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1.
The effect of the arbuscular mycorrhizal (AM) fungus (Glomus versiforme) on iron contents by two citrus rootstocks (trifoliate orange [Poncirus trifoliata L. Raf] and red tangerine [Citrus reticulata Blanco]) was studied in sand culture under different pH conditions. Seeds were sown in a mixed substrate (perlite/sand, 1:1 [v/v]) inoculated with or without mycorrhizal inoculum. The experiment was carried out at four pH levels by applying nutrient solution at pH 5.0, 6.0, 7.0, or 8.0 to P. trifoliata and pH 5.2, 6.2, 7.2, or 8.2 to C. reticulata. No AM colonization was found in uninoculated control (NM) and plants, and root colonization in AM plants was depressed under iron deficiency at high pH. Colonization by G. versiforme led to higher dry weights of shoots compared with NM treatments, suggesting that G. versiforme enhanced plant growth. Higher concentration of chlorophyll and active iron, lower ratios of P/Fe and 50(10P+K)/Fe were present in AM plants than NM treatments. Nevertheless, G. versiforme improved root Fe (III) chelate reductase activity of P. trifoliata and C. reticulata. The data indicate that plant uptake and translocation of iron were enhanced and AM fungi may be considered as a potential tool for bioremediation of citrus iron deficiency.  相似文献   

2.
ABSTRACT

A pot experiment was carried out to investigate the tolerance of cucumber plants (Cucumis sativus L.) to root-knot nematode after inoculation with Glomus intraradices. Plants were inoculated with G. intraradices for four weeks and then transplanted in soil treated with Meloidogyne incognita for a further five weeks. The low phosphorus (P) loamy soil was amended with 50 and 100 mg P kg?1 soil. Mycorrhizal colonization increased shoot dry weight, shoot length, leaf numbers, root fresh weight and shoot P concentration, whereas nematode penetration and reproduction were significantly decreased. Similarly, P fertilization usually increased shoot growth and significantly decreased the number of galls and the number of egg masses and eggs per g root. Our results indicate that inoculation with G. intraradices and P fertilizer confer tolerance of cucumber plants to M. incognita by enhancing plant growth and by suppressing reproduction and/or galling of nematodes during the early stages of plant growth.  相似文献   

3.
Information about the interaction between arbuscular mycorrhizal fungi (AMF) and the false root-knot nematode Nacobbus aberrans (Thorne, 1935) Thorne & Allen, 1944 is scarce. The effect of Glomus intraradices Schenk & Smith on tomato (Lycopersicon esculentum L.) cv. Platense inoculated with nematode juveniles from Lisandro Olmos (Argentina) was studied under greenhouse conditions. Six treatments with five replications were performed. After 80 days, nematode reproduction and percentage of AMF colonization in roots were estimated. Some plant growth parameters were also measured. In general, plants with AMF and AMF plus nematodes grew as well as the control without AMF and without nematodes. Furthermore, G. intraradices was beneficial in reducing nematode-induced damage in roots (lower number of galls) as well as in having a suppressive effect on parasite reproduction. This is the first study on the use of G. intraradices as a possible strategy in the control of N. aberrans in tomato.  相似文献   

4.
This study investigated the interactions between two arbuscular mycorrhizal fungi (AMF) (Glomus aggregatum and Glomus mosseae) and a P-solubilizing fungus (Mortierella sp.), with respect to their effects on growth of Kostelelzkya virginica and urease, invertase, neutral phosphatase, alkaline phosphatase, and catalase activities of rhizosphere and bulk soils at different salinity levels (i.e., 0, 100, 200, and 300 mM NaCl). Percentage of AMF colonization, Mortierella sp. populations, pH, electrical conductivity, and available P concentration in soil were also determined. Combined inoculation of AMF and Mortierella sp. increased the percentage of AMF colonization and Mortierella sp. populations under salt stress (i.e., 100, 200, and 300 mM NaCl). The dual inoculation of Mortierella sp. with AMF (G. aggregatum or G. mosseae) had significant effects on shoot and root dry weights and available P concentrations, pH values, and electrical conductivities of rhizosphere and bulk soils under salt stress. The inoculation of Mortierella sp. significantly enhanced the positive effects of AMF on some enzyme activities (i.e., neutral phosphatase, alkaline phosphatase, and catalase in bulk soil; neutral phosphatase and urease in rhizosphere soil); on the contrary, it produced negative effects on urease activities in bulk soil and invertase activities in bulk and rhizosphere soils. The results indicated that the most effective co-inoculation was the dual inoculation with Mortierella sp. and G. mosseae, which may help in alleviating the deleterious effects of salt on plants growth and soil enzyme activities.  相似文献   

