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1.
The North-eastern region of India is rich treasure of various Citrus species. A vast reservoir of Citrus diversity exists in wild, semi wild form and is found scattered here and there without commercial cultivation and much care. The edaphic and climatic set up as well as the physiographic condition of the region makes it possible to grow a number of species, landraces and probable hybrids of Citrus without any care. But of now with the population increase, changing attitude of the farmers towards some newly introduced cash crops there is genetic erosion of the valuable resources and most of them are in verge of extinction. So, it is the high time for the scientific community to exploit all the rare and endangered resources of Citrus of north eastern region and for their conservation. In addition molecular and morphological characterization of the reported germplasm, evaluation and screening against biotic and abiotic stresses should also be needed to safeguard the existing population of Citrus and for future Citrus improvement programme.  相似文献   

2.
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.  相似文献   

3.
A collecting mission took place in June and July 1996 to collect legume species from south-west Turkey and western Anatolia. Sites were chosen to maximise the diversity of legumes collected and detailed passport data were recorded at each site. A total of 96 sites were visited, and 1307 accessions collected. In total 23 genera were collected, of which the most frequently seen were Trifolium, Medicago and Vicia. Sites were found to be almost exclusively calcareous with a pH range of 7 to 10, and varied from sea level to 1750m. Many of the Trifolium species are of economic importance for southern Australia and have been shown to display characters such as a high productivity (T. michelianum) and waterlogging tolerance (T. resupinatum and T. tomentosum). The Medicago species were found to prefer well-drained habitats in open areas. Many of these species can tolerate heavy grazing. The two main forage legume genera collected were Lathyrus and Vicia. Both of these occurred on the higher pH soils and were most frequently collected from the lower altitudes. Four species of grain legume were found, Cicer arietinum, Lens culinaris, Pisum sativum and Vicia faba. The material collected during this mission is important in the drive to preserve the legume genetic diversity of Turkey, the species' centre of diversity, for utilisation both within and outside of Turkey.  相似文献   

4.
Genetic Resources and Crop Evolution - Ecuador is one of the centers of diversity for wild and cultivated potatoes. Three micro-centers of diversity were previously identified based on germplasm...  相似文献   

5.
Summary Patterns of achene proteins of L. sativa cultivars are mutually compared and compared with L. saligna, L. serriola and L. virosa. L. virosa and L. saligna are easy to identify and are characterized by typical banding patterns. L. sativa and L. serriola share the same banding pattern. They differ clearly from L. saligna and L. virosa. L. sativa and L. serriola are closely related (in terms of similarity), they form a common genepool and L. serriola is involved in the domestication process of L. sativa. Cultivar identification was not possible with the SDS-PAGE method.  相似文献   

6.
Regional humus and surficial sediments were collected in the vicinity of a base metal smelter in Flin Hon. Results of total mercury (Hg) analyses indicate that enrichment in humus is related to emissions from the smelter stack up to a distance of 40 km. In the immediate vicinity of the point source, total Hg values reach as much as 250 times the regional background (400 ppb). This enrichment is not reflected in the underlying surficial sediments. The Hg distribution pattern is similar for other known metal pollutants emitted from the smelter.  相似文献   

7.
More species of snakes are becoming endangered yet information on their effective management is lacking. The present study assessed the general biology of the prairie garter snake, an endangered species in Ohio, USA, and the potential impact of mortality due to game management practices in a state wildlife area (automobile traffic and grass mowing operations). Alterations to the present management practices include alternatives such as rescheduling of mowing operations to coincide with the snake's periods of inactivity and using signs to caution motorists to avoid hitting snakes on the road. Future management of wildlife areas should not focus upon a single species or trophic level but rather consider both non-game and game species.  相似文献   

8.
RAPD variation in wild, weedy and cultivated azuki beans in Asia   总被引:12,自引:0,他引:12  
RAPD (Random Amplified Polymorphic DNA) variation was assessed in 42 accessions of azuki bean (Vigna angularis) including wild, weedy and cultivated races and in three accessions of two related species used as outgroups. A much lower level of genetic variation was observed in cultivated and weedy azuki beans compared to wild azuki bean. Wild azuki bean (V. angularis var. nipponensis) has relatively high genetic variation in subtropical highlands of Asia compared to the Far East. Although cultivated azuki bean has low RAPD variation, accessions from subtropical highlands and Southeast Asia showed different RAPD features compared to those of the Far East. It is hypothesized that the cultivated azuki bean has been derived from wild azuki bean in the Far East; the high variation in wild azuki bean has been created through its natural dissemination; and the relatively low variation in cultivated azuki bean has come about through human dissemination after genetic bottleneck reduced by domestication. In addition, high genetic diversity in wild azuki bean in subtropical highlands of Asia is regarded as an important genetic resource in azuki improvement.  相似文献   

