissue are not known to differentiate. We report the differentiation of parenchyma cells in the connective tissue of two Gordonia species into pollen-like structures (described as pseudopollen), which migrate into the anther sacs before dehiscence. Pollen and pseudopollen were distinguishable by morphology and staining. Pollen were tricolpate to spherical while pseudopollen were less rigid and transparent with a ribbed surface. Both types were different in size, shape, staining and surface architecture. The ratio of the number of pseudopollen to pollen was 1:3. During ontogeny in the connective tissue, neither cell division nor tetrad formation was observed and hence pseudopollen were presumed to be diploid. Only normal pollen germinated on a germination medium. Fixed preparations in time seemed to indicate that pseudopollen migrate from the connective tissue into the anther sac.     

固化法处理废干电池

介绍了电池的历史及其生产的现状、排废特征 ;简述了废旧干电池对环境的危害及其回收处理工艺和经济环境效益 ;结合金霸王 (中国 )有限公司废干电池的特点和电池废料的处理现状 ,对其采用固化法处理 ,然后进行渗漏试验并作出结果分析和评述 ;最后对废干电池的回收处理提出建议。     

对COD_(Cr)测定中干扰因素及其消除方法的探讨

针对CODCr测定中,对消除氯离子、亚硝酸根、亚铁离子和硫离子等干扰因素进行分析探讨,结果表明,所采用方法科学、可靠,并可以获得满意的结果。     

淮河流域多闸坝河流COD综合衰减系数测算

提出在多闸坝河流上，利用枯水期断面化学需氧量同步监测数据测算COD综合衰减系数的方法，用该方法测算河南省辖河流域部分河流COD综合减系数在0．08－0．341/d。并用实际监测结果进行检验。     

化纤废水中污染物对大型溞(Daphnia magna)繁殖的影响

为研究化纤工业对水域生态的长期效应, 首次在实验室研究了化纤工业废水中主要污染物乙醛、对苯二甲酸、乙二醇对大型(Daphnia magna)生殖周期和繁殖数量的影响.实验结果表明, 乙醛浓度低于6 mg/L 时, 对大型溞首次和第二次生殖周期无影响.7～10 mg/L时, 使首次生殖周期推迟1～2d, 使第二次生殖周期提前1～2d.对苯二甲酸浓度32 mg/L以下时, 对首次和第二次生殖周期基本无影响; 64～256 mg/L时, 使首次生殖周期均推迟1～2d, 第二次生殖周期均缩短1～2d.乙二醇浓度在1000 mg/L以下时, 对首次生殖周期无影响; 2000～4000 mg/L时, 推迟首次生殖周期1d; 浓度低于4000 mg/L时, 对第二次生殖周期无影响.乙醛浓度在5 mg/L以下时, 对首次和第二次繁殖数量无显著影响, 浓度在6～10 mg/L时, 显著降低其繁殖数量, 分别降低38.3%～74.1%和12.8%～65.3%.对苯二甲酸浓度低于32 mg/L时, 对首次繁殖数量无显著影响, 浓度在64 ～256 mg/L时, 降低首次繁殖数量62.9%～75.3%; 浓度低于16 mg/L时, 对第二次繁殖数量无显著影响, 浓度在32～256 mg/L时, 使第二次繁殖数量降低37.8%～78.1%.乙二醇浓度在500 mg/L以下时, 对首次和第二次繁殖数量均无显著影响, 浓度在1000 ～4000 mg/L时, 显著降低首次和第二次繁殖数量, 分别降低32.3%～77.8%和42.2%～60.9%.     

城市污水高效低耗生物脱氮工艺研究

采用活性污泥与生物膜法相结合工艺处理城市生活污水，可以高效去除污水中的有机物和NH4^ -N。研究结果表明：水力停留时间为7．5h、回流比为1．5、无外加碳源时，COD的去除率大于90％，NH4^ -N的去除率大于99％；平均出水COD小于40mg／L，NH4^ -N小于1mg／L，TN的去除率60％左右；反硝化过程的适宜C／N为4～5。     

水解酸化＋两级生物接触氧化处理高盐度水产品加工废水

介绍了“水解酸化＋两级生物接触氧化”处理水产品加工废水的运行效果和工程实例，结果表明：对C1^-浓度平均6000mg／L的高盐度水产品加工废水，系统对COD、SS、氨氮的去除率分别超过了88％、90％、85％，出水COD、SS、氨氮分别低于100mg／L、70mg／L、15mg／L，出水完全可以达到《污水综合排放标准》（GB8978—1996）一级排放标准。     

The functionality of female reciprocal calls in the Iberian midwife toad (<Emphasis Type="Italic">Alytes cisternasii</Emphasis>): female-female acoustic competition?

Female midwife toads (genus Alytes) emit highly variable reciprocal calls of unclear function prior to and during courtship. In some species, female-female competition, expressed as physical fighting, has been reported. Males of Majorcan midwife toads (Alytes muletensis) show phonotactic response to female calls, and females of Iberian midwife toads (Alytes cisternasii) respond differently according to the male call characteristics. In this study, I test the hypothesis of female-female acoustic competition as an additional function of female reciprocal calls. Playback tests indicate that female calls are not clearly involved in female acoustic competition in the Iberian midwife toad, therefore female calls could be directed at males rather than towards competitive females.     

浅析机动车尾气污染成因及对人体健康的影响

机动车工作时,由于燃烧不完全等原因,会生成和排出CO、HC、No_x和颗粒物等污染物,对人体的呼吸系统和心血管系统造成危害。应从政策法规、监测监督和舆论宣传3个方面着手加以整治。