塔克拉玛干沙漠腹地胡杨林土壤细菌多样性分析

【目的】对塔克拉玛干沙漠腹地胡杨林土壤细菌多样性进行初步探索,为下一步从中筛选可用于生物饲料或生物肥料的微生物奠定基础。【方法】采用可培养方法,进行细菌的分离纯化。对各菌株进行革兰氏染色及淀粉酶、酯酶、纤维素酶和NaCl耐受浓度的测定,并提取各菌株基因组DNA,进行16SrRNA基因扩增、测序及系统进化树的绘制,分析其多样性。【结果】共分离得到27株菌,其中放线菌门(Actinobacteria)16株,变形菌门(Proteobacteria)4株,厚壁菌门(Firmicutes)6株,拟杆菌门(Bacteroidetes)1株。革兰氏染色结果表明,5株菌为革兰氏阴性,其余为革兰氏阳性;酶活测定结果表明,15株菌具有淀粉酶活性,9株菌具有酯酶活性,9株菌具有纤维素酶活性;NaCl耐受浓度测定结果显示,NaCl浓度为2%时所有菌株均能生长,5%时能生长的有22株,15%时能生长的有1株。【结论】塔克拉玛干沙漠腹地胡杨林土壤中存在较丰富的细菌类群,且具有一定的酶学活性和NaCl耐受性,具有进一步研究开发的价值。     

Use of digital webcam images to track spring green-up in a deciduous broadleaf forest

Understanding relationships between canopy structure and the seasonal dynamics of photosynthetic uptake of CO₂ by forest canopies requires improved knowledge of canopy phenology at eddy covariance flux tower sites. We investigated whether digital webcam images could be used to monitor the trajectory of spring green-up in a deciduous northern hardwood forest. A standard, commercially available webcam was mounted at the top of the eddy covariance tower at the Bartlett AmeriFlux site. Images were collected each day around midday. Red, green, and blue color channel brightness data for a 640 × 100-pixel region-of-interest were extracted from each image. We evaluated the green-up signal extracted from webcam images against changes in the fraction of incident photosynthetically active radiation that is absorbed by the canopy (f _APAR), a broadband normalized difference vegetation index (NDVI), and the light-saturated rate of canopy photosynthesis (A _max), inferred from eddy flux measurements. The relative brightness of the green channel (green %) was relatively stable through the winter months. A steady rising trend in green % began around day 120 and continued through day 160, at which point a stable plateau was reached. The relative brightness of the blue channel (blue %) also responded to spring green-up, although there was more day-to-day variation in the signal because blue % was more sensitive to changes in the quality (spectral distribution) of incident radiation. Seasonal changes in blue % were most similar to those in f _APAR and broadband NDVI, whereas changes in green % proceeded more slowly, and were drawn out over a longer period of time. Changes in A _max lagged green-up by at least a week. We conclude that webcams offer an inexpensive means by which phenological changes in the canopy state can be quantified. A network of cameras could offer a novel opportunity to implement a regional or national phenology monitoring program.     

四川小寨子沟自然保护区苔藓植物资源调查分析

在调查和分类的基础上,发现小寨子沟自然保护区共有苔藓植物153种,分别属于92属,72科.通过对苔藓植物的优势类群、科属的区系成分、垂直分布以及群落类型的分析,结果表明:小寨子沟自然保护区苔藓植物(1)物种多样性丰富.(2)优势类群明显.(3)垂直分布显著.(4)温带分布为主.     

马边大风顶国家级自然保护区种子植物区系研究

马边大风顶国家级自然保护区位于四川省马边县境内。在野外考察及查阅文献的基础上,对保护区内种子植物区系进行了研究。结果显示：保护区内有种子植物120科,446属,1240种,其中裸子植物5科,11属,27种;被子植物115科,435属,1213种。保护区区系成分较复杂,古老区系成分和滇藏高原成分较多。种子植物科的分布区类型有11个,具有较强的热带性质,泛热带（热带广布,Pantropic）型34科,占总科数的40．96％,属的分布区类型有15个,以温带区系成分为主,共264属,占总数属的64．71％。相似性系数计算结果显示,其与美姑大风顶自然保护区种子植物区系亲缘关系十分密切,区系组成相当一致,应该属于同一古老区系演化而成。     

广西龙虎山自然保护区种子植物区系分析

本文对广西龙虎山自然保护区种子植物区系进行分析。龙虎山有野生种子植物851种,隶属136科536属。龙虎山区系世界分布科占25.0%,热带分布科占59.6%,温带分布科占15.4%。热带分布占本区系总属数的80.6%;温带分布占本区系总属数的18.4%,中国特有分布属占1.0%。龙虎山种子植物区系具有明显的热带性质和岩溶区系性质,特有现象较丰富。     

Evaluation of CuO oxidation parameters for determining the source and stage of lignin degradation in soil