9.
The potential gene flow between a crop and its wild relatives is largely determined by the overlaps in their ecological and geographical distributions. Ecogeographical databases are therefore indispensable tools for the sustainable management of genetic resources. In order to expand our knowledge of Sorghum bicolor distribution in Kenya, we conducted in situ collections of wild, weedy and cultivated sorghum. Qualitative and quantitative morphological traits were measured for each sampled wild sorghum plant. Farmers’ knowledge relating to the management of sorghum varieties and autecology of wild sorghum was also obtained. Cluster analysis supports the existence of several wild sorghum morphotypes that might correspond to at least three of the five ecotypes recognized in Africa. Intermediate forms between wild and cultivated sorghum belonging to the S. bicolor ssp. drummondii are frequently found in predominantly sorghum growing areas. Crop-wild gene flow in sorghum is likely to occur in many agroecosystems of Kenya.  相似文献   

10.
Mercury concentrations in basic ecosystem compartments of the Wabigoon-English River system are interrelated. Statistically significant correlations are evident between Hg levels in various biotic-young northern pike (Esox lucius), yearling yellow perch (Perca flavescens) and crayfish (Orconected virihs) and abiotic compartments (water, surface sediments). Highly significant positive correlations are found between methyl-mercury in water and Hg in biota. Highly significant positive correlations also exist between Hg levels in different organisms, despite differences in habitat, diet, uptake routes and proportion of bodyburden that is in the methyl form. A plausible basis for these relationships is the rapid equilibration between methyl and inorganic Hg in and between various abiotic components of the ecosystem and subsequent incorporation into food webs. As sediment-water partitioning for inorganic and methylmercury is also rapid it is likely that in lakes and slow moving river reaches, local environmental variables probably largely govern Hg body burdens in biota.  相似文献   

11.
A Lagragangian sampling strategy was chosen in order to evaluate the main sources of atrazine to the St. Lawrence River, Canada. Lagrangian sampling was carried out during six sampling trips, one at every hydrological season except winter from the period of the summer low flow of 1990 to the spring freshet of 1992. Loadings of atrazine are subject to annual variations induced by different climatic and hydrological conditions. Loadings of atrazine are also dependent on season. Results emphasize the persistence of atrazine as it was found in significant amounts at the end of the growing season and in the following spring. Variations in loadings of atrazine along the river as well as the lateral distribution of atrazine concentrations in a downstream direction suggest inputs within the province of Quebec. The Great Lakes and the international corridor of the St. Lawrence River contribute 68% of the loading exported to the estuary, while Quebec tributaries account for 8% of the inputs. The inportance of the unmeasured sources within the river itself (24%) stresses the need for further research on internal processes and contaminant transfer in the aquatic environment.  相似文献   

12.
Selenium has been recognized as essential for all mammals; therefore, its concentration level and speciation are of great concern. Plants are one of the main sources of selenium in the diet. Thus, inorganic selenium uptake and its transformation in different species were evaluated in Indian mustard (Brassica juncea), sunflower (Helianthus annus), and white lupine (Lupinus albus). More than 1.2 g x kg(-)(1) (dry matter) of Se was found in the aerial part of Indian mustard when growing on 1 mg x L(-)(1) of Se as Na(2)SeO(4), and approximately half this amount was determined in the leaves of the lupine, which is still quite high. Selenomethionine was the main selenium-containing amino acid identified in most of the extracts by HPLC-ICP-MS. The higher values were 6.8 and 14.5 mg x kg(-)(1) (expressed as Se in dry matter) in the leaves of lupine and sunflower, respectively. This is of great importance because some authors have considered the combination of this enriched material with non-enriched food as a source of selenium supplementation.  相似文献   

