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1.
Liske Versieren Elke Smets Karel De Schamphelaere Ronny Blust Erik Smolders 《Plant and Soil》2014,381(1-2):131-142
Background and aims
The biotic ligand model (BLM) is a bioavailability model for metals based on the concept that toxicity depends on the concentration of metal bound to a biological binding site; the biotic ligand. Here, we evaluated the BLM to interpret and explain mixture toxicity of metals (Cu and Zn).Methods
The mixture toxicity of Cu and Zn to barley (Hordeum vulgare L.) was tested with a 4 days root elongation test in resin buffered nutrient solutions. Toxicity of one toxicant was tested in presence or absence of a low effect level of the other toxicant or in a ray design with constant toxicant ratios. All treatments ran at three different Ca concentrations (0.3, 2.2 and 10?mM) to reveal ion interaction effects.Results
The 50 % effect level (EC50) of one metal, expressed as the free ion in solution, significantly (p?<?0.05) increased by adding a low level effect of the other metal at low Ca. Such antagonistic interactions were smaller or became insignificant at higher Ca levels. The Cu EC10 was unaffected by Zn whereas the Zn EC10 increased by Cu at low Ca. These effects obeyed the BLM combined with the independent action model for toxicants.Conclusions
The BLM model explains the observed interactions by accounting for competition between both metals free ions and Ca2+ at the Cu and Zn biotic ligands. The implications of these findings for Cu/Zn interactions in soil are discussed. 相似文献2.
Effects of soil acidity and water stress on corn and soybean performance under a no-till system 总被引:1,自引:0,他引:1
Helio Antonio Wood Joris Eduardo Fávero Caires Angelo Rafael Bini Danilo Augusto Scharr Adriano Haliski 《Plant and Soil》2013,365(1-2):409-424
Background and Aims
Field studies have demonstrated that aluminum (Al) toxicity is low in no-till systems during cropping seasons that have adequate and well-distributed rainfall. This study evaluated the performance of corn (Zea mays L.) and soybean (Glycine max L. Merrill) on an acid loamy soil under a long-term no-till system, in response to surface liming and as affected by genotypic tolerance to Al and water stress.Methods
A field trial examined the effect of surface application of lime (0, 4, 8, and 12 Mg ha?1) on no-till corn and soybean nutrition and yield. Trials were also carried out in undisturbed soil columns taken from the unlimed and limed plots. Two hybrids/cultivars of corn and soybean, one sensitive and the other moderately sensitive to Al were grown at two soil moisture levels with and without water stress (50 % and 80 % water filled pore space).Results
Alleviating soil acidity by liming improved nutrition and increased grain yields of corn and soybean. The benefits of liming on root length density, nutrient uptake and shoot biomass production of corn and soybean were more pronounced in Al-sensitive genotypes under water stress.Conclusions
The results suggest that plants exposed to drought stress under no-till systems are more affected by Al toxicity. 相似文献3.
Venus Elec Celsa A. Quimio Rhulyx Mendoza Andres Godwin C. Sajise Sarah E. J. Beebout Glenn B. Gregorio Rakesh Kumar Singh 《Plant and Soil》2013,372(1-2):253-264
Background and aims
Iron toxicity decreases rice (Oryza sativa) grain yield especially in acid soils after flooding. Our aim was to establish a high-throughput screening technique using nutrient solution culture for identifying Fe-toxicity-tolerant genotypes.Methods
Varying levels of Fe, pH, and chelators in Yoshida nutrient solution culture were tested to maintain sufficient Fe2+ concentration over time to optimize the severity of Fe toxicity stress for distinguishing between a tolerant (Azucena) and sensitive (IR64) genotype. The optimized solution was tested on 20 diverse genotypes in the greenhouse, with measurement of leaf bronzing scores and plant growth characteristics at the seedling stage. The same 20 genotypes were grown to maturity in a field with natural Fe toxicity stress, with measurement of seedling-stage leaf bronzing scores and grain yield to determine their inter-relationship.Results
Optimized nutrient solution conditions were 300 mg L?1 Fe supplied as Fe2+ at pH 4.0 with a 1:2 molar ratio of Fe:EDTA, which maintained sufficient Fe2+ stress over 5 days. The highest correlation of nutrient solution phenotypic data with field grain yield was found with leaf bronzing scores at 4 weeks, with a Pearson r of 0.628 for simple association and a Spearman corrected r of 0.610 for rank association (P?<?0.01) using 20 diverse rice genotypes with proven Fe toxicity tolerance reaction. The Leaf bronzing scores at 4 weeks in nutrient culture solution were also found highly correlated with LBS under natural field stress after 8 weeks that had highest correlation with grain yield under stress.Conclusion
This culture solution-based standardized screening technique can be used in plant breeding programs as a high-throughput technique to identify genotypes tolerant to Fe toxicity. 相似文献4.