The composition of phenols and other aromatic compounds in organic and mineral soil horizons and their respective source vegetation from different climatic zones of the Canadian Prairies were analyzed using CuO oxidation and gas chromatography-mass spectrometry (GC-MS) to investigate the stage of lignin degradation. Parameters based on the CuO oxidation products were calculated for the soils and corresponding vegetation to determine the lignin sources and to monitor the lignin degradation. In addition to the widely used lignin monomer parameters, parameters resulting from lignin-derived phenolic dimers are used for the first time to assess lignin degradation in soils. The composition of lignin-derived phenols (S/V, C/V) in soil closely matches the composition observed in their respective source plants (grass, Aspen, Pine) reflecting the preservation of characteristic lignin patterns in soils. Degradation parameters based on lignin phenols and benzenes derived from tannins or other phenolic biomolecules indicate a progressive degradation from the vegetation to the soil horizons. In addition to commonly used lignin monomer indicators, parameters based on the lignin dimers are applied. Lignin degradation is found to be lowest in the Pine forest, intermediate in the grassland soils and highest in the Aspen-grassland transition soil. Degradation parameters based on non-lignin aromatic derivatives (3,5-dihydroxybenzoic acid, benzenepolycarboxylic acids) demonstrate a similar trend. The lignin from samples in the cooler climate (Black Chernozems) is observed to be more oxidized than in the soils from the warmer climate (Brown Chernozems) suggesting that abiotic processes may be in involved in the alteration of lignin and other phenolic biomolecules in soils. The results indicate that the comparative analysis of CuO oxidation products of soils and source vegetation is a valuable tool to assess the sources and degradation of lignin in soils.     

太白山自然保护区羚牛分布的初步调查

羚牛（Ｂｕｄｏｒｃａｓｔａｘｉｃｏｌｏｒ）,为国家一级保护野生动物。羚牛秦岭亚种为我国特产亚种,分布于甘肃、陕西两省。在陕西省内分布于秦岭中、西段。羚牛在太白山自然保护区的分布情况,迄今仅见一些零星报道［１,２］。１９９６年６～９月,作者在太白山自然...     

The Community Dynamics of the Forest Secondary Succession in Heishiding Natural Reserve of Guangdong Province

Studying on the community structure, species composition and species diversities of the secondary succession of lower subtropical forest in Heishiding Natural Reserve, Guangdong Province, the following results were obtained. In 2 ~4 years of restored stage the seedlings of pioneer species, heliophytes and mesophytes occur simultaneously. In 10 years of restored stage pioneer species are superior as heliophytes maintain stable and mesophytes are being decreased. In the stage of mixed forest pioneer species are on the decreasing and heliopytes are on the increasing trend. In the stage of evergreen broad-leaved forest dominated by heliophytes pioneer species are being declined, heliophytes are dominant and mesophytes are being increased. In the stage of evergTeen broad-leaved forest dominated by mesophytes heliophytes are being declined and mesophytes are superior. The vertical structure, horizontal structure, the structure of species composition determine stability of communities in secondary succession process. The vertical structure of community is building up in the stage of restoration. The community is composed of the stands under the third class. The forest canopy is not stratified. The individual density is stable. From restored stage to mixed forest the vertical structure of community is diversified. There are the third and forth class stands in community. The tree layer is divided into three sub-layers. The individual density declines rapidly because of self-thinning. In the mixed forest the vertical stmcture is relatively stable. The abundance of the fifth class stands and area of breast height reach the first peak in the succession serial. The individual density increases rapidly. In stage of evergreen broad-leaved forest dominated by heliophytes, the vertical structure changes largely. The abundance of the fifth class and area of breast height decline rapidly, but the individual density changes slowly. In the stage of evergreen broad-leaved forest dominated by mesophytes, the vertical structure of community is stable and the composition of every stand class becomes more stable. The area of breast height is the biggest in the succession serial. When succession develops, the coverage of communities increases gradually but the turnover rate of species declines. The species composition tends to be stabilized. The diversity of species and community evenness increase gradually thus, the ecological dominance declines gradually.     

甘肃兴隆山自然保护区马麝夏季栖息地特征及生境选择格局

2006—2008年夏季(7—8月),对甘肃兴隆山自然保护区马麝(Moschus Sifanicus)的栖息地特征和夏季生境选择格局进行了研究。用Mann-Whitney U检验和χ2检验比较了马麝夏季利用生境样地(n=71)和对照性非利用样地(n=264)间的海拔等17个生态变量的差异,结果表明,兴隆山马麝夏季利用生境的郁闭度[(53.87±3.09)%]和乔木均高[(7.57±0.83)m]均显著大于非利用样地[郁闭度:(49.07±1.66)%,乔木均高:(6.33±0.32)m],喜食植物多度[(12.97±1.80)]株也显著大于非利用样地[(9.61±0.67)株]。此外,与非利用样地相比,兴隆山马麝夏季倾向于选择位于中坡位较陡(67.61%)、距离水源较近(<1000m,77.46%)、隐蔽度(88.73%)和避风性均较好(90%)及距人为干扰较远(>1000m,76.06%)的生境;主成分分析结果表明,前4个因子的累积贡献率达72.45%,由乔木胸径和乔木郁闭度变量组成的乔木因子是决定马麝夏季生境选择的首要因素,此外,海拔因子,由地表植被盖度和食物多度组成的食物因子,由灌木盖度、乔木密度和灌木...