金属离子对蜜蜂球囊菌几丁质酶活力的影响

探讨了不同金属离子对蜜蜂球囊菌几丁质酶活力的影响.结果表明:在0-100 mmol.L-1范围内,一价金属离子Na+、K+随离子浓度的增大,对几丁质酶活力的影响表现为先促进后抑制;在1-10 mmol.L-1范围内,二价金属离子Mg2+、Mn2+起抑制作用,Zn2+基本没有影响,Ca2+、Fe2+起促进作用;在1-10 mmol.L-1范围内,三价金属离子A l3+起促进作用,Fe3+基本没有影响.     

NaCl胁迫下苞片对华北驼绒藜种子萌发的影响

对去苞片和带苞片的华北驼绒藜种子在不同的盐浓度下进行处理,带苞片种子的发芽率、发芽指数、活力指数均高于去苞片的。在ＮａＣｌ浓度为７０,１４０,２１０,２８０和４２０ｍｍｏｌ／Ｌ 时,带苞片种子的发芽率显著高于去苞片的（犘＜０．０５）,分别为９０．００％,８９．００％,７９．７５％,６９．２５％,５３．７５％ 和７８．５０％,８１．５０％,７４．００％,６２．２５％ 和３９．２５％。用蒸馏水和４９０ｍｍｏｌ／Ｌ 的ＮａＣｌ溶液对带苞片和去苞片的华北驼绒藜的种子处理１２ｈ,带苞片种子吸水率均低于去苞片的,苞片延缓了种子的吸水率。４９０ ｍｍｏｌ／Ｌ ＮａＣｌ处理华北驼绒藜种子１,３ 和７ｄ后,苞片中Ｎａ＋ 含量显著增加（犘＜０．０５）。说明华北驼绒藜种子的苞片可以吸附一部分Ｎａ＋ ,减少对胚的伤害。苞片对华北驼绒藜在荒漠盐渍环境中的定植具有重要的意义。     

电渗析可变电荷土壤中氢氧根离子的释放与氯离子吸附的关系

The release of hydroxyl ions from two variable charge soils associaed with the adsorption of chloride in NaClO4 solutions was examined.The complete release required about 10 minutes The release decreased with the increase in the NaClO4 concentration at first and eventually was little affected by the latter.The adsorption of Cl^-1 was almost linearly related with the quantity of NaCl added to the system,while the OH^- release-NaCl curve varied with the soil type and the concentration of NaClO4.The logarithm of the quantity of released OH^- was linearly related with the pH ,The ratio of release OH^- to adsorbed Cl^- was larger in dilute NaClO4 solutions than in concentrated solutions and decreased with increasing NaCl.     

聚氯乙烯废料的含量对复合刨花板性能的影响

本研究主要是探求聚氯乙烯废料在复合刨花板中的不同加入量对刨花板物理力学性能的影响。结果表明：随着聚氯乙烯废料加入量的增加,复合刨花板的静曲强度,弹性模量以及内结合强度均降低;吸水厚度膨胀率减小;但振动阻尼系数增大;表面粗糙度也产生一定的变化。在多数情况下板材的物理力学性能可以达到日本ＪＩＳ Ａ ５９０８刨花板标准的要求,这说明在板中加入适量的聚氯乙烯废料可以生产出具有优良性能的刨花板。     

马铃薯晚疫病菌基因文库的构建

用酶一氯化苄法制备高分子量晚疫病菌总ＤＮＡ,通过Ｓａｕ３Ａ部分酶切并纯化后得到１５－２５ｋｂ的酶切片段,并以具有广寄主范围的柯斯质粒ＰＬＡ２９１７为载体,用Ｔ４ＤＮＡ连接酶连成为重组ＤＮＡ,包装到入噬菌体颗粒中,转染受体菌Ｅ．ｃｏｌｉＳ１７－１。利用四环素和卡那霉素抗性来筛选鉴定重组子,得到１０６５６个重组子,这些重组子群即为晚疫病菌的基因组文库。     

离子注入甜菊的诱变效应研究

用７５ｋｅＶ的氮和碳离子的不同剂量注入甜菊干种子,以γ射线作对比,研究其Ｍ１生物学效应和Ｍ２突变。结果表明,离子术能诱发甜菊染色体结构的变异,染色体畸变细胞率随离子注入剂量的提高呈增加趋势。离子束对甜菊的Ｍ１损伤效应低于γ射线,而诱发的Ｍ２突变高于γ射线。碳离子诱发的染色体畸变细胞率和Ｍ２有益性状突变高于氮离子。离子注入杂交一代丰１×日原和日原×丰２的诱变效应大于济宁种和丰２。     

