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1.
Bacteriophages (phages) are the most abundant biological entities on the planet and are important as the greatest genomic reservoirs in both marine and terrestrial environments. In this study, we analysed T4-type phage communities in an upland black soil by monitoring g23 clones in DNA extracted from seasonal soil samples with no fertilizer, chemical fertilizers, chemical fertilizers plus manure, and natural restoration treatments. PCR products with degenerate primers MZIA1bis and MZIA6 were subjected to denaturing gradient gel electrophoresis. In total, 46 clones with different g23 sequences were obtained. Phylogenetic analyses indicated that T4-type phage communities in the upland black soil were distinctly different from those in marine environments and in an Antarctic lake, which strongly suggested that T4-type phage communities in soil differed from those in aquatic environments. Among 46 clones, 18 clones formed clusters with the clones from rice field soils, 14 clones formed three new clusters, and 13 clones were left as ungrouped, which indicated that T4-type phage communities in the upland black soil were relatively similar to those in rice field soils but that specific communities also inhabit in the upland black soil exclusively.  相似文献   

2.
In 2009 a greenhouse experiment was conducted to determine the effects of boron (B) and plant growth-promoting rhizobacteria (PGPR) treatments, applied either alone or in combination, on yield, plant growth, leaf total chlorophyll content, stomatal conductance, membrane leakage, and leaf relative water content of wheat (Triticum aestivum L. cv. Bezostiya) and barley (Hordeum vulgare L. cv. Tokak) plants. Results showed that alone or combined B (0, 1, 3, 6, 9 kg ha?1) and PGPR (Bacillus megaterium M3, Bacillus subtilis OSU142, Azospirillum brasilense Sp245, and Raoultella terrigena) treatments positively affected dry weight and physiological parameters searched in both species. Statistically significant differences were observed between bacterial inoculation and B fertilizer on root and shoot dry weight under non-cold-stress (NCS) and cold-stress (CS) conditions. Leaf total chlorophyll content (LTCC), stomatal conductance (SC), leaf relative water content (LRWC), and membrane leakage (ML) were negatively affected by CS conditions and decreased with reduced temperatures of media, but B and PGPR application alleviate the low-temperature deleterious effect in both species. The greatest SC and LRWC, and the lowest ML, were obtained by 6 kg B ha?1 combined with R. terrigena treatment. The greatest LTCC in both NCS and CS conditions was observed with B. megaterium M3 application alone.  相似文献   

3.
In order to evaluate the genetic diversity of cyanophage communities of rice fields, viral capsid assembly protein gene (g20) was amplified with primers CPS1 and CPS8. The DNA was extracted three times from viral concentrates obtained from floodwater samples collected in each of four different plots (no fertilizer; P and K chemical fertilizers; N, P, and K chemical fertilizers; and chemical fertilizers with compost). Denaturing gradient gel electrophoresis (DGGE) gave different g20 clones. The sequencing of DGGE bands revealed that the g20 genes of the floodwater were divergent and that the majority of clones formed several unique groups. However, they were more closely related to g20 sequences from freshwaters than to those from marine waters, suggesting that g20 genes in terrestrial aquatic environments are different from those in marine environments.  相似文献   

4.
In 1999, natural populations of Dactylis glomerata L., Festuca arundinacea Schreb., Phalaris tuberosa L. and the macrotherm species Brachypodium rupestre (Host) R. et S., were collected as seed in Southern Italy (Apulia, Basilicata and Campania regions) to evaluate the potential as forage of native germplasm under dry conditions, using available commercial cultivars as controls. The persistence of accessions, biometric, phenologic, productive and qualitative parameters of forage have been studied for a 3-year period (2000–2002) in a typical Mediterranean environment. D. glomerata is widely present in the studied area with two subspecies (subsp. glomerata L., subsp. hispanica (Roth) Nyman). The research pointed out significant differences in plant size, earliness and single plant dry matter (DM) production. All the natural ecotypes belonging to this species showed higher persistence than the control cultivars. Some natural ecotypes appeared to have potential for improving DM yield (subsp. glomerata ecotypes) and reducing neutral detergent fibre (NDF) content (subsp. hispanica ecotypes). Natural ecotypes belonging to F. arundinacea, P. tuberosa, and B. rupestre are sporadically present in the studied area. Among them, two ecotypes of P. tuberosa, showing higher winter growth and earliness compared to cv. ‘Holdfast’, seem to be interesting for a future breeding programme.  相似文献   