Hongyan Sheng Deven R. See Timothy D. Murray 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(10):2085-2093
Key message
This study identified three QTL conferring resistance to Oculimacula acuformis in Aegilops longissima and their associated markers, which can be useful in marker-assisted selection breeding for eyespot resistance.Abstract
Oculimacula acuformis is one of two species of soilborne fungi that cause eyespot of wheat, the other being Oculimacula yallundae. Both pathogens can coexist in the same field and produce elliptical lesions on stem bases of wheat that are indistinguishable. Pch1 and Pch2 are the only two eyespot resistance genes readily available to wheat breeders, but neither provides complete control. A new source of eyespot resistance was identified from Aegilops longissima (2n = 14, SlSl), a wild relative of wheat. Three QTL for resistance to O. acuformis were mapped in chromosomes 1Sl, 3Sl, and 5Sl using a recombinant inbred line population developed from the cross Ae. longissima accessions PI 542196 (R) × PI 330486 (S). The three QTL explained 66 % of phenotypic variation by β-glucuronidase score (GUS) and 84 % by visual rating. These QTL had LOD values of 10.6, 8.8, and 6.0 for GUS score, and 16.0, 10.0, and 13.0 for visual rating. QTL associated with resistance to O. acuformis have similar chromosomal locations as some for resistance to O. yallundae, except that a QTL for resistance to O. yallundae was found in chromosome 7Sl but not for O. acuformis. Thus, it appears that some genes at the same locus in Ae. longissima may control resistance to both eyespot pathogens. QTL effective against both pathogens will be most useful for breeding programs and have potential to improve the effectiveness and genetic diversity of eyespot resistance. 相似文献5.
Rainer Rees Brett H. Robinson Michael W. H. Evangelou Eberhard Lehmann Rainer Schulin 《Plant and Soil》2012,358(1-2):403-415
Background
Poplars accumulate inordinate amounts of B in their leaves and are candidate plants for the remediation of B contaminated soil. We aimed to determine the effect of heterogeneous B distribution in soil by comparing the growth and B accumulation of young Populus tremula trees growing in soil with heterogeneous and homogeneous B distributions.Methods
The first of two experiments focused on the tolerance and B accumulation of P. tremula under heterogeneous soil B distributions, while the second was designed to study fine root growth under such conditions in detail.Results
Growth and B accumulation of P. tremula were unaffected by the spatial distribution of B. Root and shoot growth were both reduced simultaneously when leaf B concentrations increased above 800 mg kg?1. In the heterogeneous soil B treatments, root growth was more reduced in spiked soil portions with B concentrations >20 mg kg?1. Fine root length growth was stronger inhibited by B stress than secondary growth.Conclusions
The root growth responses of P. tremula to B are primarily a systemic effect induced by shoot B toxicity and local toxicity effects on roots become dominant only at rather high soil B concentrations. Local heterogeneity in soil B should have little influence on the phytoremediation of contaminated sites. 相似文献6.
Effect of selenium fertilization on the accumulation of cadmium and lead in rice plants 总被引:4,自引:0,他引:4
Ying Hu Gareth John Norton Guilan Duan Yanchao Huang Yunxia Liu 《Plant and Soil》2014,384(1-2):131-140
Background and Aims
The accumulation of cadmium and lead in rice (Oryza sativa L.) grains is a potential threat to human health. In this study, the effect of selenium fertilization on the uptake and translocation of cadmium and lead in rice plants was investigated.Methods
Rice plants were cultivated using cadmium and lead contaminated soils with selenium addition at three concentrations (0, 0.5 and 1 mg kg?1). At maturity, plants were harvested, and element concentrations in rice tissues were analyzed by using ICP-MS.Results
Selenium application significantly increased selenium accumulation in rice grain, and markedly decreased cadmium and lead concentrations in rice tissues. In brown rice grains, selenium application reduced cadmium concentrations by 44.4 %, but had no significant effect on lead accumulation. Selenium application significantly decreased metal mobility in soils, at 0.5 mg kg?1 treatment, the translocation factor of cadmium and lead from soil to iron plaque decreased by 71 and 33 % respectively.Conclusions
The mechanism of selenium mitigating of heavy metal accumulation in rice could be decreasing metal bioavailability in soil. Selenium fertilization could be an effective and feasible method to enrich selenium and reduce cadmium levels in brown rice. 相似文献7.
