重金属污染黑土中固氮菌及反硝化菌作用强度的测定

本文采用气相色谱法同时测定了重金属Cd、As、Pb和Cu污染黑土中固氮菌及反硝化菌的作用强度。为准确、快速地提出土壤中Cd、As、Pb和Cu等重金属毒害土壤微生物临界指标开辟了新的途径。     

一种制备植物扫描电镜样品的新干燥法：叔丁醇冻结干燥法

叔丁醇冻结干燥法用于植物材料,获得了良好的效果。经常规固定的样品完成脱水以后浸泡在叔丁醇中,然后将含醇样品放入电冰箱中冷冻,待叔丁醇凝固后再转移到真空镀膜机的钟罩里,用机械泵抽真空,冻结的醇在低真空中升华后样品得到了干燥。SEM 镜检表明,样品的表面和细胞断裂面及其深层(可见到内质网的双层膜、线粒体的嵴、高尔基体潴泡叠层、核糖体颗粒等细胞器)的三维图象均优于用临界点干燥法所得到的样品图象,叔丁醇冻结干燥法用于植物 SEM 样品制备,是一种操作简单,干燥质量可靠、值得推广的方法。     

藏东南色季拉山林线过渡带7种灌木植物的叶氮回收潜力

在湿润的青藏高原东南部, 为什么常绿灌木广泛占据高海拔的林线过渡带及以上的高山带, 而落叶灌木只能零星分布?未来气候变暖对该区不同功能群物种的影响是否相同?通过测定西藏东南部色季拉山林线过渡带7种灌木凋落叶的氮含量, 比较了极端高海拔地区灌木不同表达单位的叶氮回收潜力在不同功能群间的差异, 以及不同海拔、不同坡向间的差异, 试图从养分限制的角度为解答上述科学问题提供基础数据。研究结果表明: 1)从基于单位质量叶氮含量(N_mass)的叶氮回收潜力来看, 常绿灌木裂毛雪山杜鹃(薄毛海绵杜鹃) (Rhododendron aganniphum var. schizopeplum)显著高于其他6种落叶灌木, 但由于受比叶重的影响, 基于单位面积叶氮含量(N_area)的叶氮回收潜力则表现为落叶灌木总体较高; 2)落叶灌木山生柳(Salix oritrepha)和拉萨小檗(Berberis hemsleyana)的叶氮回收潜力在不同海拔或不同坡向间均无显著差异, 但裂毛雪山杜鹃基于N_mass的叶氮回收潜力在高海拔地段明显偏高。在极端高海拔的林线过渡带, 通过降低凋落叶中的氮含量(增加叶氮回收潜力)以达到高效的养分利用可能是常绿灌木裂毛雪山杜鹃适应高寒胁迫环境的重要策略。与落叶灌木相比, 常绿灌木裂毛雪山杜鹃叶氮回收潜力对未来气候变暖可能更敏感。     

Combined effects of climate and biotic interactions on the elevational range of a phytophagous insect

1. The ranges of many species have expanded in cool regions but contracted at warm margins in response to recent climate warming, but the mechanisms behind such changes remain unclear. Particular debate concerns the roles of direct climatic limitation vs. the effects of interacting species in explaining the location of low latitude or low elevation range margins. 2. The mountains of the Sierra de Guadarrama (central Spain) include both cool and warm range margins for the black-veined white butterfly, Aporia crataegi, which has disappeared from low elevations since the 1970s without colonizing the highest elevations. 3. We found that the current upper elevation limit to A. crataegi's distribution coincided closely with that of its host plants, but that the species was absent from elevations below 900 m, even where host plants were present. The density of A. crataegi per host plant increased with elevation, but overall abundance of the species declined at high elevations where host plants were rare. 4. The flight period of A. crataegi was later at higher elevations, meaning that butterflies in higher populations flew at hotter times of year; nevertheless, daytime temperatures for the month of peak flight decreased by 6.2 degrees C per 1 km increase in elevation. 5. At higher elevations A. crataegi eggs were laid on the south side of host plants (expected to correspond to hotter microclimates), whereas at lower sites the (cooler) north side of plants was selected. Field transplant experiments showed that egg survival increased with elevation. 6. Climatic limitation is the most likely explanation for the low elevation range margin of A. crataegi, whereas the absence of host plants from high elevations sets the upper limit. This contrasts with the frequent assumption that biotic interactions typically determine warm range margins, and thermal limitation cool margins. 7. Studies that have modelled distribution changes in response to climate change may have underestimated declines for many specialist species, because range contractions will be exacerbated by mismatch between the future distribution of suitable climate space and the availability of resources such as host plants.     