5.
To improve understanding of diversity of Lablab purpureus and establish relationships among 103 germplasm accessions collected from diverse geographic origins, amplified fragment length polymorphism markers were used. Four primer sets selected out of 16 produced 289 clear, repeatable polymorphisms. UPGMA analysis of similarity data clustered the accessions according to their subspecific taxonomic organization, i.e., subsp. purpureus and subsp. uncinatus, as well as to cultivated and wild forms. The well-represented landraces from Africa and Asia, belonging predominantly to subsp. purpureus, displayed moderate genetic diversity. Wild forms from Africa showed far greater levels of diversity that would justify taxonomic re-assessment of the wild subsp. uncinatus. The molecular analysis identified forms that were collected in the wild in India but were genetically placed intermediate between wild and cultivated forms. As these plant types did not exist among the African accessions, it is suggested that they might represent escapes from early attempts of domestication. These results support the suggested pathway of domestication and distribution of L. purpureus from Africa to Asia. Additional members to a previously published core collection of the species are proposed.  相似文献   

6.
Carbon isotope discrimination (Δ) has been proposed as physiological criterion to select C3 crops for yield and water use efficiency. The relationships between carbon isotope discrimination (Δ), water use efficiency for grain and biomass production (WUEG and WUEB, respectively) and plant and leaf traits were examined in 20 Iranian wheat genotypes including einkorn wheat (Triticum monococcum L. subsp. monococcum) accessions, durum wheat (T. turgidum L. subsp. durum (Desf.) Husn.) landraces and bread wheat (T. aestivum L. subsp. aestivum) landraces and improved cultivars, grown in pots under well-watered conditions. Carbon isotope discrimination was higher in diploid than in hexaploid and tetraploid wheats and was negatively associated with grain yield across species as well as within bread wheat. It was also positively correlated to stomatal frequency. The highest WUEG and grain yield were noted in bread wheat and the lowest in einkorn wheat. Einkorn and bread wheat had higher WUEB and biomass than durum wheat. WUEG and WUEB were significantly negatively associated to Δ across species as well as within bread and durum wheat. The variation for WUEG was mainly driven by the variation for harvest index across species and by the variation for Δ within species. The quantity of water extracted by the crop, that was closely correlated to root mass, poorly influenced WUEG. Environmental conditions and genetic variation for water use efficiency related traits appear to highly determine the relationships between WUEG and its different components (water consumed, transpiration efficiency and carbon partitioning).  相似文献   

7.
Bioavailability of Arsenic and Antimony in Terrestrial Ecosystems: A Review   总被引:1,自引:0,他引:1  
Arsenic (As) and antimony (Sb) are metalloids that belong to group 15 of the periodic table and exhibit toxic properties in the environment. They mostly occur naturally at low concentrations in soil, although these can be significantly elevated in both aquatic and terrestrial food chains as a result of dispersion from anthropogenic sources, e.g., mining activities. The bioavailability, i.e., the proportion of the contaminant in soil and dust that is available for uptake by plants and other living organisms, presents the greatest risk to terrestrial ecosystems. Various in vivo and in vitro methods have been used to measure As and Sb bioaccessibility in soil and dust. In vivo measurement of bioavailability can be time consuming, expensive, and unethical; thus, in vitro methods are commonly preferred. However, there is considerable uncertainty around the efficacy of in vitro tools used to measure the bioavailable fractions of As and Sb. The results of these methods are dependent on many variables, e.g., soil characteristics, contaminant sources, and chemical composition of in vitro methods. Therefore, substantial variations are observed between in vitro and in vivo results obtained from different test animals and endpoints. In this paper, we review the literature on As and Sb bioavailability in terrestrial ecosystems and current in vivo and in vitro techniques used for assessing bioavailability and bioaccessibility of metalloids. This would reveal research gaps and allow scientists and environmental policy makers to gain a deeper understanding of the potential risks associated with these metalloids in the environment.  相似文献   

