丛枝菌根真菌对柑橘组培苗生长和抗氧化酶的影响

在温室条件下以枳〔Poncirus trifoliata(L.)Raf.〕组培苗为试材,研究了接种Glomus versiforme和G.mosseae对其生长、碳水化合物和抗氧化酶的影响.结果表明,接种G.versiforme的组培苗和接种G.mosseae的组培苗分别在第二级侧根和第一级侧根中观察到最高的菌根侵染率、泡囊数、丛枝数和侵入点.两种丛枝菌根真菌都显著提高了茎粗、叶面积、叶片数、根系体积、地上部干重、地下部干重、叶绿素和类胡萝卜素含量.两种丛枝菌根真菌显著促进了叶片和根系可溶性糖以及总的非结构碳水化合物含量.丛枝菌根真菌也提高了叶片和根系中SOD、POD和CAT活性,但显著抑制了叶片和根系中可溶性蛋白含量.G.versiforme对柑橘组培苗生长和碳水化合物的促进效果较好;G.mosseae对组培苗抗氧化酶的促进效果较好.表4参26     

A Numerical Study for Turbulent Flow and Thermal Influence over Inhomogenous Canopy of Roughness Elements

A large-eddy simulation with transitional structure function(TSF) subgrid model we previously proposed was performed to investigate the turbulent flow with thermal influence over an inhomogeneous canopy, which was represented as alternative large and small roughness elements. The aerodynamic and thermodynamic effects of the presence of a layer of large roughness elements were modelled by adding a drag term to the three-dimensional Navier–Stokes equations and a heat source/sink term to the scalar equation, respectively. The layer of small roughness elements was simply treated using the method as described in paper (Moeng 1984, J. Atmos Sci. 41, 2052–2062) for homogeneous rough surface. The horizontally averaged statistics such as mean vertical profiles of wind velocity, air temperature, et al., are in reasonable agreement with Gao et al.(1989, Boundary layer meteorol. 47, 349–377) field observation (homogeneous canopy). Not surprisingly, the calculated instantaneous velocity and temperature fields show that the roughness elements considerably changed the turbulent structure within the canopy. The adjustment of the mean vertical profiles of velocity and temperature was studied, which was found qualitatively comparable with Belcher et al. (2003, J Fluid Mech. 488, 369–398)’s theoretical results. The urban heat island(UHI) was investigated imposing heat source in the region of large roughness elements. An elevated inversion layer, a phenomenon often observed in the urban area (Sang et al., J Wind Eng. Ind. Aesodyn. 87, 243–258)’s was successfully simulated above the canopy. The cool island(CI) was also investigated imposing heat sink to simply model the evaporation of plant canopy. An inversion layer was found very stable and robust within the canopy.     

五氯酚生物降解机理与外生菌根真菌对五氯酚可降解性

五氯酚是氯酚族中最具毒性和最难降解的有机污染物。不同种类的微生物由于其降解污染物的生化机制不同,使得五氯酚的降解途径多样化。文章通过综述好氧与厌氧微生物降解五氯酚的降解菌和降解途径,认为五氯酚首先通过脱氯转化为低氯代化合物后再开环,因此脱氯就成为五氯酚降解的关键步骤。参与脱氯的关键酶系主要包括过氧化物酶和酚氧化酶。外生菌根真菌可降解多种难降解有机污染物,并具有生成过氧化物酶和酚氧化酶的机制,因此外生菌根真菌具有降解五氯酚的潜力与优势。这些信息将为进一步开展五氯酚生物降解机理研究,应用微生物—植物复合系统修复污染土壤提供基础。     

Assessing water quality in a tropical lake using biomarkers in zebrafish embryos: developmental toxicity and stress protein responses

