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1.
A fertile amphidiploid × Brassicoraphanus (RRCC, 2n = 36) between Raphanus sativus cv. HQ-04 (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) was synthesized and successive selections for seed fertility were made from F4 to F10. F10 plants exhibited good fertility with 14.9 seeds per siliqua and 32.3 g seeds per plant. Cytological observation revealed
that frequent secondary pairing occurred among 3 chromosome pairs in pollen mother cells of plants (F4) with lower fertility, but not of plants with high fertility (F10). GISH analysis indicated that these F10 plants included the expected 18 chromosomes from R. sativus and B. alboglabra, respectively, but they lost approximately 27.6% R. sativus and 35.6% B. alboglabra AFLP (amplified fragment length polymorphism) bands. The crossability of the Raphanobrassica with R. sativus and 5 Brassica species (13 cultivars) were investigated. Seeds or F1 seedlings were easy to be produced from crosses × Brassicoraphanus × R. sativus, and B. napus, B. juncea and B. carinata × Brassicoraphanus. Fewer seeds or seedlings were obtained from crosses × Brassicoraphanus × B. napus, B. juncea and B. carinata. However, few seeds were harvested in the reciprocals of × Brassicoraphanus with B. rapa and B. oleracea. The possible cause of fertility improvements and the potential of the present × Brassicoraphanus for breeding were discussed. 相似文献
2.
Tânia Luz Palma Mbagag Neba Donaldben Maria Clara Costa Jorge Dias Carlier 《Water, air, and soil pollution》2018,229(6):200
Paracetamol, the most widely and globally used analgesic and antipyretic, is easily accumulated in aquatic environments. In the present study, the biodegradation of paracetamol in different media (one for general growth, one specific for sulfate reducing bacteria, a mineral salts medium and municipal wastewater) inoculated with two types of sludge (from anaerobic lagoon and from oxidation ditch) under different oxygenic conditions (anoxic; moderate oxygenation in open flasks and high oxygenation by aeration) was investigated. In addition, bacteria with relative abundances increasing simultaneously with paracetamol degradation, when this drug was the only carbon source, thus with a putative role in its degradation, were identified using 16S rRNA gene sequences. The results show that aerobic microorganisms had a major role in the degradation of paracetamol, with 50 mg/L totally removed from municipal wastewater after 2 days incubation with aeration, and that the metabolites 4-aminophenol and hydroquinone plus one compound not identified in this work were produced in the process. The identification of bacteria with a role in the degradation of paracetamol revealed a strain from genus Pseudomonas with the highest final relative abundance of 21.2%, confirming previous works reporting strains of this genus as paracetamol decomposers. Besides, genera Flavobacterium, Dokdonella and Methylophilus were also in evidence, with initial relative abundances of 1.66%, 1.48 and 0.00% (not detected) in the inoculum and 6.91%, 3.80 and 3.83% after incubation, respectively. Therefore, a putative role of these genera in paracetamol biodegradation is suggested for the first time. 相似文献
3.
Houyang Kang Meiyu Zhong Quan Xie Haiqin Zhang Xing Fan Lina Sha Lili Xu Yonghong Zhou 《Genetic Resources and Crop Evolution》2012,59(3):445-453
Trigeneric hybrids may help establish evolutionary relationships among different genomes present in the same cellular-genetic
background, and also offers the possibility to transfer different alien characters into cultivated wheat. In this study, a
new trigeneric hybrid involving species from the Triticum, Psathyrostachys and Secale was synthesized by crossing wheat-P. huashanica amphiploid (PHW-SA) with wheat-S. cereale amphiploid (Zhongsi 828). The crossability of F1 hybrid was high with 35.13%, and the fertility was 41.95%. The morphological characteristics of F1 plants resembled the parent Zhongsi 828. The trigeneric hybrids pollen mother cells (PMCs) regularly revealed averagely 19.88
univalents, 9.63 ring bivalents, 3.97 rod bivalents, 0.60 trivalents and 0.03 tetravalents per cell. Multivalents consisted
of trivalents and tetravalents can be observed in 52.7% of cells. A variation of abnormal lagging chromosome, micronuclei
and chromosome bridge were formed at anaphase I and telophase II. The mean chromosomes number of F2 progenies was 2n = 46.13, and the distribution range was 42–53. GISH results revealed that most F2 plants had 6–12 S. cereale chromosomes, and only 0–2 P. huashanica chromosomes were detected. The results indicated that S. cereale chromosomes can be preferentially transmitted in the F2 progenies of trigeneric hybrid than P. huashanica chromosomes. A survey of disease resistances revealed that the stripe rust resistance from the PHW-SA were completely expressed
in the F1 and some F2 plants. The trigeneric hybrid could be a useful bridge for the transference of P. huashanica and S. cereale chromatins to common wheat. 相似文献
4.