5.
Glasshouse experiments were conducted to assess the influence of arbuscular mycorrhizal (AM) fungi (Glomus mosseae and Gigaspora margarita) and organic fertilizers (cow dung, horse dung, goat dung and poultry manure) alone and in combination on the reproduction of the nematode Meloidogyne incognita and on growth and water loss of tomato. Meloidogyne incognita decreased water loss of tomato from the first week onwards after inoculation. AM fungi increased water loss of both nematode-infected and uninfected plants. Glomus mosseae was better at improving growth of tomato and reducing galling and nematode multiplication than G. margarita, but the rate of water loss was similar with both fungi. Addition of organic fertilizers improved growth of tomato, but decreased the rate of water loss. There was less galling and nematode multiplication with poultry manure, which improved tomato growth more than goat dung, while cow dung was the least effective organic fertilizer. Greatest plant growth and least nematode reproduction were observed in plants inoculated with M. incognita along with G. mosseae and poultry manure.  相似文献   

6.
The effect of salinity on the efficacy of two arbuscular mycorrhizal fungi, Glomus fasciculatum and G. macrocarpum, alone and in combination was investigated on growth, development and nutrition of Acacia auriculiformis. Plants were grown under different salinity levels imposed by 0.3, 0.5 and 1.0 S m-1 solutions of 1 M NaCl. Both mycorrhizal fungi protected the host plant against the detrimental effect of salinity. The extent of AM response on growth as well as root colonization varied with fungal species, and with the level of salinity. Maximum root colonization and spore production was observed with combined inoculation, which resulted in greater plant growth at all salinity levels. AM fungal inoculated plants showed significantly higher root and shoot weights. Greater nutrient acquisition, changes in root morphology, and electrical conductivity of soil in response to AM colonization was observed, and may be possible mechanisms to protect plants from salt stress.  相似文献   

7.
The effects of increasing levels of metals (10 and 20 mg of Cr kg-1 and 25 and 50 mg of Cd, Pb, and Ni kg-1 soil) and arbuscular mycorrhizal (AM) fungi Glomus intraradices on the yield, chemical composition of volatile oil, and metal accumulation in sweet basil (Ocimum basilicum L.) were investigated in a pot experiment. The shoot yield, content of essential oil, and root yield of sweet basil were increased by the application of low dose of Cd, Pb, and Ni as compared to control. The application of high level of metals had deleterious effect on the yield. In soil with low dose of metal applied, AM fungi inoculation significantly enhanced the metal concentration in shoots and had adverse effect on the yield, whereas in soil with high dose of metal applied, AM fungal inoculation reduced the metal concentration in shoot and had beneficial effect on the yield. The content of linalool in basil oil was decreased and that of methyl chavicol was increased by the application of Cr, Cd, and Pb in soil as compared to control. Similarly, the level of linalool and methyl chavicol was decreased and that of methyl eugenol was increased by the application of Ni as compared to control. However, AM fungal inoculation led to maintain the content of linalool, methyl chavicol, and methyl eugenol in volatile oil, which were either increased or decreased by the application of metals. We conclude that the AM–sweet basil symbiosis could be used as a novel approach to enhance the yield and maintain the quality of volatile oil of sweet basil under metal-contaminated soils.  相似文献   