Maxime Séleck Jean-Philippe Bizoux Gilles Colinet Michel-Pierre Faucon Arielle Guillaume Pierre Meerts Julien Piqueray Grégory Mahy 《Plant and Soil》2013,373(1-2):455-469
Aims
Define the chemical factors structuring plant communities of three copper-cobalt outcrops (Tenke-Fungurume, Katangan Copperbelt, D. R. Congo) presenting extreme gradients.Methods
To discriminate plant communities, 172 vegetation records of all species percentage cover were classified based on NMDS and the Calinski criterion. Soil samples were analyzed for 13 chemical factors and means compared among communities with ANOVA. Partial canonical correspondence analysis (pCCA) was used to determine amount of variation explained individually by each factor and site effect.Results
Seven communities were identified. Six of the studied communities were related to distinct sites. Site effect (6.0 % of global inertia) was identified as the most important factor related to plant communities’ variation followed by Cu (5.5 %), pH (3.6 %) and Co (3.5 %). Unique contribution of site effect (3.8 %) was higher than that of Cu (1.1 %) and Co (1.0 %).Conclusions
In restoration, not only Cu and Co contents will be important to maintain vegetation diversity, attention should also be given to co-varying factors potentially limiting toxicity of metals: pH, organic matter, Ca and Mn. Physical parameters were also identified as important in the creation of adequate conditions for diverse communities. Further studies should focus on the effect of physical parameters and geology. 相似文献8.
Dörte Randewig Domenica Hamisch Monika Eiblmeier Christian Boedecker Jürgen Kreuzwieser Ralf R. Mendel Robert Hänsch Cornelia Herschbach Heinz Rennenberg 《Trees - Structure and Function》2014,28(2):399-411
Key Message
The critical level for SO 2 susceptibility of Populus × canescens is approximately 1.2 μL L ?1 SO 2 . Both sulfite oxidation and sulfite reduction and assimilation contribute to SO 2 detoxification.Abstract
In the present study, uptake, susceptibility and metabolism of SO2 were analyzed in the deciduous tree species poplar (Populus × canescens). A particular focus was on the significance of sulfite oxidase (SO) for sulfite detoxification, as SO has been characterized as a safety valve for SO2 detoxification in herbaceous plants. For this purpose, poplar plants were exposed to different levels of SO2 (0.65, 0.8, 1.0, 1.2 μL L?1) and were characterized by visible injuries and at the physiological level. Gas exchange parameters (stomatal conductance for water vapor, CO2 assimilation, SO2 uptake) of the shoots were compared with metabolite levels (sulfate, thiols) and enzyme activities [SO, adenosine 5′-phosphosulfate reductase (APR)] in expanding leaves (80–90 % expanded). The critical dosage of SO2 that confers injury to the leaves was 1.2 μL L?1 SO2. The observed increase in sulfur containing compounds (sulfate and thiols) in the expanding leaves strongly correlated with total SO2 uptake of the plant shoot, whereas SO2 uptake rate was strongly correlated with stomatal conductance for water vapor. Furthermore, exposure to high concentration of SO2 revealed channeling of sulfite through assimilatory sulfate reduction that contributes in addition to SO-mediated sulfite oxidation to sulfite detoxification in expanding leaves of this woody plant species. 相似文献9.
10.
