卤代烷烃脱卤酶基因在拟南芥中反式失活系统的建立

以细菌Xanthobacterautotrophicus卤代烷烃脱卤酶基因为遗传负选择标记 ,建立了该基因在拟南芥中反式失活的实验系统 .在卤代烷烃脱卤酶转基因拟南芥中 ,有 1株表现为转基因失活 ,离体核run off转录实验表明为基因转录后沉默 (这里特指沉默位点 ) .用这一转基因沉默植株与同源转基因高效表达植株 (这里特指同源转基因位点 )杂交 ,结果 96 %的F1代植株表现为同源转基因反式失活 .将F1代植株自交 ,使部分沉默位点与反式失活的同源转基因位点分离 ,结果 2 0 0株子代中有 42株表现DhlA活性 ,15 8株无DhlA活性 ,即dhlA沉默植株与表达植株之比为 3 .76∶1,表明沉默位点是以孟德尔显性因子方式使同源转基因位点反式失活的 .

森林采伐对森林景观的长期影响模拟

应用空间直观景观模型(LANDIS),模拟了小兴安岭友好林业局在有无采伐方案下400年内森林景观的动态变化,并利用统计软件APACK计算代表性树种的分布面积、年龄级和反映物种分布格局的聚集度指数。结果表明:与无采伐相反,采伐下的火干扰模式为高频率小面积低强度火烧;采伐对各种群的分布面积影响不大,但显著改变了种群的年龄结构,主要表现为降低了过熟林的分布面积,而增加了其他年龄级森林的分布面积;采伐降低了各树种的聚集度,导致森林景观一定程度上的破碎化。

沙地云杉林植物区系特征的研究

根据野外调查,分析了沙地云杉林的植物区系成分,进行了种子植物的统计并得出结论:在沙地云杉林中,共有161种植物,分别属于49科,123属。其中1种蕨类植物,2种裸子植物,158种种子植物。共有10种地理成分分布类型,其中以达乌里-蒙古成分占优势,内蒙古自治区的特有成分只有沙地云杉一种。根据优势成分分析,发现在乔木层中只有沙地云杉和白桦达到存在度的4~5级,灌木层中只有黑果木旬子木达到5级。根据相似系数比较发现:沙地云杉林有56.8%的科、47.4%的属、47.4%的种与大针茅草原相同;有60.8%的科、22.3%的属、7.2%的种与长白山的典型暗针叶林相同,因此沙地云杉林仍然属于暗针叶林范畴。

施用化肥对下辽河平原稻田土壤线虫群落产生的影响

通过田间小区试验,研究了施用化肥对下辽河平原稻田土壤线虫群落组成产生的影响。结果表明,共获得15科、19属,其中绕线属、小杆属、垫刃属为优势属。线虫总数、食细菌线虫、植物寄生线虫和杂食-捕食线虫数量在不同处理之间存在极显著差别(p<0.01),三个施肥处理中的线虫总数显著高于无肥处理(对照)。在水稻收获后土壤线虫数量变化对不同种类肥料具有不同的响应。

试论大渤海地区污染之区域整治

分析了大渤海地区污染现状和主要污染问题．应用系统动力学仿真模型，预测了地区经济发展对未来环境影响．以生态学和区域科学的基本观点，提出了该地区污染之区域整治的基本对策．１）治理目标的整体性．经济发展要充分考虑地区自然资源长期供给能力，污染治理要与经济支持能力相适应．２）因地制宜分区治理．根据不同地区的功能，实行分类管理和治理．３）建立资源、经济、环境协调发展体系，调整工业结构，将资源利用贯穿于开发、利用、加工及产品转化的全过程，对严重缺水、污染比较严重的三大城市群严格控制大耗水、耗能工业的发展，将新建的耗水、耗能工业尽可能安排在滨海地区．４）对主要污染流域、海域和城市群实行重点区域治理．

乙草胺胁迫对土壤真菌拮抗功能和假单胞菌以及芽胞杆菌群落结构的影响

真菌拮抗功能是自然健康土壤对病原真菌所具有的免疫能力,这种能力与土壤中许多可分泌拮抗物质的细菌有关,而假单胞菌和芽胞杆菌是目前研究最多的具拮抗功能的种群。乙草胺是北方使用量最大的除草剂,目前它的施用对土壤真菌拮抗能力的影响还未见报道。本文通过室内模拟培养,考察不同浓度乙草胺(0、50、150、250mg·kg-1土)对土壤真菌拮抗能力的影响,并运用PCR-DGGE(变性梯度凝胶电泳)方法研究真菌拮抗功能逐渐下降的土壤样品中假单胞菌和芽胞杆菌群落结构变化情况。结果表明,在实验室微宇宙条件下,乙草胺的施用会降低土壤真菌拮抗能力,在处理第12d时可以得到土壤真菌拮抗功能差异显著的土壤样品。土壤芽胞杆菌多样性随乙草胺浓度的升高而下降,而假单胞菌多样性变化不大。乙草胺胁迫下芽胞杆菌和假单胞菌群落结构都发生明显改变,尤其是芽胞杆菌(处理土壤样品与对照的群落结构相似性为0.60),且施加浓度越高,群落结构组成偏离自然土壤越远。真菌拮抗能力的降低与假单胞菌和芽胞杆菌多样性和结构的改变相关。