8.
Benefits from the application of plant growth-promoting bacteria in agriculture largely depend on the complex interactions between several factors including the nature of fertilizers selected. This study was designed to determine the fine tuning between the inoculated bacteria and different fertilizers and their effect on the growth of lettuce plants (Lactuca sativa L.). Plant growth promotion by a novel species of the genus Azospirillum, namely A. rugosum IMMIB AFH-6, was tested by biochemical, bioassay, and greenhouse studies. The treatments used in the greenhouse study were; unfertilized control (Blank), half recommended dose of chemical fertilizer (1/2CF), full recommended dose of chemical fertilizer (1CF), pig manure fertilizer (PMF), pig manure fertilizer + half recommended dose of chemical fertilizer (PMF + 1/2CF), and pig manure fertilizer + full recommended dose of chemical fertilizer (PMF + 1CF). All these treatments when inoculated with A. rugosum IMMIB AFH-6 inoculation were, respectively, In-Blank, In-1/2CF, In-1CF, In-PMF, In-PMF + 1/2CF, and In-PMF + 1CF. Significant increase in plant biomass and shoot N, P, Ca, and Fe was shown in the In-Blank treatment. Plant growth in soil amended with PMF and A. rugosum IMMIB AFH-6 was significantly lower than in soil treated with the chemical fertilizer, but inoculation combined with chemical fertilizer significantly elevated the plant biomass. The In-PMF + 1/2CF treatment showed the highest yield. A. rugosum IMMIB AFH-6 facilitated the accumulation of trace minerals in higher concentrations when PMF was combined with 1CF. To examine the benefits of inoculation by A. rugosum IMMIB AFH-6, we have proposed a new type of data analysis which considers both biomass and nutrient content of plants. This new type of analysis has shown the importance of the mineral content of plant.  相似文献   

9.
A field experiment was carried out to compare the effectiveness of inoculation with three arbuscular mycorrhizal (AM) fungi, namely Glomus intraradices Schenck & Smith, Glomus deserticola (Trappe, Bloss. & Menge) and Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe, and the addition of Aspergillus niger‐treated dry olive cake (DOC) in the presence of rock phosphate, in increasing root nitrate reductase (NR) and acid phosphatase activities, mycorrhizal colonization, plant growth and nutrient uptake in Dorycnium pentaphyllum L. seedlings afforested in a semiarid degraded soil. Three months after planting, both the addition of fermented DOC and the mycorrhizal inoculation treatments had increased root NR activity significantly, particularly the inoculation with G. deserticola (by 75 per cent with respect to non‐inoculated plants), but they had no effect on root acid phosphatase. Mycorrhizal inoculation treatments with G. deserticola or G. mosseae on their own were even more effective than the addition of fermented DOC alone in improving the growth and (NPK) foliar nutrients of D. pentaphyllum plants. The combined treatment involving the application of microbially‐treated agrowastes and mycorrhizal inoculation with AM fungi, particularly with G. mosseae, can be proposed as a successful revegetation strategy for D. pentaphyllum in P‐deficient soils under semiarid Mediterranean conditions. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

10.
Ten leguminous trees, four exotic species (Australian Acacia) and six indigenous species (three Sahelian Acacia spp. and three Sesbania spp.), were grown for 4 months in a natural Sahelian soil inoculated with or without the endomycorrhizal fungus, Glomus intraradices. In control trials, the determinant factor structuring the soil nematode fauna was the plant species, related plants having a similar influence on the nematode community in the soil. Soil nematode abundance increased from exotic acacias (3.3 g-1 dry soil) to native acacias (11.5 g-1 dry soil) and Sesbania species (17.6 g-1 dry soil). Plant feeding nematodes (mainly Scutellonema and Tylenchorhynchus) were significantly less abundant under exotic acacias (1.4 g-1 dry soil) than under native acacias (7.2 g-1 dry soil) or Sesbania species (7.3 g-1 dry soil). Bacterial feeding nematode density increased from exotic acacias (1.2 g-1 dry soil) to native acacias (3.0 g-1 dry soil) and Sesbania species (7.7 g-1 dry soil) as total densities. However, the differences in the structure of the nematode communities between plant groups were suppressed in the presence of the mycorrhizal fungus. In fact, no difference in nematode densities remained between plant groups when G. intraradices developed in several dominant taxa belonging to different trophic groups, particularly: Tylenchorhynchus, Apelenchina, Cephalobus and Dorylaimoidea. This study clearly indicated that inoculation with the arbuscular mycorrhizal fungus G. intraradices diminished the plant-specific effect on the structure of the soil nematode community.  相似文献   