8.
Cultivated lentil (Lens culinaris Medik. subsp. culinaris) has a relatively narrow genetic base and many commercial cultivars are susceptible to ascochyta blight caused by Ascochyta lentis Vassilievsky. A total of 375 accessions of six wild species of lentil received from ICARDA and 18 cultivated genotypes were screened for resistance to A. lentis under both field and greenhouse conditions in Saskatoon, Canada. A mixture of three monoconidial isolates of A. lentis was used as an inoculum and the level of infection rated using the Horsfall-Barratt scale (0–11). Accessions with resistance to A. lentis were observed in all wild species except for L. culinaris subsp. tomentosa (Ladiz.) Ferguson et al. showing no resistant accessions. Several consistently resistant accessions were found among entries of L. ervoides (Brign.) Grande and L. nigricans, (M. Bieb.) Godr., both of which belong to the secondary gene pool and a few in L. culinaris subsp. orientalis (Boiss.) Ponert and L. culinaris subsp. odemensis (Ladiz.) Ferguson et al. belonging to the primary gene pool. Some accessions of L. ervoides exhibited lower disease ratings and AUDPC values than the resistant control cv. ‘Indianhead.’ Thirteen accessions, previously reported as resistant to Syrian isolates of A. lentis were also resistant to the Canadian isolates; some also had resistance to anthracnose. The highest frequency of resistance was found in accessions of L. ervoides which originated from Syria and Turkey. These wild accessions represent a useful and untapped source for improving disease resistance in lentil.  相似文献   

9.
The extent to which invasive aquatic plants move via accidental inclusion in aquatic plant orders or sale of prohibited species is unknown. Forty orders were placed to 34 aquatic plant vendors across the US between May and September 2001 to determine the prevalence of movement into Minnesota via horticultural trade. Federal noxious weeds or Minnesota prohibited exotic species were acquired 92% of the time they were ordered and included Alternanthera sessilis, Butomus umbellata, Hydrocharis morsus-ranae, Potamogeton crispus, and Lythrum salicaria. Ninety three percent of orders received from aquatic plant vendors contained a plant or animal species not specifically requested; 10% of these purchases contained federal noxious weeds or Minnesota exotic species. Lemna minor was the most common incidental receipt found per taxa and per purchase, although Hydrilla verticillata, Lythrum salicaria, Salvinia molesta, and Potamogeton crispus (all prohibited taxa) were also found. Misidentified plants were found in 18% of the orders; unordered seeds in 43%. The sale and transport of prohibited aquatic plants likely presents the greatest risk associated with the aquatic plant trade. Other important factors include misidentification leading to the unintentional sale of invasive plants and the incidental inclusion of species during translocation.  相似文献   

10.
Fresh and dry plant weights were measured throughout a number of different CO2 enrichment experiments with six terrestrial plants and two aquatic species. Similar data were also extracted from the literature for 18 additional plants. In general, CO2 enrichment had little effect on plant percentage dry matter content, except under conditions conducive to starch accumulation in leaves, and then it caused an increase in percentage dry matter content.  相似文献   