13.
14.
Temporal depositional rates are important in order to understand the production and occurrence of perchlorate (ClO4) as limited information exists regarding the impact of anthropogenic production or atmospheric pollution on ClO4 deposition. Perchlorate concentrations in discrete ice core samples from the Eclipse Icefield (Yukon Territory, Canada) and Upper Fremont Glacier (Wyoming, USA) were analyzed using ion chromatography tandem mass spectrometry to evaluate temporal changes in the deposition of ClO4 in North America. The ice core samples cover a time period from 1726 to 1993 and 1970 to 2002 for the Upper Fremont Glacier (UFG) and Eclipse ice cores, respectively. The average ClO4 concentration in the Eclipse ice core for the time period from 1970 to 1973 was 0.6 ± 0.3 ng L−1, with higher values of 2.3 ± 1.7 and 2.2 ± 2.0 ng L−1 for the periods 1982–1986 and 1999–2002, respectively. All pre-1980 ice core samples from the UFG had ClO4 concentrations <0.2 ng L−1, and the post-1980 samples ranged from <0.2 ng L−1 to a maximum of 2.6 ng L−1 for the year 1992. A significant positive correlation (R = 0.75, N = 15, p < 0.001) of ClO4 with SO42− was found for the annual UFG ice core layers and of ClO4 with SO42− and NO3 in sub-annual Eclipse ice samples (R > 0.3, N = 121, p < 0.002). The estimated yearly ClO4 depositional flux for the Eclipse ice core ranged from 0.6 (1970) to 4.7 μg m−2 year−1 (1982) and the UFG from <0.1 (pre-1980) to 1.4 μg m−2 year−1 (1992). There was no consistent seasonal variation in the ClO4 depositional flux for the Eclipse ice core, in contrast to a previous study on the Arctic region. The presence of ClO4 in these ice cores might correspond to an intermittent source such as volcanic eruptions and/or any anthropogenic forcing that may directly or indirectly aid in atmospheric ClO4 formation.  相似文献   

15.
Distribution, conservation status, trends, actions and ethnobotanical notes of segetal species growing in South Italy are presented and discussed. For the most threatened segetal species details and suggestions for their conservation are reported. Research work was made directly in the field for collecting samples and in the laboratory for checking several herbarium samples. To the best of our knowledges, a summary table of all species occurring in the field, of the investigated environments, and their ecological focus areas, is provided for the first time.  相似文献   

16.
The Moroccan phosphate industry releases large amounts of heavy metals in the Atlantic Ocean in the surroundings of two places: Safi and Jorf Lasfar. The major waste, called phosphogypsum and composed of calcium sulphate and other additional salts, is introduced into sea water in particulate form. After dissolution of the particles, heavy metal concentrations can be influenced near the release point. Two multi-element analytical techniques were used to measure 47 element concentrations in various materials involved in the study of the phosphate pollution: Inductively Coupled Plasma Mass Spectrometry (ICPMS) and instrumental neutron activation analysis (INAA). At first, phosphate and phosphogypsum were characterized in order to recognize the overall features of the heavy metal pollution source. From the yearly amount of phosphogypsum produced by the Moroccan industry and the element concentrations in phosphogypsum, it has been possible to estimate a yearly flux of heavy metals introduced in the Atlantic Ocean. Algae were used as bio-accumulator materials of heavy metals in the marine environment, in the region of Jorf Lasfar, in order to significantly reveal the signal of the heavy metal pollution. Ulva lactuca Linnaeus was selected to assess heavy metal pollution around the waste release point. Accumulation factors were determined for 47 elements in U. lactuca, by comparing mean concentrations obtained in algae collected in non-polluted sites (background sites) and an average sea water concentration given in the literature. The ratio between the concentration in U. lactuca, collected in a polluted site to the background concentration in U. lactuca, was determined, giving an estimate of the pollution factor for the same elements by the phosphate industry. The decrease of the pollution due to the dilution in the sea water was observed as far as 6 km southward of the release point. A specific variation was observed for lead and its isotopic composition, denoting that the phosphate industry is not the only pollution source in this region. Natural processes were likely involved to induce the lead concentrations variations along the littoral.  相似文献   