In order to achieve a more substantial appraisal of lake water quality, the assessment must not be based only on chemical measurements and analyses of the water itself, but even more so on the impact of existing conditions on aquatic biota. This is possible with the use of biotests or biomarkers, e.g. investigations of the developmental parameters (96-h embryotoxicity evaluate) or of the induction of heat shock proteins (proteotoxicity evaluate). To evaluate the suitability of these tests for environmental screening, fertilized zebrafish eggs were exposed to water samples collected from five sites of varying levels of stress from Laguna Lake, Philippines. Reconstituted water was used as laboratory control while water samples from a highly polluted freshwater source was used as positive control. Developmental parameters were noted and described within 48 and 96 h of exposure. Dilution experiments of the positive control were also done to further assess and compare toxicity potentials of Laguna Lake waters with those originating from a polluted freshwater. After the 96-h exposure, the levels of stress proteins (hsp 70) were determined in embryos from all exposure groups. Results showed 100% mortality in embryos exposed to undiluted positive control (PC) within only 12 h. Increasing dilution levels, however, resulted in lower mortality and lower abnormality rates. No detectable developmental differences were noted among embryos exposed to either the laboratory control or Laguna Lake waters at the end of 96 h, regardless of the source. Very high survival rates and high hatching success rates were observed in embryos exposed to lake waters as well as laboratory control, and the data did not differ significantly among the groups. Likewise, no significant malformations were noted among all developing embryos throughout the exposure period. However, the levels of heat shock proteins in the two sites located closest to Manila, the Philippine capital (Northern West Bay and Central West Bay), showed a pronounced elevation relative to the control, indicating that these stress proteins protect the embryos from the detrimental effects of pollutants in the water. Based on the 96-h early life stage (ELS) test, the water quality of the lake is good for fishery propagation despite the current levels of pollutants in the water. This finding is in accordance with the Class C status (i.e. suitable for fish growth and propagation) as given to the lake by the local environmental agency. On the other hand, data on proteotoxicity showed that the fish are under stress, presumably deriving from pollutants. This calls for a continuous monitoring and improvement of the lake water. The present study indicates that the two biomarker methods are very easy to use, practical, rapid, and sensitive for assessing water quality in a tropical lake and recommends for their incorporation into the future monitoring program of Laguna Lake.     

新型长时热流测量装置的研制及应用

目的设计一种新型热流测量装置,使传感器满足长时间热流测量的需求,且传感器外表面可以适量打磨,与飞行器的气动外型面完好随型。方法采用铜和钢作为备选材料,施加相同的表面热流边界,对比敏感端内外壁温差情况。优化热流辨识传感器传热路径、敏感端厚度,通过有限元模型分析打磨对热流辨识结果的影响。基于优化结果,研制出热流测量装置,并通过地面试验验证该装置的有效性。结果从热响应获取时间延迟角度来看,Cu比钢具有较大的优势。综合考虑敏感端外表面需要与飞行器外表面随型打磨,选用5 mm的厚度具有一定的安全可靠性。敏感端的适度打磨基本不影响温度测量结果。辨识获得的热流数据与实际控制热流吻合较好,最大偏差约15%。结论成功研制了热流测量装置,并通过地面热试验证明了热流测量的有效性。     

中国城市人为热通量估计及时空分布

基于中国统计年鉴中1985~2018年全国能源消耗和人口数据,估计中国城市人为热排放通量及其时间变化趋势.利用人口空间分布和污染物排放清单数据,探讨人为热排放的空间分布特征.依据能源类型,人为热分为工业、交通运输、建筑和新陈代谢4类排放.结果表明,我国人为热排放多年来持续增长,2000年增长加速,2012~2016年增速有所放缓.2016年我国平均人为热排放通量达到0.442W/m²,工业、建筑、交通、新陈代谢排放的全国平均人为热排放通量分别为0.311,0.072,0.038和0.020W/m².人为热排放的高值主要分布在京津冀、长江三角洲、珠江三角洲重点城市群区域以及其他一些规模较大的区域重点城市.4类人为热排放均呈现东部多、西部少的特点.工业排放人为热分布与区域经济发展水平和城市化程度有关.交通运输排放的人为热主要集中在交通枢纽城市.与已有的人为热排放清单相比,本研究估计的人为热排放通量在规模较大的城市具有更大的数值,更能体现人类活动对人为热排放的贡献.     