The present study was conducted to isolate and characterize rhizobial strains from root nodules of cultivated legumes, i.e. chickpea, mungbean, pea and siratro. Preliminary characterization of these isolates was done on the basis of plant infectivity test, acetylene reduction assay, C-source utilization, phosphate solubilization, phytohormones and polysaccharide production. The plant infectivity test and acetylene reduction assay showed effective root nodule formation by all the isolates on their respective hosts, except for chickpea isolate Ca-18 that failed to infect its original host. All strains showed homology to a typical Rhizobium strain on the basis of growth pattern, C-source utilization and polysaccharide production. The strain Ca-18 was characterized by its phosphate solubilization and indole acetic acid (IAA) production. The genetic relationship of the six rhizobial strains was carried out by random amplified polymorphic DNA (RAPD) including a reference strain of Bradyrhizobium japonicum TAL-102. Analysis conducted with 60 primers discriminated between the strains of Rhizobium and Bradyrhizobium in two different clusters. One of the primers, OPB-5, yielded a unique RAPD pattern for the six strains and well discriminated the non-nodulating chickpea isolate Ca-18 from all the other nodulating rhizobial strains. Isolate Ca-18 showed the least homology of 15% and 18% with Rhizobium and Bradyrhizobium, respectively, and was probably not a (Brady)rhizobium strain. Partial 16S rRNA gene sequence analysis for MN-S, TAL-102 and Ca-18 strains showed 97% homology between MN-S and TAL-102 strains, supporting the view that they were strains of B. japonicum species. The non-infective isolate Ca-18 was 67% different from the other two strains and probably was an Agrobacterium strain. 相似文献
5.
Valéria Marino Rodrigues Sala Elke Jurandy Bran Nogueira Cardoso Fabiana Fantinatti Garboggini Neusa de Lima Nogueira Adriana Parada Dias da Silveira 《Biology and Fertility of Soils》2008,44(8):1107-1112
This study reports for the first time the presence of diazotrophic bacteria belonging to the genera Achromobacter and Zoogloea associated with wheat plants. These bacterial strains were identified by the analysis of 16S rDNA sequences. The bacterium
IAC-AT-8 was identified as Azospirillum brasiliense, whereas isolates IAC-HT-11 and IAC-HT-12 were identified as Achromobacter insolitus and Zoogloea ramigera, respectively. A greenhouse experiment involving a non-sterilized soil was carried out with the aim to study the endophytic
feature of these strains. After 40 days from inoculation, all the strains were in the inner of roots, but they were not detected
in soil. In order to assess the location inside wheat plants, an experiment was conducted under axenic conditions. Fifteen
days after inoculation, preparations of inoculated plants were observed by the scanning electron microscope, using the cryofracture
technique, and by the transmission electron microscope. It was observed that all isolates were present on the external part
of the roots and in the inner part at the elongation region, in cortex cells, but not in the endodermis or in the vascular
bundle region. No colonizing bacterial cells were observed in wheat leaves. 相似文献
6.
This study aimed to investigate the effect of inoculation with plant growth-promoting Rhizobium and Pseudomonas species on NaCl-affected maize. Two cultivars of maize (cv. Agaiti 2002 and cv. Av 4001) selected on the basis of their yield
potential were grown in pots outdoors under natural conditions during July. Microorganisms were applied at seedling stage
and salt stress was induced 21 days after sowing and maintained up to 50% flowering after 120 days of stress. The salt treatment
caused a detrimental effect on growth and development of plants. Co-inoculation resulted in some positive adaptative responses
of maize plants under salinity. The salt tolerance from inoculation was generally mediated by decreases in electrolyte leakage
and in osmotic potential, an increase in osmoregulant (proline) production, maintenance of relative water content of leaves,
and selective uptake of K ions. Generally, the microbial strain acted synergistically. However, under unstressed conditions,
Rhizobium was more effective than Pseudomonas but under salt stress the favorable effect was observed even if some exceptions were also observed. The maize cv. Agaiti
2002 appeared to be more responsive to inoculation and was relatively less tolerant to salt compared to that of cv. Av 4001. 相似文献
7.