Susceptibility of channel catfish (Ictalurus punctatus) fed with dietary sodium chloride to nitrite toxicity

Juvenile channel catfish (Ictalurus punctatus) were fed with nutritionally complete, basal diets supplemented with NaCl at 0, 10, 20 or 40 g kg^?1 diet (0, 1, 2, or 4%) to apparent satiation twice daily for 10 weeks. Catfish were exposed to nitrite after six (7.70 mg L^?1 nitrite‐N) and ten (7.18 mg L^?1 nitrite‐N) weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were sampled before (baseline, pre‐exposure) and after 24‐h nitrite exposure to determine the effects of dietary NaCl on haematology (haematocrit, haemoglobin and methaemoglobin) and plasma electrolyte dynamics (nitrite, chloride, sodium and potassium). Mortality from nitrite toxicity was also determined. Mortality from nitrite exposure tended to decrease with increasing NaCl in the diet at 6 weeks and was significantly lower in the 40 g kg^?1 NaCl group (12.5%) compared to the control group (57.5%). A similar trend in mortality occurred at 10 weeks as well; however, the differences among dietary treatments were not significant. The improvements in blood MetHb (non‐significant), chloride and nitrite levels in catfish may at least in part be responsible for the improved survival after nitrite exposure, which trended in support of the prevailing hypotheses for the positive effects of NaCl on nitrite toxicity.     

Effect of cadmium on the cytoskeleton and morphology of gill chloride cells in parr and smolt Atlantic salmon (Salmo salar)

This study documented the effect of cadmium on salmon parr and smolt gill morphology. Cadmium-induced changes in chloride cell (CC) cytoskeletal elements were investigated, as well as the modifications of CC surface area and density. In cadmium-treated parr (10 µg Cd l^-1 for 2 days), immunofluorescent light microscopy revealed the appearance of an intense actin staining located in the CC apical part. Transmission electron microscopic observations revealed a change in the organization of the microfilaments at the CC apex, with the appearance of numerous aggregates of filamentous actin. Higher cadmium concentrations (30 and 50 µg l^-1) and prolonged treatment times (7 to 14 days) did not modify such reorganisation. Microtubules were not significantly affected by similar treatments. Further, scanning electron microscopic analysis revealed that cadmium induces a significant increase of parr CC surface area as early as the second day of exposure. After 2 days, mature CC density had also increased. In smolt, a rise in CC surface area was observed, although CC density did not significantly increase.     

Pyrite oxidation in sediment samples from the German open‐cut brown coal mine Zwenkau: mineral formation and dissolution of silicates

Changes in mineral composition occurring in pyrite‐containing sediments under aerobic conditions are complex and not fully understood. The objective was to study the mineral formation and dissolution of silicates using ion activity product (IAP) calculations and x‐ray diffraction (XRD) on samples of different degrees of pyrite oxidation. Three sediment samples were obtained from the open‐cut brown coal mine of Zwenkau (Saxony, Germany) with low (ZL: 28 g kg^—1), medium (ZM: 67 g kg^—1) and high (ZH: 95 g kg^—1) pyrite contents. These samples were oxidized in the laboratory for 3, 20, 67, and 130 days to obtain four different degrees of pyrite oxidation for each sediment. Sequential batch experiments were carried out for each sediment and oxidation status. Additionally, cation exchange capacities were determined. XRD showed the formation of gypsum (all sediments), jarosite (ZM, ZH), and rozenite (ZH) with increasing pyrite oxidation. IAP calculations suggested an occurrence of gypsum in all samples, of schwertmannite in slightly (ZH) and moderately oxidized (ZM, ZL) samples, and of alunite in a moderately oxidized sample (ZL). The contents of feldspar (ZL), mica/illite (ZL, ZH), and kaolinite (ZH) decreased with increasing pyrite oxidation. The cation exchange capacities of the sediments decreased by 20 (ZH) to 70 mmol_c kg^—1 (ZM). The change in mineral phases with increasing oxidation status of the sediments also changed the activities of Al, Fe, and SO₄ in solution phases. The results obtained in this study suggested the usefulness of predictive models to estimate sediment and water acidification due to pyrite oxidation.     

重离子束在玉米诱变育种中的应用研究

为扩大玉米种质资源,用重离子^7Li和^12C分别辐照玉米品种农大108种子胚,研究重离子束辐照玉米种子的诱变效应.结果表明：所用能量和剂量的重离子^7Li和^12C对M1出苗率影响不明显;重离子辐照后,M1代产生了5株黄化苗,6株雄性不育,2株无雄穗,1株抽雄期提早等多种变异植株、M2代获得了多穗玉米突变类型．变异材料可供进一步选择．