Qianqian Wang Yixiang Xu Jiaqi Xu Xudong Wang Chen Shen Yan Zhang Xiufeng Liu Boyang Yu Jian Zhang 《Biotechnology letters》2017,39(8):1229-1235
Objectives
To characterize glycosyltransferases from Bacillus subtilis ATCC 6633 and investigate their substrate specificity towards plant polyphenols.Results
Among the cloned and expressed six UDP-glycosyltransferases (BsGT1-6), BsGT-1 showed activity with a wide range of polyphenols: morin, quercetin, alizarin, rehin, curcumin and aloe emodin. The gene of BsGT-1 has an ORF of 1206 bp encoding 402 amino acids. The recombinant enzyme was purified to homogeneity by Ni–NTA affinity chromatograph, and its biochemical characteristics were identified by HPLC–UV/MS, 1H-NMR and 13C-NMR. BsGT-1 has an MW of approx. 46 kDa as indicated by SDS-PAGE; its activity was optimal at 40 °C and pH 8.5. The Km value of BsGT-1 towards morin was 110 μM.Conclusions
BsGT-1 from B. subtilis was cloned. It had high catalytic capabilities towards polyphenols which would make it feasible for the structural modification of polyphenols.11.
Siyuan Tao Lihong Sun Chunyan Ma Linlin Li Guangzhe Li Lin Hao 《Plant and Soil》2013,372(1-2):309-318
Aims
Phytoremediation is an emerging strategy for the removal of heavy metal contaminants. However, one of the prerequisite is to understand adequately plant resistant mechanisms. The present study was performed to assess the role of endogenous SA in plant response to Pb or Cd using wild-type (wt) Arabidopsis and its SA-accumulating mutant snc1, SA-reducing transgenic line nahG, SA signal-blocking npr1-1, and snc1/nahG (i.e. expression of nahG in snc1 plant) with a comparable level of SA to the wt.Methods
Plants were grown hydroponically in controlled conditions. For heavy metal exposure, Pb2+ or Cd2+ at final concentrations of 50 μM, 100 μM, and 150 μM, respectively, was added to the culture solution. Unless otherwise indicated, samples were harvested after 7 d of exposure, and used for analyses.Results
Compared to the wt level, the high endogenous SA significantly potentiated Pb- and Cd-induced plant growth retardation, whereas SA deficiency decreased the growth inhibition, and SA signaling blockage also had some protective effect. The expression of nahG in snc1 plant mitigated effectively the growth inhibition. The SA-related mechanism was involved in redox homeostasis, photosynthetic process, and soluble matter accumulation.Conclusions
These results suggest that Pb- or Cd-induced phytotoxicity in Arabidopsis was intensified by elevated endogenous SA, whereas ameliorated by reduced SA. 相似文献12.
Jitendra Wagh Praveena Bhandari Sonal Shah G. Archana G. Naresh Kumar 《Plant and Soil》2014,383(1-2):73-86
Background and aims
Herbaspirillum seropedicae Z67, nitrogen fixing endophyte, significantly promotes the growth of cereals. Organic acid secreting nitrogen fixing rhizobacteria have better plant growth promotion abilities due to mineral phosphate solubilization.Method
Plasmids pAB7, pJNK3 and pJNK4 containing Escherichia coli cs (gltA), NADH insensitive cs (gltA1), and citrate operon consisting of gltA1 gene along with Salmonella typhimurium Na+ dependent citrate transporter (citC) gene under constitutive lac promoter were constructed in broad host range plasmid pUCPM18-Kmr. The plasmid transformants of H. seropedicae Z67 were obtained by electroporation.Results
Hs (pAB7) and Hs (pJNK3) had increased CS activity but citric acid secretion was not significant. Hs (pJNK3) secreted 45 mM acetic acid while Hs (pJNK4) secreted 2.7 mM citric and 51 mM acetic acids. Hs (pJNK3) and Hs (pJNK4) released 80 μM and 110 μM amount of P from rock phosphate, respectively, in buffered medium under both aerobic and micro aerobic conditions. These transformants showed better plant growth promoting factors. Upon inoculation to rice plants (Gujarat – 17), increase of Fresh weight, Dry weight N, P and K content was observed.Conclusion
Thus the study demonstrates that artificial citrate operon in H. seropedicae Z67 enhances phosphate solubilization and plant growth promotion abilities. 相似文献13.