11.
Pistacia is a common wild plant in the Southeast Anatolia part of Turkey. The experiment was planned to screen and select the most suitable arbuscular mycorrhizae (AM) for enhancing Pistacia species seedling growth by improving phosphorus (P) and zinc (Zn) uptake. This study was carried out under greenhouse condition at the Department of Soil Science, Çukurova University, Adana, Turkey. Two genotypes from each of P. vera (cvs ‘Siirt’ and ‘Kirmizi’), P. eurycarpa, P. atlantica, and P. terebinthus species were tested with ten different mycorrhizal species. Plants were grown in a growth medium with a mixture of sand, soil and compost with 6:3:1 ratio, respectively. Seedling plants were harvested after eight months and transplanted to pots. There were significant differences between Pistacia species in growth, nutrient uptake and the percentage of mycorrhizal infection. Also mycorrhizal species were different in terms of enhancing plant growth and nutrient uptake. The results were that Siirt, Genotype 08, 11, 13, and 14 gave a high response to the mycorrhizal inoculation and Glomus clarium gave the best improvements in growth and nutrition, resulting in greater plant biomass and Zn and P uptake. Following this, G. etunicatum, G. intraradices, G. caledonium, and G. mosseae species were effective species. In general, G. mosseae and G. fasciculatum mycorrhizae enhanced plant growth; G. clarium was the most efficient species in terms of P and Zn uptake.

It has been concluded that these mycorrhizae species significantly enhance the Pistacia plant growth and nutrient uptake. Also using AM fungi in the pistachio nursery should be taken into consideration for better seedling production. Further work needs to be done to determine how much inoculum is needed for sufficient inoculation and how the mycorrhizal seedlings can be adapted under field conditions especially under drought and high calcareous marginal soil conditions.  相似文献   

12.
Twenty nine germplasm lines of Chenopodium quinoa and two of Chenopodium berlandieri subsp. nuttalliae were evaluated for 12 morphological and 7 quality traits for two test seasons. The 19 traits were analyzed for cluster and principal component analysis. The first four PCs contributed 78.70 % of the variability among the germplasm lines. The first PC accounted for 39.5% of the variation and had inflorescence/plant, plant height and stem diameter as the traits with largest coefficients, all with positive sign. The characters with greatest positive weight on PC2 were days to maturity (0.309), inflorescence length (0.260) and branches/plant. All the germplasm lines were grouped into six clusters based on average linkage method. Cluster III had high values for seed yield and most of the quality traits but showed a small seed size. The dendrogram separated the two lines of C. berlandieri subsp. nuttalliae from the quinoa lines.  相似文献   

13.
In Central Vietnam, and more especially in Thua Thien Hue Province, aquatic plants are used empirically by some farmers as an external source of organic matter to improve fertility of sandy soils. The fertilization capacities of aquatic plant species [Najas indica (Willid.) Cham., Najas minor All., Vallisneria spiralis L. (Michx.) Torr., Hydrilla verticillata (L.f.) Royle, Potamogetum malaianus Miq., Myriophyllum spicatum L., Enteromorpha flexuosa (Wulfen) J. Agardh, Rhizoclonium kerneri Stockmayer, and Eichhornia crassipes (Mart) Solms] were assessed from a pot trial including soils amended with aquatic plants (5 g dry matter kg?1 soil) and soils supplied with increasing rates of urea nitrogen (N) fertilizers. Rice (Oryza sativa L.) at a vegetative stage was used as a convenient bio‐extractor. The fertilization capacity of aquatic plant amendments was calculated from aboveground biomass and from N accumulated in shoots as compared to treatments receiving only inorganic N fertilizers. Najas indica (Willid.) Cham. and Hydrilla verticillata (L.f.) Royle showed the greatest fertilization capacity, equivalent to 170–180 mg urea‐N kg?1 soil as estimated from biomass yield, whereas a lesser fertilization capacity, equivalent to less than 100 mg urea‐N kg?1 soil, was observed for Myriophyllum spicatum L., Enteromorpha flexuosa (Wulfen) J. Agardh, Rhizoclonium kerneri Stockmayer, and Eichhornia crassipes (Mart) Solms. This study provides quantitative data on the fertilization capacity of aquatic plants found in the coastal area of central Vietnam, which can improve this empirical practice and alleviate local agro‐environmental constraints related to the lack of organic matter in farming systems.  相似文献   