11.
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   

12.
Re-vegetation of fly ash, the principal by-product of coal fired power stations, is hampered by its unfavourable chemical and physical properties for plant growth. In the present study, we evaluated the use of inoculation with a mycorrhiza-associated bacterial strain (Sphingomonas sp. 23L) to promote mycorrhiza formation and plant growth of three willow clones (Salix spp.) on fly ash from an over-burdened dump in a pot experiment. The high pHH2O (8.7) and low nitrogen content (Nt = 0.1 g kg−1) in combination with hydrophobicity of the particle surfaces caused low plant growth. Inoculation of the willows with Sphingomonas sp. 23L improved the nitrogen uptake by plants, increased plant growth and stimulated formation of ectomycorrhizae with an autochthonous Geopora sp. strain on all three willow clones. The ectomycorrhiza formed by the Geopora sp. was morphologically and anatomically described. The inoculation significantly increased the shoot growth of two Salix viminalis clones and the root growth of a S. viminalis x caprea hybrid clone. We conclude that inoculation with mycorrhiza promoting bacterial strains might be a suitable approach to support mycorrhiza formation with autochtonous site-adapted ectomycorrhizal fungi in fly ash and thereby to improve re-vegetation of fly ash landfills with willows.  相似文献   

13.
Laboratory tests and greenhouse experiments were carried out to investigate the abilities of Bacillus subtilis Y-IVI to promote plant growth and to colonize the rhizosphere and interior tissues of muskmelon. Laboratory tests showed that B. subtilis Y-IVI can produce indole acetic acid, siderophores, and ammonia. The inoculation of soil with green fluorescent protein-tagged Y-IVI (GY-IVI) significantly increased plant shoot and root dry weights as compared with the non-inoculated soils. The inoculation of soil with B. subtilis GY-IVI maintained approximately 108 colony-forming units (cfu) of GY-IVI per gram of dry rhizosphere soil for 1 month. The GY-IVI recovered from the interior of crowns and roots in the inoculated soil were 106 and 107 cfu g−1 dry weight, respectively, suggesting that GY-IVI acted as an endophyte. In the present study, we combined the two important growth promotion ingredients, colonization ability and growth promotion metabolites produced by biological agents, to investigate B. subtilis Y-IVI’s promotion effects on muskmelon growth.  相似文献   

14.
A greenhouse experiment was conducted to study the effect of mycorrhizal colonization by Gigaspora margarita, Glomus intraradices, and Acaulospora laevis on nutrient uptake of K, Ca, Mg, Cu, Zn, Fe, and Mn by Astragalus sinicus L. in soils spiked with lanthanum at five rates (0, 1, 5, 10, and 20 mg kg−1). Lanthanum application significantly decreased the concentrations of K, Ca, Mg, Cu, Zn, and Fe in shoots and the concentrations of Cu and Zn in roots. Mycorrhizal treatments markedly improved uptake of nutrients, and these results are important since nutrient deficiency often occurs in contaminated sites.  相似文献   

15.
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   

16.
Cotton Verticillium wilt is a destructive soil-borne disease affecting cotton production. In this study, application of bio-organic fertilizer (BIO) at the beginning of nursery growth and/or at the beginning of transplanting was evaluated for its ability to control Verticillium dahliae Kleb. The most efficient control of cotton Verticillium wilt was achieved when the nursery application of BIO was combined with a second application in transplanted soil, resulting in a wilt disease incidence of only 4.4%, compared with 90.0% in the control. Denaturing gradient gel electrophoresis patterns showed that the consecutive applications of BIO at nursery and transplanting stage resulted in the presence of a unique group of fungi not found in any other treatments. Humicola sp., Metarhizium anisopliae, and Chaetomium sp., which were considered to be beneficial fungi, were found in the BIO treatment, whereas some harmful fungi, such as Alternaria alternate, Coniochaeta velutina, and Chaetothyriales sp. were detected in the control. After the consecutive applications of BIO at nursery and transplanting stage, the V. dahliae population in the rhizosphere soil in the budding period, flowering and boll-forming stage, boll-opening stage, and at harvest time were 8.5 × 102, 3.1 × 102, 4.6 × 102, and 1.7 × 102 colony-forming units per gram of soil (cfu g−1), respectively, which were significantly lower than in the control (6.1 × 103, 3.4 × 103, 5.2 × 103, and 7.0 × 103 cfu g−1, respectively). These results indicate that the suggested application mode of BIO could effectively control cotton Verticillium wilt by significantly changing the fungal community structure and reducing the V. dahliae population in the rhizosphere soil.  相似文献   