17.
Triple staining with the fluorochromes chromomycin A3, distamycin A and 4′-6-diamidino-2-phenylindole (CMA/DA/DAPI) was applied to somatic metaphases and interphase nuclei of 11 taxa of wild chili peppers (Capsicum), with 2n = 2x = 24 (C. annuum var. glabriusculum, C. cardenasii, C. chacoense, C. flexuosum, C. galapagoense, C. eximium, C. praetermissum and C. tovarii) and 2n = 2x = 26 (C. recurvatum, C. rhomboideum and C. villosum) to analyse heterochromatin type, amount and distribution in wild members of this genus. Heterochromatic banding patterns allowed the identification of all the taxa examined and contributed to their taxonomic grouping. GC-rich heterochromatin (CMA+/DAPI?) was typical in all taxa; only C. praetermissum possessed also AT-rich (CMA?/DAPI+) and mixed GC- and AT-rich (CMA+/DAPI+) bands. Heterochromatin amount (expressed as % of karyotype length) ranged between 1.72 (C. chacoense) and 16.82 (C. flexuosum) and was positively correlated with karyotype length in most of the taxa examined. Heterochromatin located mainly at terminal position of chromosomes but intercalary position prevailed in C. flexuosum. Nucleolus organizer regions (NOR)-associated GC-rich heterochromatin was exclusively terminal and included the distal macrosatellite and a small portion on the corresponding arm. In all the taxa analysed, an equilocal heterochromatin distribution in non-homologous chromosomes of karyotype was observed, suggesting concerted evolution of heterochromatin dispersion in Capsicum.  相似文献   

18.
During the summers of 1981-1984, 19,714 fish (23 species) were netted in 234 Nova Scotian lakes. Surface and mid-depth water samples were also analyzed for major ions, metals, and DOC. Lakewater pH varied from 4.4 to 7.7, including eight lakes which produced no fish in standard 23-hr net sets. Fish data were partitioned into 6 pH groupings for analysis. Stepwise multiple regressions of fish species vs. H+, S04,A1, Fe, and Mn showed little predictive power. Productive lakes ranged up to 530 μg L?1 Al, 1680 pg L?1 Fe, and 836 μg L?1 Mn. Apart from pH, fish distribution and abundance showed no significant relationships with water chemistry data. We note, however, that the more acidic lakes had fewer species of fish.  相似文献   

19.
4-epioxytetracycline and N-demethyloxytetracycline, as metabolites of oxytetracycline (OTC), 4-epitetracycline and N-demethyltetracycline, as metabolites of tetracycline (TC), and 4-epichlortetracycline, isochlortetracycline (ICTC), 4-epi-ICTC, and N-demethyl-ICTC, as metabolites of chlortetracycline (CTC), were detected in egg yolk and plasma obtained from feeding studies with either OTC, TC, or CTC. In egg white, only OTC, TC with its 4-epimer, and ICTC with its 4-epimer were detected in substantial concentrations. The ratios of epimerization and N-demethylation in the eggs did not change during the medication period. The samples were analyzed by an automated HPLC system (ASTED) with UV, fluorescence, or MS-MS detection.  相似文献   

20.
Limited information is available concerning the qualitative and quantitative composition of polyphenolic compounds, especially flavonoids, in almonds. We determined total phenols, flavonoids, and phenolic acids in California almond (Prunus dulcis) skins and kernels among the principal almond varieties (Butte, Carmel, Fritz, Mission, Monterey, Nonpareil, Padre, and Price) with high-performance liquid chromatography (HPLC)/electrochemical detection and UV detection. Liquid chromatography/tandem mass spectrometry under identical HPLC conditions was utilized to verify identities of the predominant flavonoids and phenolic acids. Total phenols ranged from 127 (Fritz) to 241 (Padre) mg gallic acid equivalents/100 g of fresh weight. The analyses were compiled to produce a data set of 18 flavonoids and three phenolic acids. The predominant flavonoids were isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-glucoside (in combination), catechin, kaempferol-3-O-rutinoside, epicatechin, quercetin-3-O-galactoside, and isorhamnetin-3-O-galactoside at 16.81, 1.93, 1.17, 0.85, 0.83, and 0.50 mg/100 g of fresh weight almonds, respectively. Using the existing approach of calculating only the aglycone form of flavonoids for use in the U.S. Department of Agriculture nutrient database, whole almonds would provide the most prevalent aglycones of isorhamnetin at 11.70 (3.32), kaempferol at 0.60 (0.17), catechin at 1.93 (0.55), quercetin at 0.72 (0.20), and epicatechin at 0.85 (0.24) mg/100 g of fresh weight (mg/oz serving), respectively. These data can lead to a better understanding of the mechanisms of action underlying the relationship between almond consumption and health-related outcomes and provide values for whole and blanched almonds suitable for inclusion in nutrient databases.  相似文献   

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