黄曲霉A5p1对偶氮染料的降解特性和降解途径

以黄曲霉菌株A5p1为生物材料,研究其脱色染料的广谱性,并选择偶氮染料直接蓝71（DB71）为模型底物,探讨脱色特性及降解产物.该菌株对15种染料的脱色测试结果表明,染料浓度为100mg/L时脱色效率为61.7%~100%.该菌对偶氮染料DB71具有生物吸附和生物降解的双重作用,在pH值7.0,温度30℃,染料浓度300mg/L,蔗糖为碳源时对DB71 脱色率为100%.酶分析显示葡萄糖氧化酶和锰过氧化物酶参与染料的降解.FTIR、GC-MS和LC-MS分析确定代谢终产物为萘胺、叠氮萘、2-羟基-6-草酰-苯甲酸和1-萘酚.     

石墨相氮化碳光催化灭活水中多重耐药菌研究

研究了光辐照和基于石墨相氮化碳（g-C₃N₄）光催化对二级出水中1株四环素和氨苄西林抗性多重耐药菌E.coli CGMCC 1.1595的灭活效果.结果表明,汞灯辐照功率（100/300/500W）和辐照强度越高,其灭活效率相对越高,在500W汞灯60min辐照条件下,紫外长波（UVA）-可见光（300~579nm）对该多重耐药菌的灭活率为0.41log;基于g-C₃N₄的光催化对其灭活率为1.31log.相比未加g-C₃N₄催化剂的光辐照灭菌,在UVA-可见光条件下g-C₃N₄对其灭活率的贡献为61%~69%;在可见光条件下g-C₃N₄对其灭活率的贡献达到60%~79%.在UVA-可见光g-C₃N₄光催化灭活E.coli CGMCC 1.1595反应体系中,活性氧自由基和电子空穴的活跃程度为：·OH > ·O₂^- > H₂O₂ > h⁺ > ¹O₂,·OH为该光催化体系的主要活性物质,其次是·O₂^-和H₂O₂.     

陆面模式Noah-MP模拟地表热通量的物理过程不确定性分析

陆面过程中的热量交换对于确定生态系统中的水文循环、边界层发展、天气和气候至关重要,然而目前陆面模式Noah-MP对地表热通量模拟的偏差在-180~180 W·m^-2之间,为明确模拟不确定性来源,本研究基于FLUXNET全球热通量观测数据,在5种气候类型、9类下垫面系统定量评估了Noah-MP感热和潜热通量模拟的不确定性.结果表明：Noah-MP在不同类型下对感热和潜热通量模拟的平均误差主要分布在-80~10 W·m^-2和-30~10 W·m^-2之间,模型在气候类型为热带和干旱气候以及下垫面类型为草地、针叶林、落叶阔叶林的模拟误差最大.研究发现植被过程是热通量模拟不确定性的主要来源,其次是水文过程和土壤过程;其中动态植被模型（DVEG）是植被过程模拟的主导因子,其次是湍流输送过程（SFC）、冠层气孔阻抗（CRS）和冠层辐射传输（RAD）.     

基于格点数据的中国1961—2016年≥5 ℃、≥10 ℃有效积温时空演变

为了解气候变暖对农作物种植区域的影响,基于5日滑动平均、累积距平、MK检验、多元回归插值方法,选用格点数据对中国农业热量资源进行分析。结果表明：（1）≥5 ℃、≥10 ℃有效积温整体呈上升趋势,且≥5 ℃整体升幅更为显著,两者升幅均表现为南方地区最大,北方次之,青藏高原最小,秦巴山区积温呈现下降现象。（2）在空间分布上,≥5 ℃、≥10 ℃有效积温整体表现出自南向北随纬度更替变化的地带性分布和自东向西随海拔变化的阶梯状分布,东、中部地区受纬度影响明显,西部地区受海拔影响强于纬度。适宜喜凉作物种植的区域远大于喜温作物的适宜种植面积。（3）≥5 ℃、≥10 ℃有效积温均在1997年发生突变,突变后≥5 ℃、≥10 ℃各积温带界线呈现向北、向高海拔移动的趋势,积温整体升高。南方地区≥5 ℃、≥10 ℃积温增幅整体大于北方,青藏高原及高山山区增幅最小,秦岭地区积温增幅为负。（4）≥5 ℃、≥10 ℃有效积温初始日（结束日）整体呈提前（推迟）现象,且多数格点提前（推迟）日数在0~10 d以内,持续时间在突变后整体延长。青藏高原≥5 ℃、≥10 ℃积温初始日（结束日）提前（推迟）天数最大。