14.
Phylogenetic positions of characteristic bands of 16S rDNA that were obtained from the floodwater of a Japanese paddy field by denaturing gradient gel electrophoresis (DGGE) analysis in a previous work (Biol Fertil Soils 36:306–312, 2002) were determined to identify dominant bacterial members in the floodwater. Sequences of DGGE bands were affiliated with the CytophagaFlavobacteriumBacteroides group, β-Proteobacteria, and Actinobacteria and showed phylogenetically close relationships with species inhabiting other aquatic environments, although most of their closest relatives were uncultured bacterial clones.  相似文献   

15.
Present study reported the variation in electrophoretic seed subfraction (albumins, globulin A, globulin B, glutelins) patterns in some Lathyrus species collected from their natural habitats different localities in Turkey. Electrophoretic data were documented by using a gel documentation system (Bio-Rad, USA) and analysed by using Quantity 1-D analysis software and also the dendograms were formed with 4.0% tolerance in UPGAMA (Unweighed Pair-Group Arithmetic Mean). The differences among species were observed and all seven species were clearly identifiable from the protein patterns. The dendograms obtained from cluster analysis of seed storage proteins data showed examined species have displayed a number of distinct relationships. According to our results, it seems justified to recommend a wider use of electrophoretic analysis of seed storage proteins in taxonomic investigations of leguminous plants.  相似文献   

16.
RAPD markers were applied to subterranean clover aiming at: (i) assessing the genetic relationships among the subspecies subterraneum L., brachycalycinum Katzn. et Morley, yanninicum Katzn. et Morley, as their taxonomic status is still debated; (ii) verifying the adoption of RAPDs to supplement the common morphological markers used for cultivar identification and protection; (iii) assessing the possible genetic diversity in relation to the geographic origin. Eight primers were selected for genetic analysis of 18 genotypes: 10 subsp. yanninicum (five from Greece and five from Sardinia), six subsp. subterraneum (forming three pairs, each one difficult to distinguish by morphological markers), and two subsp. brachycalycinum. Cluster analysis, performed on the Jaccards coefficients of association computed across the eight primers, formed three groups of genotypes, corresponding to the three subspecies. The results supported at the DNA level previous inferences, made at cytological, karyological, and isoenzymatic levels, on the ongoing speciation process within the subterranean clover complex, although not warranting yet the full species rank to the three forms. The genotypes of subsp. yanninicum were genetically closer to those of subsp. subterraneum than either group was to the subsp. brachycalycinum genotypes. Within the subsp. yanninicum cluster, the Sardinian genotypes appeared fairly distinct from those from Greece, suggesting a possible, independent evolution going on in different centres of diversity of this subspecies. In two pairs of subsp. subterraneum genotypes, the members could be unequivocally distinguished, thus supporting the role of RAPD fingerprinting in cultivar identification. In the third pair, the two genotypes appeared to be the same, inadvertently duplicated within the germplasm collection.  相似文献   

17.
The chemical, physical and biological processes occurring in the rhizosphere can influence plant growth by modifying root associated microorganisms and nutrient cycles. Although rhizosphere has been widely investigated, little is known about the rhizosphere effect of pioneer plants in soils of periglacial environments. The knowledge of the processes controlling soil–plant relationships in these severe environments may help understanding the ecological evolution of newly deglaciated surfaces. We selected three plants [Helianthemum nummularium (L.) Mill. subsp. grandiflorum (Scop.), Dryas octopetala (L.), and Silene acaulis (L.) Jacq. subsp. cenisia (Vierh.) P. Fourn.] that sparsely occupy deglaciated areas of central Apennines (Italy), with the aim to assess changes between rhizosphere and bulk soil in terms of physical, chemical, and biological properties. The three plants considered showed to have different rhizosphere effect. Helianthemum induced a strong rhizosphere effect through a synergistic effect between root activity and a well adapted rhizosphere microbial community. Dryas did not foster a microbial community structure specifically designed for its rhizosphere, but consumes most of the energetic resources supplied by the plant to make nutrients available. Conversely to the other two species, Silene produced slight soil changes in the rhizosphere, where the microbial community had a structure, abundance and activity similar to those of the bulk soil. The ability to colonize harsh environments of Silene is probably linked to the shape and functions of its canopy rather than to a functional rhizosphere effect.This study showed that the rhizosphere effect differed by species also under high environmental pressure (periglacial conditions, poorly developed soil), and the activity of roots and associated microbial community is decisive in modifying the soil properties, so to create a suitable environment where plants are able to grow.  相似文献   