Assessment of nitrate leaching loss on a yield-scaled basis from maize and wheat cropping systems 总被引:9,自引:0,他引:9
Background and aims
It is so far a gap in knowledge to assess nitrate (NO3 ?) leaching loss linking with crop yield for a given cereal cropping system.Methods
We conducted a meta-analysis on 32 published studies reporting both NO3 ? leaching losses and crop yields in the maize (N?=?20) and wheat (N?=?12) systems.Results
On average, 22 % and 15 % of applied fertilizer N to wheat and maize systems worldwide are leached in the form of NO3 ?, respectively. The average area-scaled NO3 - leaching loss for maize (57.4 kg N ha?1) was approx. two times higher than for wheat (29.0 kg N ha?1). While, if scaled to crop yields, the average yield-scaled NO3 ? losses were comparable between maize (5.40 kg N Mg?1) and wheat (5.41 kg N Mg?1) systems. Across all sites, the lowest yield-scaled NO3 ? leaching losses were observed at slightly suboptimal fertilization rates, corresponding to 90 % and 96 % of maximum maize or wheat yields, respectively.Conclusions
Our findings suggest that small adjustments of agricultural N management practices can effectively reduce yield-scaled NO3 ? leaching losses. However, further targeted field experiments are still needed to identify at regional scale best agricultural management practices for reducing yield-scaled NO3 ? leaching losses in maize and wheat systems. 相似文献14.
Context
In acidic forest soils, aluminium can alter tree health due to its potential toxicity. Aluminium phytotoxicity is mainly influenced by its chemical form and its availability.Methods
As physical-chemical indicators of Al toxicity in soil, Al speciation in soil solutions and in the exchange complex was measured in the rhizosphere and the bulk soil of two tree species (Norway spruce (Picea abies (L.) Karst.) and European Beech (Fagus sylvatica L.) in an acidic soil and in 4 months (November, February, May and August) representing the four seasons in a year.Results
In the bulk soil, Al toxicity was generally higher under Norway spruce than under beech. Furthermore, temporal changes in Al behaviour were identified under Norway spruce but not under beech. The monomeric Al in the soil solutions and the exchangeable Al in the solid soil increased significantly in February under Norway spruce and were positively correlated with nitrate concentration, suggesting that nitrate influence Al speciation and mobility under Norway spruce. In the rhizosphere, Al toxicity was restricted through Al complexation by organic compounds and by nutrient contents independently from the season. The ecological importance of the rhizosphere in Al detoxification is discussed.Conclusions
This study suggests that plant specific differences as well as seasonal changes in plant physiology, microbial activity and microclimatology influence aluminum toxicity in acid forest soils. 相似文献15.
E. D. Schulze D. Nicolle A. Boerner M. Lauerer G. Aas I. Schulze 《Trees - Structure and Function》2014,28(4):1125-1135
Key message
Eucalyptus and Acacia species were surprisingly similar with respect to variations in δ 13 C, δ 15 N. Both genera respond with speciation and associated changes in leaf structure to drought.Abstract
Stable carbon and nitrogen isotope ratios (δ13C and δ15N) in leaves of eucalypts (Corymbia and Eucalyptus) and Acacia (and some additional Fabaceae) species were investigated together with specific leaf area (SLA), leaf nitrogen (N) and leaf phosphorous (P) concentration along a north–south transect through Western Australia covering winter- and summer-dominated rainfall between 100 and 1,200 mm annually. We investigated 62 eucalypts and 78 woody Fabaceae species, mainly of the genus Acacia. Leaf δ13C values of Eucalyptus and Acacia species generally increased linearly with latitude from ?29.5 ± 1.3 ‰ in the summer-dominated rainfall zone (15°S–18°S) to about ?25.7 ± 1.1 ‰ in the winter-dominated rainfall zone (29°S–31°S). δ15N increased initially with southern latitudes (0.5 ± 1.6 ‰ at 15°S; 5.8 ± 3.3 ‰ at 24–29°S) but decreased again further South (4.6 ± 3.5 ‰ at 31°S). The variation in δ13C and δ15N was probably due to speciation of Eucalyptus and Acacia into very local populations. There were no species that were distributed over the whole sampling area. The variation in leaf traits was larger between species than within species. Average nitrogen concentrations were 11.9 ± 1.05 mg g?1 in Eucalyptus, and were 18.7 ± 4.1 mg g?1 in Acacia. Even though the average nitrogen concentration was higher in Acacia than Eucalyptus, δ15N gave no clear indication for N2 fixation in Acacia. In a multiple regression, latitude (as a surrogate for rainfall seasonality), mean rainfall, leaf nitrogen concentration, specific leaf area and nitrogen fixation were significant and explained 69 % of the variation of δ13C, but only 36 % of the variation of δ15N. Higher nitrogen and phosphorus concentration could give Acacia an advantage over Eucalyptus in arid regions of undefined rainfall seasonality. 相似文献16.
