望天树人工林营养元素含量、积累与分配特征研究

对桂西南地区32年生望天树人工林乔木层的N、P、K、Ca、Mg等5种营养元素含量、积累及分配特征进行了研究.结果表明:望天树不同组分中各营养元素含量大致为树叶＞树皮＞树枝＞树根＞树干;树叶中以N含量最高,其他各器官中元素含量均以Ca含量最高,其次是N、P、Mg含量,K含量最小.乔木层5种营养元素累积总量达2 451.65 kg/hm2,各元素积累量表现为Ca＞N＞Mg＞P＞K,乔木层不同组分营养元素积累量表现为树干＞树皮＞树叶＞枝枝＞树根;5种营养元素年净累积量达76.61 kg/hm2.乔木层每积累1t干物质需要5种营养元素总量为7.12 kg,其中对Ca的需求量最大,其次是N、Mg,对P、K的需求最小.林下灌木层、草本层及凋落物层N、P、K元素平均含量稍高于乔木层,3种元素总积累量分别为7.69、13.58、64.89 kg/hm2.     

不同林龄云南松林营养元素积累与分配特征研究

【目的】对云南省玉溪市磨盘山云南松天然次生林5种营养元素(N、P、K、Ca、Mg)的含量、积累、分配及其随林龄变化的趋势进行研究,为云南松林养分利用及森林生态服务功能价值核算提供基础数据。【方法】选取15,30和45年生云南松天然次生林为研究对象,在各林龄林地中各设置3个20m×20m的标准样地,对样地内的乔木层按照叶、枝、干、根取样,灌木分叶、枝、根取样,草本分地上部分和地下部分取样,凋落物全部取样,同种植物的相同器官取混合样品,所有样品取回后在实验室进行生物量和营养元素含量的测定与分析。【结果】云南松不同器官营养元素含量大小次序为树叶树枝树根树干;各器官营养元素含量均以N最高,其次是K和Ca,Mg、P较低。15,30和45年生云南松天然次生林营养元素积累总量分别为192.00,930.95和2 357.36kg/hm2,其中乔木层营养元素积累量所占比例依次为70.70%,66.84%和98.82%,林下植被层所占比例依次为22.97%,7.53%,0.43%,地表现存凋落物所占比例依次为7.0%,26.98%和0.80%。乔木层、林下植被层和凋落物层均以N积累量最多,P最少。云南松N与P含量比随着林龄的增长呈下降趋势,15,30和45年生云南松天然次生林每积累1t干物质需要5种营养元素的总量分别为8.38,8.52和7.68kg,其中对N的利用效率最低,P最高。【结论】不同林龄云南松对营养元素的利用效率均较高,所以从营养元素利用效率来分析,云南松林不会因过度消耗土壤中的营养元素而导致土壤肥力降低,说明云南松有耐贫瘠、适应性强、适合荒山造林等特点。     

溶磷微生物菌剂对土壤营养元素及玉米生长的影响

为比较不同溶磷菌剂在田间应用效果,通过田间小区试验,研究3种菌剂草酸青霉I1(I1)、黑曲霉H1(H1)和巨大芽孢杆菌BM(BM)对土壤营养元素动态变化以及玉米产量的影响。结果表明:施用3种菌剂,土壤有效磷含量显著提高,在不同磷水平下,土壤有效磷含量比对照提高6.47%-37.13%。在P₂O₅92 kg·hm^-2水平下,在玉米生长前期,施用3种菌剂,土壤pH值显著降低,土壤交换性Ca、Mg和有效性Fe、Cu、Zn含量以及玉米叶片SOD、POD和CAT酶活性显著增加,而有效Mn的含量降低;总体上,各处理间提高土壤交换性钙、镁和有效锌的能力为H1>I1>BM,提高土壤有效铁能力为H1≥BM>I1,提高土壤有效铜能力为BM>H1>I1。不同磷水平下,施用3种菌剂后,玉米产量显著提高,在P₂O₅92 kg·hm^-2水平下,施用微生物菌剂玉米产量比CK增加8.2%-12.1%,总体上,增产效果为I1>H1>BM。     

Study on the variation of trace elements and oxidative stress in diaphragm of the diabetic rats

AIM:To investigate the relationship between trace elements and oxidative stress in diabetic diaphragm. METHODS: Contents of copper(Cu), manganese(Mn), zinc(Zn), iron(Fe),cadmium(Cd),chromium(Cr),cobalt(Co),molybdenum(Mo) and lithium(Li) in the alloxan-induced diabetic rat diaphragm muscles were measured by atomic absorption spectrophotometer, andtheir superoxide dismutase(SOD) activities and malondiadehyde(MDA) contents were detected. RESULTS: The contents of Cu, Zn, Cr and Li were lower and the Fe and Cd were higher in diabetic rat diaphragm muscles than that of the control group, but there were no significant differences in Mn, Co and Mo, between control and diabetic group. SOD activities decreased significantly and MDA contents increased significantly in diaphragm of diabetic rats as compared with the control group.In addition,in diabetic rats diaphragm, there was a positive correlation between Zn and SOD, and negative correlation between Zn and MDA, and Cd and SOD. CONCLUSION: Changes of the contents of Cu, Zn, Fe, Cd, Cr, Li and the increase of oxidative stress in diaphragm were found in the early diabetes, and Zn, Cd play an importment role in oxidative stress of diabetic diaphragm.     