中国东北8种藓类植物染色体数目

本文对中国东北 8种藓类植物染色体数目进行了报道。其中赤茎藓Pleuroziumschreberi (Brid .)Mitt.,n =5 ;塔藓Hylocomiumsplendens (Hedw .)B .S .G .,n =11;粗肋羽藓Thuidiumrecognitum (Hedw .)Lindb .,n =11;绿羽藓T .assimile (Mitt.)Jaeg .,n =11;四齿藓TetraphispellucidaHedw .,n =8;侧枝匐灯藓Plagiomniummaximoviczii (Lindb .)Kop .,n =6 ;尖叶匐灯藓P .cuspidatum (Hedw .)Kop .,n =12 ;具缘提灯藓Mniummarginatum (With .)Beauv .,n =6。绿羽藓的染色体数目为首次报道 ,赤茎藓 ,塔藓 ,粗肋羽藓和四齿藓为国内首次报道

西藏自治区土壤风力侵蚀与沙地变化研究

根据遥感调查的土壤风力侵蚀数据和用主成份分析法得出的土壤风力侵蚀动力指数,对西藏自治区土壤风蚀进行宏观分析。根据中国资源环境数据库中近10年来遥感调查的土地利用时空变化数据,对西藏沙地变化进行空间分析,发现沙地总体上没有明显扩展,处于缩小的过程。沙地主要变化为人工林地,表明了人为因素对沙地的减少做出重要贡献。将地貌数据与沙地的空间分布数据进行叠加,发现西藏的沙地主要分为3种类型:湖积平原型、洪积平原型和河流谷地型。每种类型有着较为独特的沙地成因、分布格局和变化方式,成为西藏风力侵蚀的特点。70年代以来的沙漠化气候因子值偏小,表明了气候因素所导致的土地沙化趋势在减弱。

Synthesis and near-infrared luminescent properties of some ruthenium complexes

A series of seven ruthenium complexes with different ligands were synthesized and their optical, electrochemical and photoluminescent properties were characterized. Electroluminescent properties of these complexes were further evaluated using a light-emitting electrochemical cell with a configuration of indium tin oxide (ITO)/complex (100 nm)/Au (100 nm).

Hole-transporting polymers containing carbazol-3,9-diyl and 1,4-phenylene fragments in the main chain

New carbazole-based polymers, which contain various content of electro-active fragments in the main chain connected via alkylene spacers, have been synthesized by Ni(0)-catalyzed Yamamoto-type aryl-aryl coupling reactions. These compounds represent amorphous materials of high thermal stability with glass-transition temperatures of 139-151 degrees C and thermal decomposition starting at temperatures above 400 degrees C. UV-vis absorption and photoluminescence emission spectra of the materials confirmed that the conjugated segments in the macromolecules are rather short.

Cross-linkable aromatic amines as materials for insoluble hole-transporting layers in light-emitting devices

A series of cross-linkable aromatic amines has been synthesized by the multi-step synthetic rout. Full characterization of their structure by H-1 NMR-, IR- and mass spectrometry is presented. The synthesized materials were examined by various techniques including differential scanning calorimetry, thermogravimetry, UV and electron photoemission spectrometry.

Controlled synthesis of organic-inorganic hybrid nanofibers by a wet-chemical route

Organic-inorganic hybrid nanofibers are successfully synthesized by incorporating 3,3 ',5,5 '-tetramethylbenzidine (TMB) and H2PtCl6 at room temperature. The morphology and size can be simply controlled by tuning the molar ratio and initial concentration of reactants. A possible formation mechanism was suggested on the basis of the experimental results. The optical properties were investigated and the as-obtained product displays a strong fluorescence emission at room temperature that may be promising for applications in the fabrication of photoelectric materials. (C) 2008 Elsevier B.V. All rights reserved.

Infrared spectroscopic study on thermal behavior of Langmuir-Blodgett films of octadecyl ammonium octadecanoate and octadecylammonium octadecanoate-d(35)

Langmuir-Blodgett (LB) films of octadecylammonium octadecanoate (C(18)H(37)j7NH(3)(+)C(17)H(35)COO(-),ODASA) and octadecylammonium octadecanoate-d(35) (C18H37+NH3+C17D35COO-, ODASA-d(53)) were prepared and their thermal behaviors were investigated by variable-temperature Fourier transform infrared transmission spectroscopy. It was found that the two hydrocarbon chains of ODASA molecule in LB films are highly ordered while that protonated (H) chain in ODASA-d(35) is partially disordered with some gauche conformers introduced at room temperature.

Effects of thermal annealing on polymer photovoltaic cells with buffer layers and in situ formation of interfacial layer for enhancing power conversion efficiency

We have investigated the effects of thermal annealing before and after cathode deposition on poly(3-hexylthiophene)(P3HT)/[6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend photovoltaic cells with different cathode buffer layers. The introduction of cathode buffer layer such as lithium fluoride (LiF) and calcium oxide (CaO) in pre-annealing cells can increase the open-circuit voltage (V-oc) and the power conversion efficiency (PCE). Post thermal annealing after cathode deposition further enhanced the PCE of the cells with LiF/Al cathode.