Xiao-ming Wu Bi-yun Chen Guangyuan Lu Han-zhong Wang Kun Xu Gao Guizhan Yunchun Song 《Genetic Resources and Crop Evolution》2009,56(7):1011-1022
Mustard (Brassica
juncea) is an important crop in both ancient and modern world. It has a broad resource of genetic diversity that is used primarily
as oilseed but as vegetables, condiment and medicines also. Its superior tolerance to adverse environments, e.g., drought,
high temperature and low fertility suggests its better adaptability in future possible harsh environments. Chinese vegetable
mustard displays a wide spectrum of morphotypes. A collection of 95 accessions of B. juncea representing oil and vegetable mustards from China, France, India, Pakistan, and Japan were assessed to determine diversity
at the molecular level using sequence-related amplified polymorphism (SRAP). Eight SRAP primer combinations identified a total
of 326 scorable fragments of which 161 were polymorphic (49.39%). The percentage of polymorphism for each primer combination
varied from 21.88 to 66.67%. Both Shannon-Weaver and Simpson genetic diversity index indicated that the level of genetic diversity
within vegetable mustard is much higher than within oil mustard, and also winter oil mustards are genetically more diverse
than spring oil mustards. Based on the Cluster and Principal Coordinates analysis, which were conducted on the similarity
matrix of SRAP marker data, vegetable, spring oil and winter oil mustard were clearly divided into three distinct groups and
among these three groups, spring and winter oil mustard are geneticlly closer than vegetable mustard. This suggests that bilateral
gene exchange between oil and vegetable gene pools in the breeding program will effectively elevate the genetic potential
in developing higher yields, more disease resistance, better quality and better adapted lines. 相似文献
8.
Bio-fertilizer application has been proposed as a strategy for enhancing soil fertility, regulating soil microflora composition, and improving crop yields, and it has been widely applied in the agricultural yields. However, the application of bio-fertilizer in grassland has been poorly studied. We conducted in situ and pot experiments to investigate the practical effects of different fertilization regimes on Leymus chinensis growth, with a focus on the potential microecological mechanisms underlying the responses of soil microbial composition. L. chinensis biomass was significantly (P?<?0.05) increased by treatment with 6000 kg ha?1 of Trichoderma bio-fertilizer compared with other treatments. We found a positive (R2 =?0.6274, P <?0.001) correlation between bacterial alpha diversity and L. chinensis biomass. Hierarchical cluster analysis and nonmetric multidimensional scaling (NMDS) revealed that soil bacterial and fungal community compositions were all separated according to the fertilization regime used. The relative abundance of the most beneficial genera in bio-fertilizer (BOF) (6000 kg ha?1Trichoderma bio-fertilizer) was significantly higher than in organic fertilizer (OF) (6000 kg ha?1 organic fertilizer) or in CK (non-amend fertilizer), there the potential pathogenic genera were reduced. There were significant negative (P?<?0.05) correlations between L. chinensis biomass and the relative abundance of several potential pathogenic genera. However, the relative abundance of most beneficial genera were significantly (P?<?0.05) positively correlated with L. chinensis biomass. Soil properties had different effects on these beneficial and on these pathogenic genera, further influencing L. chinensis biomass. 相似文献
9.