Studies on the Molecular Structure of Vessels in Secondary Xylem of Stem from Three Carambola Varieties

[Objective] The aim of this study was to provide the theoretical basis for variety identification of carambola and pomiculture.[Method] The molecular structure of vessels in stem secondary xylem from three carambola varieties of Malaysia 8,Misi and Malaysia B17 were studied by cell image analysis system and microphotography.[Result] The molecular structure of vessels in stem secondary xylem from carambola was as follows:the first type had tails in two ends,the second type had tail in one end,and the third type had no tails in two ends.The average length of vessel elements was from 328.88 to 366.09 μm,while its average width was from 44.61 to 52.43 μm.Most of the end wall was simple perforation plates,while the alternate-opposite pitting was the major forms of pitting.[Conclusion] Most characteristics of vessel elements from carambola were evolutionary characters of vessel elements in the process of phylogeny,but there were more primitive characters,for example,both two ends of vessel had tails or just one end had tail,and end wall was inclined.The molecular structure of vessel from carambola was in accordance with its ecological adaptability,and the growth characteristics of different varieties were also in accordance with the difference of molecular structure of vessel.     

Effects of wind turbines and other physical elements on field utilization by pink-footed geese (Anser brachyrhynchus): A landscape perspective

The effects of wind turbines and other physical landscape elements on field utilization by wintering pink-footed geese (Anser brachyrhynchus) were studied in a Danish farmland landscape. Within the study area geese were feeding on pastures, which together with cereals were the main crop types. Apart from wind turbines a variety of potentially disturbing landscape elements was present, e.g., high-power lines, windbreaks, roads and settlements. Patterns of field use were assessed by measuring goose dropping densities along transects perpendicular to wind farms (with turbines in clusters and in lines) and other landscape elements. Local effects were expressed in terms of `avoidance distance', i.e., the distance from a given landscape element to the point at which 50% of maximal dropping density was reached. The spatial distribution of landscape elements within an eight km radius from the goose roost was determined from aerial photographs. The area occupied by various elements, together with the adjacent zones which were not available to geese due to their associated avoidance distances, were quantified using Geographic Information System (GIS).The avoidance distance of wind farms with turbines in lines and in clusters were ca 100 m and ca 200 m, respectively. Geese did not enter the area between turbines within the cluster. At the landscape level, the combined effect of physical elements other than wind turbines caused an effective loss of 68% of the total field area (40 km²). Wind turbines caused an additional loss of 4% of the field area. However, of the remaining area available to geese (13 km²), wind turbines caused a loss of 13% of the total area. The habitat loss per turbine was higher for the wind farm with turbines arranged in a large cluster than for wind farms with turbines in small clusters or lines. This difference was mainly due to the fact that wind farms in small clusters or with a linear layout were generally placed close to roads or other elements with existing associated avoidance zones, whereas the large cluster was placed in the open farmland area. The avoidance zones associated with physical elements in the landscape do not take into account possible synergistic effects and, hence, actual field areas affected are likely to be minimum estimates. Implications of these findings for planning of wind farms in areas of conservation interest to geese are discussed.     

使用JDBC实现自动气象站要素信息检索

介绍了使用JDBC实现自动气象站分中心站的气象要素信息检索，程序运用B／S体系结构，遵循MVC设计思想，采用Model2模式进行开发，为了提高程序的运行速度，在数据库中创建了存储过程。     

小鼠基因内含子中CpG岛和几个转录调控元件分析

内含子在基因转录调控中的作用已多次被实验报道,然而对其参与调控的普遍性还缺乏足够的理论支持。本研究利用计算分析方法,对小鼠基因内含子中的CpG岛（CpGisland）、TATA框（TATAbox）、CAAT框（CAATbox）以及GC框（GCbox）等元件的出现频率进行分析。结果发现,分别有56.01%、57.16%、65.88%和41.86%的第一内含子具有CpG岛、TATA框、CAAT框以及GC框,而它们在其它内含子中的平均出现频率则分别为14.07%、45.24%、49.91%和13.19%。即使考虑到不同位置的内含子,这些元件在第一内含子中的出现频率也显著高于它们在其它任何位置内含子中的出现频率。由于CpG岛、TATA框、CAAT框以及GC框均与基因的转录调控有关,据此推测小鼠第一内含子在基因转录调控过程中具有潜在的重要性。本研究结果为内含子参与转录调控提供了更多的理论依据。     

食用菌富集微量元素的研究与展望

本文综述了食用菌富集微量元素的特点，研究所用的食用菌菌种及所富集微量元素的种类，富集微量元素的食用菌生理功能、应用前景与存在问题。     

孔子史学思想研究

在孔子那里,“事”、“文”、“义”是史学三个必备的组成部分,“事”是史家对历史事件的选择和排比,“文”记载事件的文辞,“义”是贯穿始终的思想主线.文章从史家素养论和史学三要素这两个方面探讨研究孔子的史学思想.