长白山三种赤杨根瘤内Frankia基因多样性的REP分析

利用REP PCR方法研究了长白山不同海拔处 3种赤杨根瘤内Frankia菌基因多样性。结果表明 ,赤杨根瘤内Frankia菌存在丰富的基因多样性。宿主和海拔因素共同影响长白山赤杨属Frankia菌的基因多样性 :东北赤杨Frankia菌的宿主专一性很强 ,西伯利亚赤杨和色赤杨的Frankia菌的有较近的亲缘关系。不同海拔的同种宿主共生的Frankia菌基因类型不同 ,相同海拔的西伯利亚赤杨和色赤杨的Frankia菌出现宿主混乱现象     

Contrasting patterns in local and zonal family richness of stream invertebrates along an Andean altitudinal gradient

1. Describing and understanding patterns in biological diversity along major geographical gradients is an important topic in ecology. Samples collected from a large number of physically and chemically comparable stream sites along a 4000 m gradient of altitude in the Andes of Ecuador served to characterise patterns of family richness of aquatic macroinvertebrates at the scale of the stream site (local) and at that of discrete altitudinal zones. 2. Both mean local and zonal family richness decreased by about 50% from sea level to 4000 m a.s.l. Local richness declined linearly, while zonal richness remained constant from sea level up to a threshold altitude of about 1800 m, whereafter it decreased. 3. From sea level to 1800 m few families were lost from zonal richness and few were gained. From 1800 to 3800 m the decrease in the number of families was accounted for by a loss of families present in lowland streams, with few new families gained. Hence, there was relatively little turnover of families along the entire gradient. 4. The diverging pattern of local and zonal richness was caused by sporadically occurring families inflating zonal richness at mid‐altitudes. If the sporadic families were represented by the same species found commonly in the lowlands, then the mid‐altitudinal zonal richness would be maintained by a ‘rescue effect’. More probably, however, the sporadically occurring families found at mid‐altitudes are each represented by new species replacing each other along the gradient, the families progressively diminishing in species richness and occurrence as the overall temperature tolerance of the family is approached. 5. This study demonstrates that spatial scale affects altitudinal patterns in the taxonomic richness of stream invertebrates. It also showed that family‐level identification can facilitate interpretation of sources and sinks of biodiversity along geographic gradients.     

Changes of microcirculation in healthy volunteers and patients with septic shock in Xining

Objective: The purpose of this study is to investigate the characteristic of microcirculation in healthy volunteers and patients with septic shock in both Xining(2 260 m) and Nanjing(10 m). Methods: A total of 62 cases, 33 healthy volunteers, 22 cases in Xining,(2 260 m above sea level) and 11 cases in Nanjing(10 m above sea level); and 29 septic shock, 13 cases in Xining and 16 cases in Nanjing were collected. The total vessel density(TVD), perfused vessel density(PVD), proportion of perfused vessel(PPV) and microcirculation flow index(MFI) of both healthy volunteers and septic shock had been investigated by using sidestream dark field(SDF). Analyzed and managed the image data by using AVA3.0 software. Results: In the healthy volunteers in Xining area(22 cases),the volume of TVD(15.59 ± 2.58 mm/mm~2), PVD(15.58 ± 2.58 mm/mm~2) and PPV(96.60% ± 4.63%) were significant higher than the volume of TVD(10.0 ± 2.10 mm/mm~2), PVD(10.81 ± 2.38 mm/mm~2) and PPV(84.24% ± 8.00%) of the volunteers(11 cases) in Nanjing(11 cases). But the MFI(2.17 ± 0.31) of the healthy volunteers in the Xining was significant lower(P0.05) than the MFI(3.21 ± 0.34) in the healthy volunteers of Nanjing. In the septic shock group(13 cases) in the Xining, the volume of TVD(5.44 ± 1.94 mm/mm~2), PVD(4.18 ± 1.61 mm/mm~2), PPV(42.14%± 5.38%) and MFI(1.05 ± 0.32) compared with the volume of the healthy volunteers in Xining, the TVD(15.59 ± 2.58 mm/mm~2), PVD(5.58 ± 2.58 mm/mm~2), PPV(96.60% ± 4.63%) and MFI(2.17 ± 0.30) were significant lower(P0.05). In the healthy volunteers compare with septic shock group in Nanjing area, the TVD(6.80±1.72 vs 10.00±2.10, P0.05), PVD(5.86±1.58 vs10.81±2.38,P0.05), PPV(45.42±4.86 vs 84.24±4.86, P0.05), MFI(1.28±0.28 vs 3.21±0.34 P0.05), there was significant decreased. In the septic shock group in the Xining compared with the septic shock in Nanjing, there was no significant difference. 10 of 13 patients with septic shock were survived in Xining. 13 of 16 patients with septic shock were survived in Nanjing. Conclusion: The changes of physiological and pathophysiological characteristic in microcirculation induced by hypoxia would be useful for clinical treatment of septic shock at high altitude.     