17.
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   

18.
Cropping in low fertility soils, especially those poor in N, contributes greatly to the low common bean (Phaseolus vulgaris L.) yield, and therefore the benefits of biological nitrogen fixation must be intensively explored to increase yields at a low cost. Six field experiments were performed in oxisols of Paraná State, southern Brazil, with a high population of indigenous common bean rhizobia, estimated at a minimum of 103 cells g–1 soil. Despite the high population, inoculation allowed an increase in rhizobial population and in nodule occupancy, and further increases were obtained with reinoculation in the following seasons. Thus, considering the treatments inoculated with the most effective strains (H 12, H 20, PRF 81 and CIAT 899), nodule occupancy increased from an average of 28% in the first experiment to 56% after four inoculation procedures. The establishment of the selected strains increased nodulation, N2 fixation rates (evaluated by total N and N-ureide) and on average for the six experiments the strains H 12 and H 20 showed increases of 437 and 465 kg ha–1, respectively,in relation to the indigenous rhizobial population. A synergistic effect between low levels of N fertilizer and inoculation with superior strains was also observed, resulting in yield increases in two other experiments. The soil rhizobial population decreased 1 year after the last cropping, but remained high in the plots that had been inoculated. DGGE analysis of soil extracts showed that the massive inoculation apparently did not affect the composition of the bacterial community.  相似文献   

19.
Abstract

In two pot experiments, cucumber (Cucumis sativus L. cv. Jinlu No. 3) seedlings were each inoculated with one of three arbuscular mycorrhizal fungi (AMF), Glomus mosseae, Glomus intraradices, or Glomus versiforme, or uninoculated. Seedling growth and weight of single fruit were investigated. The results indicated that growth of seedlings was significantly enhanced by G. mosseae, inhibited by G. versiforme, and not significantly influenced by G. intraradices. The dry weight of seedlings inoculated with G. mosseae was 1.2 times its counterparts. The concentrations of nitrogen (N) and phosphorus (P) in roots and magnesium (Mg), copper (Cu), and zinc (Zn) concentration in shoots were increased by inoculating the three AMF, and potassium (K) and iron (Fe) concentrations in shoots decreased significantly. The weights of single fruit of plants preinoculated with G. mosseae and G. versiforme were about 1.4 and 1.3 times higher than those from the uninoculated treatment, respectively.  相似文献   

20.
This study aims to determine leaf litter preference, consumption rate, growth rate, food conversion efficiency, and quality of fecal pellets of two endemic pill millipedes (Arthrosphaera dalyi and Arthrosphaera davisoni) of the Western Ghats of India by laboratory microcosm experiments. Among seven combinations of three plantation leaf litters offered in 4-day trial, top three preferred combinations were selected for 4-week trial. In 4-week trial, preference of mixed litter diet was higher than single litter diet, which resulted in enhanced growth as well as food conversion efficiency of millipedes. Among Hopea , Pongamia , and Areca litters, A. dalyi preferred Hopea + Pongamia, and its consumption was significantly correlated with contents of organic carbon (P < 0.05; r = –0.97) and nitrogen (P < 0.01; r = 0.99), while growth rate with phosphorus content (P < 0.05; r = 0.97) and food conversion efficiency with contents of organic carbon (P < 0.05; r = 0.98) and calcium (P < 0.01; r = –0.99). Among Areca , Elettaria , and Coffea litters, Areca + Elettaria  + Coffea was most preferred by A. davisoni, which was significantly correlated with organic carbon content (P < 0.05; r = 0.98) and food conversion efficiency with calcium content (P < 0.0001; r = 0.99). The food conversion efficiency, however, was the highest in millipedes fed with Areca  +  Elettaria. The present study demonstrated increased nitrogen and phosphorus contents and decreased phenolic content and C/N ratio in fecal pellets of pill millipedes fed with plantation litter, and thus, these millipedes play an important role in leaf litter mineralization and soil enrichment in plantations Western Ghats.  相似文献   

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