Silke Neu Ingo Müller Carsten Brackhage Rafał Gałązka Grzegorz Siebielec Markus Puschenreiter E. Gert Dudel 《Journal of Soils and Sediments》2018,18(6):2259-2270
Purpose
The in situ stabilization of multielement-contaminated agricultural soils has limited effectiveness when using common single amendments. This study examined the use of drinking water treatment residues (WTR), based on (hydr)oxides of Fe, Al, or Mn, as a cost-effective solution to optimize the immobilization of metals (Cd, Pb, Zn) and As.Materials and methods
Trace elements (TE) bioavailability was assessed under semi-controlled conditions in a pot study cultivating winter wheat (Triticum aestivum L. cv. Tiger) until maturity. An Fe-based WTR and a Mn-based WTR, applied at rates of 0.5 and 1% (m/m), were related to effects of lime marl (LM) application. Additionally, a bioassay with earthworms (Dendrobaena veneta) was conducted. Both bioassays were compared with measurements of NH4NO3-soluble, diffusive gradients in thin film (DGT)-available and soil solution TE concentrations, representing well-established surrogates for mimicking the bioavailable element fractions in soil.Results and discussion
The application of the Fe-based WTR reduced As accumulation in vegetative wheat tissues (by up to 75%) and earthworms (by up to 41%), which corresponded with the findings from soil chemical analyses and improved plant growth and earthworm body weight. However, As concentrations in cereal grains were not affected, Cd or Pb accumulation by wheat was not mitigated, and Zn uptake was enhanced. By contrast, the Mn-based WTR effected the greatest reduction in Pb uptake, and lowered Cd transfer to wheat grain (by up to 25%). Neither the NH4NO3-soluble nor DGT-available concentrations matched with Cd and Zn accumulation in plants or earthworms, indicating interferences due to competition for binding sites according to the biotic ligand model.Conclusions
The results obtained in this study suggest that a bioassay with key species prior to field application should be mandatory when designing in situ stabilization options. The application of WTR to an agricultural soil strongly affected TE bioavailability to plants and earthworms. Low application rates tended to improve biomass production of biota. Higher application rates involved risks (e.g., P fixation, TE inputs), and none of the amendments tested could immobilize all targeted elements.10.
Yong Gao Tingting Li Yun Zhao Wei Liu Maolin Wang 《Genetic Resources and Crop Evolution》2010,57(4):481-485
A novel dwarf mutant of Brassica napus L. em. Metzg., named NDF-1, was derived from a high doubled haploid line ‘3529’ of which seeds were jointly treated with chemical inducers and fast
neutron bombardment. The germination results showed that the germination of NDF-1 was insensitive in response to exogenous gibberellic acid 3 (GA3). The studies on growth response to exogenous GA3 showed that NDF-1 seeding has at least 10-fold insensitivity than the wild-type. Moreover, no matter what concentrations of GA3 were added to the seedlings and adult plants, the NDF-1 could not restore the wild type phenotype. These results indicated that the B. napus dwarf mutant NDF-1 was GA-insensitive mutant. The histological observations showed that the key reason of leading NDF-1 to dwarf was the reduction of hypocotyls and stems cell numbers. 相似文献
11.
Radha Rani Priyanka Padole Asha Juwarkar Tapan Chakrabarti 《Water, air, and soil pollution》2012,223(3):1383-1392
Over 5 days, Brassica juncea removed 54% of the highly toxic insecticide phorate from the medium with the formation of phorate sulfoxide in small quantity.
The loss of phorate from the medium followed first-order kinetics. The half-life of phorate disappearance from water decreased
by ~4.5-fold in the presence of B. juncea. Mild phorate phytotoxicity was evident from the elevated activities of the antioxidative enzymes like glutathione-disulfide
reductase, glutathione S-transferase, superoxide dismutase, and catalase in the plants. Nevertheless, the ubiquitous antioxidative
peroxidase was not significantly increased, nor the total glutathione content, due to phorate exposure. Phosphotriester bond
hydrolysis and glutathione S-transferase-mediated conjugation seemed to be the key reactions for phorate metabolism by B. juncea. From the limited information available, for the first time, a tentative mapping of phytotransformation pathways was performed. 相似文献
12.
The genus Arachis is divided into nine taxonomic sections. Section Arachis is composed of annual and perennial species, while section Heteranthae has only annual species. The objective of this study was to investigate the genetic relationships among 15 Brazilian annual
accessions from Arachis and Heteranthae using RAPD markers. Twenty-seven primers were tested, of which nine produced unique fingerprintings for all the accessions
studied. A total of 88 polymorphic fragments were scored and the number of fragments per primer varied from 6 to 17 with a
mean of 9.8. Two specific markers were identified for species with 2n = 18 chromosomes. The phenogram derived from the RAPD data corroborated the morphological classification. The bootstrap analysis
divided the genotypes into two significant clusters. The first cluster contained all the section Arachis species, and the accessions within it were grouped based upon the presence or absence of the ‘A’ pair and the number of chromosomes.