白龙江干旱河谷不同坡向主要灌丛群落随海拔梯度变化的物种多样性研究

采用样方调查法,研究了白龙江干旱河谷不同坡向主要灌丛群落沿着海拔梯度的结构特征、物种多样性的变化规律,旨在了解白龙江干旱河谷不同海拔梯度植被特征和物种多样性变化,为白龙江干旱河谷区域不同海拔植被恢复提供理论依据。研究结果表明：（1）不同海拔梯度同一坡向物种数不同,同一海拔不同坡向物种数也不同,随着海拔的升高不同坡向物种数表现为先增加后减少的趋势,同一海拔梯度内不同坡向主要植被类型也不同。（2）主要灌木群落α多样性在不同坡向随着海拔梯度的升高,表现出先升高后减小的趋势。不同坡向草本群落α多样性随着海拔的升高,也表现出先升高后减小的趋势。对主要灌丛α多样性指数进行相关性分析得物种丰富度指数对物种多样性贡献率最大,表现为丰富度指数（D₁、D₂）> 生态优势度指数（SN）> 种间机遇指数（H）> 群落均匀度指数（R）。（3）不同坡向主要灌丛群落β多样性Whittaker指数沿着不同海拔梯度变化不大,最大值出现在海拔1250~1650m;Routledge和Codyβ多样性指数在海拔1450~1650m出现最大值,但是大体呈现出波形变化。草本β多样性随着海拔的升高变化较大,阳坡植物的β多样性指数在海拔1050~1250m达到最大,阴坡和半阴半阳坡在海拔区间1250~1450m达到最大,半阴半阳坡的β多样性指数均大于阳坡。白龙江干旱河谷不同坡向、不同海拔梯度物种α多样性和β多样性都不同,且不同坡向随着海拔梯度的变化物种α多样性和β多样性呈一定的相关性,说明海拔和坡向是影响生物多样性主要因子之一。     

急性高原病的遗传易感性

急性高原病(Acute high altitude disease, AHAD)分为急性高原反应、高原肺水肿和高原脑水肿, 是高原特发病之一, 在高原旅居者中(>2 500 m)具有高发生率, 不仅影响人们的工作能力和健康, 而且可能危及生命。尽管AHAD的相关研究已开展百余年, 其病理生理机制仍不明确, 但大量研究已证实AHAD存在易感性的差异。文章综述了迄今为止AHAD的遗传易感性研究进展, 以期为AHAD的流行病学研究提供有益的参考资料。     

温度对棉纤维糖代谢相关酶活性的影响

以棉纤维比强度高的科棉1号和中等强度的美棉33B 2个基因型棉花品种为材料,于2005年在江苏南京(长江流域下游棉区)和徐州(黄河流域黄淮棉区)设置不同播期(4月25日和5月25日)试验,研究了不同温度下棉纤维发育过程中蔗糖酶、蔗糖合成酶、磷酸蔗糖合成酶和β-1,3-葡聚糖酶等糖代谢相关酶活性的动态变化特征及其与纤维长度和比强度形成的关系.结果表明：棉纤维伸长发育期,蔗糖酶、β-1,3-葡聚糖酶活性较高;纤维加厚发育期,蔗糖合成酶和磷酸蔗糖合成酶活性上升速度快、活性高,蔗糖酶和β-1,3-葡聚糖酶活性下降速度快.纤维伸长期,蔗糖酶活性升高对纤维的伸长具有明显促进作用;纤维加厚发育期,提高蔗糖合成酶、磷酸蔗糖合成酶活性及加快蔗糖酶和β-1,3-葡聚糖酶活性下降速度有利于提高纤维比强度.科棉1号前期蔗糖酶、β-1,3-葡聚糖酶活性及中后期蔗糖合成酶、磷酸蔗糖合成酶活性均较美棉33B高.在本试验条件下,23.3 ℃是高强纤维形成的适宜温度,23.3 ℃～25.5 ℃是纤维长度形成的适宜温度.