A recombinant l-fucose isomerase from Caldicellulosiruptor saccharolyticus was purified as a single 68 kDa band with an activity of 76 U mg?1. The molecular mass of the native enzyme was 204 kDa as a trimer. The maximum activity for l-fucose isomerization was at pH 7 and 75°C in the presence of 1 mM Mn2+. Its half-life at 70°C was 6.1 h. For aldose substrates, the enzyme displayed activity in decreasing order for l-fucose, with a k cat of 11,910 min?1 and a K m of 140 mM, d-arabinose, d-altrose, and l-galactose. These aldoses were converted to the ketoses l-fuculose, d-ribulose, d-psicose, and l-tagatose, respectively, with 24, 24, 85, 55% conversion yields after 3 h. 相似文献
17.
Population structure and association mapping of yield contributing agronomic traits in foxtail millet 总被引:1,自引:0,他引:1
Sarika Gupta Kajal Kumari Mehanathan Muthamilarasan Swarup Kumar Parida Manoj Prasad 《Plant cell reports》2014,33(6):881-893
Key message
Association analyses accounting for population structure and relative kinship identified eight SSR markers ( p < 0.01) showing significant association ( R 2 = 18 %) with nine agronomic traits in foxtail millet.Abstract
Association mapping is an efficient tool for identifying genes regulating complex traits. Although association mapping using genomic simple sequence repeat (SSR) markers has been successfully demonstrated in many agronomically important crops, very few reports are available on marker-trait association analysis in foxtail millet. In the present study, 184 foxtail millet accessions from diverse geographical locations were genotyped using 50 SSR markers representing the nine chromosomes of foxtail millet. The genetic diversity within these accessions was examined using a genetic distance-based and a general model-based clustering method. The model-based analysis using 50 SSR markers identified an underlying population structure comprising five sub-populations which corresponded well with distance-based groupings. The phenotyping of plants was carried out in the field for three consecutive years for 20 yield contributing agronomic traits. The linkage disequilibrium analysis considering population structure and relative kinship identified eight SSR markers (p < 0.01) on different chromosomes showing significant association (R 2 = 18 %) with nine agronomic traits. Four of these markers were associated with multiple traits. The integration of genetic and physical map information of eight SSR markers with their functional annotation revealed strong association of two markers encoding for phospholipid acyltransferase and ubiquitin carboxyl-terminal hydrolase located on the same chromosome (5) with flag leaf width and grain yield, respectively. Our findings on association mapping is the first report on Indian foxtail millet germplasm and this could be effectively applied in foxtail millet breeding to further uncover marker-trait associations with a large number of markers. 相似文献18.
Wenjing Cui Zengxiu Shi Yueqin Fang Li Zhou Ning Ding Zhemin Zhou 《Biotechnology letters》2014,36(1):121-126
Purpose of work
We have elucidated the significance of three key amino acid residues of l-aspartate α-decarboxylase that act remotely from its cleavage site for its functional self-cleavage as well as for its catalytic activity. These results provide useful fundamental information for engineering l-aspartate α-decarboxylase. l-Aspartate α-decarboxylase (ADC) from Corynebacterium glutamicum, and encoded by panD, was cloned and expressed in Escherichia coli and then purified. Three amino acid residues were found to be related to ADC self-cleavage. Mutating R3 to either A, Q, N, L, D, or E produced only the unprocessed pro-enzyme. Although mutating R54 and Y58 into A or K and A or T, respectively, partly influenced ADC self-cleavage, the specific activity of each of the four ßmutants decreased to 3.5, 4, 2.4, and 2.6 U mg?1, respectively, compared with a specific activity of 690 U mg?1 for the wild-type enzyme. Thus, R3 triggers ADC self-cleavage and completes the modification of the active site with assistance by R54 and Y58. These results will help to engineer ADC for improved industrial applications. 相似文献19.