The second cluster grouped all accessions belonging to section Heteranthae. 相似文献
13.
Lihua Yao Xiaoyan Zheng Danying Cai Yuan Gao Kun Wang Yufen Cao Yuanwen Teng 《Genetic Resources and Crop Evolution》2010,57(6):841-851
A total of 8117 suitable SSR-contaning ESTs were acquired by screening from a Malus EST database, among which dinudeotide SSRs were the most abundant repeat motif, within which, CT/TC followed by AG/GA were
predominant. Based on the suitable sequences, we developed 147 SSR primer pairs, of which 94 pairs gave amplifications within
the expected size range while 65 pairs were found to be polymorphic after a preliminary test. Eighteen primer pairs selected
randomly were further used to assess genetic relationship among 20 Malus species or cultivars. As a result, these primers displayed high level of polymorphism with a mean of 6.94 alleles per locus
and UPGMA cluster analysis grouped twenty Malus accessions into five groups at the similarity level of 0.6800 that were largely congruent to the traditional taxonomy. Subsequently,
all of the 94 primer pairs were tested on four accessions of Pyrus to evaluate the transferability of the markers, and 40 of 72 functional SSRs produced polymorphic amplicons from which 8
SSR loci selected randomly were employed to analyze genetic diversity and relationship among a collection of Pyrus. The 8 primer pairs produced expected bands with the similar size in apples with an average of 7.375 alleles per locus. The
observed heterozygosity of different loci ranged from 0.29 (MES96) to 0.83 (MES138), with a mean of 0.55 which is lower than 0.63 reported in genome-derived SSR marker analysis in Pyrus. The UPGMA dendrogram was similar to the previous results obtained by using RAPD and AFLP markers. Our results showed that
these EST-SSR markers displayed reliable amplification and considerable polymorphism in both Malus and Pyrus, and will contribute to the knowledge of genetic study of Malus and genetically closed genera. 相似文献
14.
Jiangbing Xu Youzhi Feng Yanling Wang Xiaosan Luo Jianwu Tang Xiangui Lin 《Journal of Soils and Sediments》2016,16(3):916-923
Purpose
The extract of Stevia residue is an ideal substitute for cultivation of the purple nonsulfur bacterium, like Rhodopseudomonas palustris (R. palustris). But the influence of R. palustris grown under residue extract on its downstream application is still not well-characterized. The objective of this study was to assess the effect of foliar spray of R. palustris grown under Stevia residue extract on the plant growth and soil microbial properties.Materials and methods
A pot experiment was carried out under the greenhouse condition, consisting of four treatments varying in the sprayed substances: sterilized water (control), R. palustris grown under the chemical medium supplemented with L-tryptophan (SyT), R. palustris grown under Stevia residue extract supplemented with L-tryptophan (ExT), and R. palustris grown under Stevia residue extract supplemented with NH4Cl (ExT). The net photosynthesis rate of the uppermost leaves was measured with a portable photosynthesis system. Soil microbial activity was analyzed by microcalorimetry. Soil bacterial community components were determined by real-time quantitative PCR (qPCR) and high-throughput sequencing techniques.Results and discussion
Compared with SyT, the R. palustris grown under Stevia residue extract not only improved the plant biomass and the net photosynthetic rate to a large extent, but also increased soil microbial metabolic activity and altered community compositions as well. The treatments receiving R. palustris, especially ExT and ExN, increased the relative abundances of some functional guilds involved in C turnover and nutrient cycling in soil, including Acidobacteria, Actinobacteria, Proteobacteria, Gemmatimonadaetes, Nitrospirae, and Planctomycetes.Conclusions
R. palustris grown under the Stevia residue extract showed advantages over that under the chemical medium on both plant growth and soil microbial properties. One of the possible reasons could result from the increases in microbial activity and several bacterial keystone guilds involved into C and nutrient cycling, both of which potentially contribute to the improved plant growth. The results would be conducive to the downstream application of R. palustris in an economical way.15.