18.
Plant and animal species present on a coal fly ash slurry pond site and a dry deposit site were surveyed and sampled during a two-day period in October. Elemental analyses were determined for most of the species encountered. A total of 48 plant species were observed on the two sites, with 35 species on the wet site, and 20 on the dry site. Eighteen terrestrial and 7 aquatic animal species were found on the wet site, exclusive of vertebrates which were not studied with the exception of a carp (Cyprinus carpio). Eleven terrestrial invertebrates and one aquatic species were observed on the dry site. Neutron activation analysis was carried out for: Se, Hg, Cr, Ni, Zn, Co, Sb, Cd, and As. Using literature values for phytotoxicity, we conclude that, in general, plants did not accumulate toxic levels of metals. Only one plant (Impatiens biflora Willd.) showed a significant level of Cd. Of 20 plants analyzed on the wet site, 10 had excessive Se concentrations (>5 ppm); on the dry site 6 out of 18 had high Se values. In animals (Gryllus sp.; Melanoplus sp.; Trachelipus sp.; Lumbricus terrestris; Physa integra; Cyprinus carpio) the trace metal concentration was generally in between that of control animals and that of the fly ash itself. One exception included Zn, which, although the most variable element examined, was concentrated in all the terrestrial animals to levels higher than in fly ash. Crickets are the most consistent bioconcentrators with Cr, Se, and Zn at higher levels than for control animals. All animal species studied accumulated Se compared to controls.  相似文献   

19.
In the present study, we used 39 plant samples representing six Carthamus taxa collected from different regions of Turkey: 11 of C. dentatus, 5 of C. glaucus, 18 of C. lanatus, 3 of C. persicus, 1 of C. tenuis subsp. tenuis and 1 of C. tenuis subsp. gracillimus. On these samples, we screened nine ISSR markers for polymorphic products. We generated 151 polymorphic bands. In a dendrogram based on these ISSR bands, the first branch was C. tenuis subsp. gracillimus, then C. persicus formed the second group. The rest of the taxa were grouped in two clusters: the first included C. lanatus, C. tenuis subsp. tenuis and C. glaucus, and the second included C. dentatus. Within the first cluster, C. tenuis subsp. tenuis and C. glaucus grouped together and then united to C. lanatus. Representatives of the same taxa consistently clustered together. Also within species, the groupings were generally concordant with their geographical distributions.  相似文献   

20.
Two germplasm collections of Lablab purpureus L. Sweet totalling 249 accessions were grown in the field in Australia and Ethiopia and characterised using a common set of morphological and agronomic (M-A) attributes. Data from each site were analysed separately using multi-variate analysis and a classification constructed for each collection. There was considerable diversity within both collections, especially that maintained in Ethiopia. Time to flowering, seed weight, and plant height were the most important attributes in determining group allocation in both classifications. Both collections had a high proportion of L. purpureus subsp. purpureus, especially accessions similar to the Australian cultivars Highworth and Rongai. They also had good representation of the less common L. purpureus subsp. uncinatus Verdc. less common landraces and wild collections from either Africa or India. When combined, the two classifications provided an overview of diversity and highlighted the similarities and dissimilarities between the two collections. The vast range in plant types supported the view that lablab has the capacity to be a multi-purpose legume for both commercial and smallholder agriculture. Some important and less common germplasm identified were Ethiopian domesticated subsp. uncinatus, Ethiopian subsp. purpureus landraces collected from regional markets, semi-domesticated and wild accessions from southern Africa, and wild accessions from India. Using this overview, a core collection of germplasm was selected, which provides researchers with a sound basis for future plant breeding and agronomic studies with this important tropical legume.  相似文献   

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