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21.
ROH Mark S DE BENEDETTI Laura JOUNG Young Hee LEE Nam Sook 《应用与环境生物学报》2007,13(2):145-151
Germplasm collection is important to preserve and maximize genetic diversity for germplasm conservation. Tsuga dumosa ( D. Don) Eichler in Engler & Prantl. and T. chinensis var. forrestii (Downie) Silba germplasm was collected from three localities in China: Mt. Yulong, Wenfeng Temple and Mt. Dishiergu, Yunnan Province. Accessions were identified based on morphological characters and RAPD markers. The shapes of the apices and margins of needles were examined, and the length and width of needles, cones and seeds from accessions of mature plants were used to compare the morphological differences and to identify the germplasm. Molecular markers generated by randomly amplified polymorphic DNA (RAPD) were also used to characterize the taxa. Although the clustering based on RAPD markers was inconsistent with the morphological characters of the needles, based on the overall morphological characters and on RAPD markers, the accessions from Mt. Yulong and Wenfeng Temple were identified as T. chinertsis var. forrestii, and those from Mt. Dishiergu identified as T. dumosa. Taxonomic identification of the accessions was made based on morphology and by RAPD markers concurred. The results indicate that the shapes of the apices and margins of needles particularly from young plants could not be used as a possible key to identify T. dumosa and T. chinertsis var. forrestii. Fig 6, Tab 3, Ref24 相似文献
22.
不同植被对工业污染区盐渍土的改良效果 总被引:1,自引:0,他引:1
以包头市西郊工业污染区盐渍化弃耕地为对象,研究了不同植被对土壤水盐动态和体积质量的影响。研究表明,造林后使林地内草本植物得到较快恢复,且归还土壤的枯落物比木本植物多,改良盐渍土壤和促进脱盐的作用较好;随植被盖度增加,盐渍土土壤含盐量和体积质量降低,盐渍土性状逐步改善。因此,在实施以耐盐树种造林为先导的工业污染区盐渍土恢复植被工程时,应适当降低造林密度,以利于林地内草本植物的恢复和建立林草复合植被,提高工业污染区盐渍土的生物治理效果。 相似文献
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24.
Jebali J Banni M de Almeida EA Boussetta H 《Environmental monitoring and assessment》2007,124(1-3):195-200
Levels of the oxidative DNA damage 7, 8-dihydro-8-oxo-2′-deoxyguanosine (8-oxodG) and catalase (CAT) activity were measured
in the digestive gland and gills of clams Ruditapes decussatus, related to the presence of pollutants along Tunisian marine environment. Increased levels of CAT were observed in tissues
of clams from all the sites studied, compared to control values, and elevated 8-oxodG levels were observed at specific sites.
Results obtained in this work indicate that the measurement of 8-oxodG levels and CAT activity in tissues of R. decussatus is promising in pollution monitoring studies of the Tunisian marine environment. 相似文献
25.
BEN H. J. DE JONG MICHAEL A. CAIRNS PATRICIA K. HAGGERTY NEPTALÍ RAMÍREZ-MARCIAL SUSANA OCHOA-GAONA JORGE MENDOZA-VEGA GONZÁLEZ-ESPINOSA IGNACIO MARCH-MIFSUT 《Environmental management》1999,23(3):373-385
6 tons C were released to the atmosphere during the period of time covered by our study, equal to approximately 34% of the
1975 vegetation C pool. The Chiapas highlands, while comprising just 0.3% of Mexico's surface area, contributed 3% of the
net national C emissions. 相似文献
26.
The application of positive matrix factorization in the analysis, characterisation and detection of contaminated soils 总被引:4,自引:0,他引:4
Multivariate factor analytical techniques are widely used for the approximation, in terms of a linear combination of factors, of multivariate experimental data. The chemical composition of soil samples are multivariate in nature and provide datasets suitable for the application of these statistical techniques. Recent developments of multivariate factor analytical techniques have led to the approach of Positive Matrix Factorization (PMF), a weighted least squares fit of a data matrix in which the weights are determined depending on the error estimates of each individual data value. This approach relies on more physically significant assumptions than methods like Principal Components Analysis which is frequently used in the analysis of soil datasets. In this paper we apply PMF to characterise the pollutant source in a set of geographically referenced soil samples taken within a 200 m radius of a site characterised by a high concentration of heavy metals. Each sample has been analysed for major and minor elements (using wavelength-dispersive X-ray fluorescence spectrometry), carbon, hydrogen and nitrogen (using a CHN elemental analyzer) and mercury (using cold-vapour atomic absorption spectrometry). Analysis of the soils using PMF resulted in a successful partitioning of variances into sources related to background soil geochemistry, organic influences and those associated with the contamination. Combining these results with a geostatistical approach successfully demarcated the main source of the combined organic and heavy metal contamination. 相似文献
27.
This paper examines the changing trends in world tin demand for the period 1962–1985. In the early 1970s tin production peaked, and has since declined. The reasons for the decline are examined in terms of changes in product composition of income (i.e. mix of goods and services), changes in material composition of products, decline in gross domestic investment and the rising price of tin. 相似文献
28.
In 1982, for the first time since OPEC was founded in 1961, its production was surpassed by the non-OPEC countries in the world excluding the centrally planned economies. In that year, for the world as a whole, OPEC provided 35% of the oil consumed. The decline was brought about by a decrease in consumption and by a marked increase in production from non-OPEC sources. It is expected that non-OPEC producers will have the capacity to meet more than half of the world's oil requirements until the early 1990s, at which time OPEC producers will again assume the role of providing over 50% of the world's oil. 相似文献
29.
分析了不同污染负荷下膜生物反应器的运行效率,并运用酶活表征污泥活性,用磷脂脂肪酸(PLFAs)分析微生物种群结构及其分布特征.结果表明,膜生物反应器对COD,TP,TN,NH4+-N 保持着高而稳定的去除率,不同有机负荷下去除率差异不大(P>0.05);磷酸酶活性在低污染负荷下最高,脱氢酶、β-糖苷酶在中低污染负荷时的活性比高污染负荷时高,脲酶及蛋白酶活性随负荷增加而升高;活性污泥PLFAs 组成以单不饱和脂肪酸、饱和脂肪酸和支链脂肪酸为主,而多不饱和脂肪酸与环丙烷脂肪酸含量较少,特征脂肪酸的比值表明在反应器中好氧细菌占绝对优势;微生物的群落结构分析显示,活性污泥中好氧原核微生物为优势类群,其次是革兰氏阳性细菌及其他厌氧细菌,而真核微生物所占比例最低. 相似文献
30.
John Munthe Eva Brorström-Lundén Magnus Rahmberg Leo Posthuma Rolf Altenburger Werner Brack Dirk Bunke Guy Engelen Bernd Manfred Gawlik Jos van Gils David López Herráez Tomas Rydberg Jaroslav Slobodnik Annemarie van Wezel 《Environmental Sciences Europe》2017,29(1):13