Complete sequences of transcribed spacers and introns from the trnT trnF region of chloroplast DNA (cp DNA) were generated from Musaceae species to establish the phylogenetic relationships among
3 species of Ensete including the economically important Ensete ventricosum (Welw.) Cheesman and 13 species of Musa. Parsimony analysis and pair wise distance data produced a single tree, with Ensete and Musa as clearly distinguished clades. Six Musa and three Ensete clades were generated. The topology of these clades did not change when the data were split into spacers and introns, although
the split resulted in poor bootstrap support. Removing a hotspot from the entire data set improved clade support. The clades
produced are discussed with reference to existing taxonomic and phylogenetic treatments. In contrast to previous suggestions,
most of the Rhodochlamys species that we investigated clustered together with strong support establishing their distinctiveness
from the Musa species studied. Ensete glaucum (Roxb.) Cheesman and Musa beccartii Simmonds appear to represent ancestral forms of Ensete and Musa, respectively for the presently studied species, and both genera have a common ancestor that is yet to be established. Our
data also show that E. ventricosum cannot be reduced to E. glaucum, nor can E. gilleti (De Wild.) Cheesman be reduced to E. ventricosum, as some authorities have suggested. Ensete gilleti or a species very close to it appears to be the ancestral species of E. ventricosum. 相似文献
16.
Ying Wang BoWen Zhang NanJun Chen Can Wang Su Feng Heng Xu 《Journal of Soils and Sediments》2018,18(6):2136-2147
Purpose
The subjects of this study were to investigate the remediating potential of the co-cultivation of Pleurotus eryngii and Coprinus comatus on soil that is co-contaminated with heavy metal (cadmium (Cd)) and organic pollutant (endosulfan), and the effects of the co-cultivated mushrooms on soil biochemical indicators, such as laccase enzyme activity and bacterial counts.Materials and methods
A pot experiment was conducted to investigate the combined bioremediation effects on co-contaminated soil. After the mature fruiting bodies were harvested from each pot, the biomass of mushrooms was recorded. In addition, bacterial counts and laccase enzyme activity in soil were determined. The content of Cd in mushrooms and soil was detected by the flame atomic absorption spectrometry (FAAS), and the variations of Cd fractions in soil were determined following the modified BCR sequential extraction procedure. Besides, the residual endosulfan in soil was detected by gas chromatography-mass spectrometry (GC-MS).Results and discussion
The results indicated that co-cultivation of P. eryngii and C. comatus exerted the best remediation effect on the co-contaminated soil. The biomass of mushroom in the co-cultivated group (T group) was 1.57–13.20 and 19.75–56.64% higher than the group individually cultivated with P. eryngii (P group) or C. comatus (C group), respectively. The concentrations of Cd in the fruiting bodies of mushrooms were 1.83–3.06, 1.04–2.28, and 0.67–2.60 mg/kg in T, P, and C groups, respectively. Besides, the removal rates of endosulfan in all treatments exceeded 87%. The best bioremediation effect in T group might be caused by the mutual promotion of these two kinds of mushrooms.Conclusions
The biomass of mushroom, laccase activity, bacterial counts, and Cd content in mushrooms were significantly enhanced, and the dissipation effect of endosulfan was slightly higher in the co-cultivated group than in the individually cultivated groups. In this study, the effect of co-cultivated macro fungi P. eryngii and C. comatus on the remediation of Cd and endosulfan co-contaminated soil was firstly reported, and the results are important for a better understanding of the co-remediation for co-contaminated soil.17.
There is a need to understand whether weed genetic diversity is the same among different populations, especially between those
exposed to herbicide selection and other without exposure history. Inter-simple sequence repeat (ISSR) were used to assess
level and patterns of genetic diversity in wild Brassica juncea (L.) Czern. et Coss. populations. A total of 93 plants from 24 wild populations in China were analysed by eight primers resulting
in 86 highly reproducible ISSR bands. The analysis of molecular variance (AMOVA) with distances among individuals corrected
for the dominant nature of ISSRs showed that most of the variation (54.09%) occurred among populations, and the remaining
45.91% variance was attributed to differences among individuals within populations. The high differentiation was, perhaps,
due to limited gene flow (Nm < 1.0) of this species. Though highest gene diversity was observed in resistant B. juncea population, the overall distribution of diversity across China was not geographic dependent. High F
ST value (0.541) corroborated AMOVA partitioning and provided significant evidence for population differentiation in wild B. juncea. UPGMA cluster analyses, based on Nei’s genetic distance, revealed grouping pattern geographically. Based on these results,
the factors affect weed population genetic diversity and implication for herbicide resistance evolution were discussed in
the context of transgenic crops advent and increasing herbicide usage in China. 相似文献
18.
Vivian Silva Lira Ingritt Caroline Moreira Paulo Sérgio Tonello Armando A. Henriques Vieira Renata Fracácio 《Water, air, and soil pollution》2017,228(1):49
Bodies of water contaminated by cyanobacteria and their neuro- and hepatotoxins have caused environmental and public health issues all over the world. Therefore, determining safe concentrations in water for multiple uses to protect aquatic biota and identify forms of remediation are of broad interest. In this study, we isolated strains of the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii, which produce microcystin (MC) and saxitoxin (STX), respectively. Ecotoxicological tests using suspensions of lysed lyophilizated cells with concentrations of toxins equivalent to those permitted by legislation for potability (1 μg L?1 for MC and 3 μg L?1 for STX) did not result in significant mortality of the model organism, Ceriodaphnia dubia, where as concentrations five times greater resulted in decreased survival for both toxins. However, reproduction was significantly reduced even in the lower concentrations, indicating that the currently permitted standards are not safe for environmental protection. When cyanotoxins were treated with ultrasound, mortalities were no longer significant, independent of concentrations. Although reproduction was still lower in relation to the control, it was significantly higher when compared to the results obtained before ultrasound. Ultrasound has been previously applied to cyanobacteria cell lysis, but this is the first study to investigate the ecotoxicological effects of ultrasound on cyanotoxins. Using new test organisms and different times and potency of sonication will permit the development of more efficient techniques for the remediation of these toxins and the development of more adequate parameters for the protection of aquatic life. 相似文献
19.
In a Robinia-pseudoacacia-dominated coastal forest in Tottori prefecture Japan, the growth and survival of Pinus thunbergii seedlings and the natural regeneration of P. thunbergii was disturbed by R. pseudoacacia. In order to improve the growth of P. thunbergii seedling in the Tottori sand dune, we tried to find a mycorrhiza helper bacteria (MHB) from P. thunbergii mycorrhizosphere in a Tottori sand dune. Two MHB, Ralstonia sp. and Bacillus subtilis, were selected from the nine bacterial species isolated from the mycorrhizosphere of P. thunbergii. The bacterial effect on the ectomycorrhizal fungus Suillus granulatus was investigated by confrontation assay and a microcosm experiment. The confrontation assay showed that Ralstonia sp. promoted the hyphal growth of S. granulatus. Moreover, the S. granulatus–P. thunbergii symbiosis was significantly stimulated by Ralstonia sp. and B. subtilis. Ralstonia sp. and B. subtilis were regarded as MHB associated with P. thunbergii. This is the first report of Ralstonia sp. as an MHB. 相似文献
20.
Chinnaswamy Appunu Narayanasamy Sasirekha Vaiyapuri Ramalingam Prabavathy Sudha Nair 《Biology and Fertility of Soils》2009,46(1):57-63
The diversity among 269 rhizobia isolated from naturally occurring root nodules of soybean collected from two different agro-ecological
regions of India, based on RFLP and sequences of the intergenic spacer (IGS) between the 16S and 23S rRNA genes, growth rate,
and indole acetic acid production, revealed their significant, site-dependent genomic diversity. Among these bacteria, nine
IGS genotypes were identified with two endonucleases. They were distributed into five divergent lineages by sequence analysis
of each IGS representative strain, i.e., (1) comprising IGS genotypes I, II, III, and reference Bradyrhizobium yuanmingense; (2) with genotype IV and strains of unclassified bradyrhizobia genomic species; (3) including genotypes V, VI, and Bradyrhizobium liaoningense; (4) with IGS genotype VII and Bradyrhizobium elkanii strains; and (5) comprising IGS genotypes VIII, IX, and different Ensifer genus bacteria. Host-specificity test revealed that all rhizobia-nodulated soybean and cowpea and only part of them formed
nodules on Arachis hypogeae and Cajanus cajan. The great diversity of soybean nodulators observed in this study emphasises that Indian soil is an important reservoir of
nitrogen-fixing rhizobia. 相似文献