Effect of mycorrhizal inoculation and soil restoration on the growth of Pinus halepensis seedlings in a semiarid soil

An experiment was carried out to evaluate the growth of mycorrhizal Pinus halepensis seedlings planted in a semiarid soil amended with urban refuse in southeast Spain. Three fungal species were used: Pisolithus tinctorius, Rhizopogon roseolus, and Suillus collinitus. After 8 months, inoculated seedlings grown under controlled conditions did not differ significantly from controls with regard to plant height and nutrient assimilation. Other features such as root development and stem dry weight showed that the plants grew better in the absence of mycorrhizal inoculation. The mycorrhizal seedlings and the controls were planted in three experimental plots treated with urban refuse (0, 6, and 12 Kg m^-2). After 1 year of growth under field conditions the results showed that the type of fungus inoculated significantly influenced P. halepensis development. This effect varied with the dose of urban refuse. Plant growth was encouraged by the application of refuse but only at the lowest dose. Under these conditions P. tinctorius was the most effective fungus and R. roseolus yielded poorer plant development. The highest application of urban refuse led to notably worse results and a significant decrease in seedling growth compared to controls. In the control plot (without refuse) S. collinitus was the most effective fungus in plant growth improvement. The smallest application of urban refuse had a positive effect on the assimilation of N, P, and K in seedlings inoculated with P. tinctorius and S. collinitus.     

Interactions between the arbuscular mycorrhizal fungus Glomus mosseae and plant growth-promoting fungi and their significance for enhancing plant growth and suppressing damping-off of cucumber (Cucumis sativus L.)

This study investigated the interactions between the arbuscular mycorrhizal fungus (AMF) Glomus mosseae and the plant growth-promoting fungi (PGPF) Penicillium simplicissimum GP17-2 and Trichoderma harzianum GT3-2 in relation to their colonization of roots and the rhizosphere of cucumber (Cucumis sativus L.), and their effect on plant growth and suppression of the damping-off pathogen Rhizoctonia solani. Combined inoculation of T. harzianum with G. mosseae increased the percentage of AMF root colonization, but the presence of P. simplicissimum had no significant effect on mycorrhizal formation. The existence of G. mosseae decreased the population development of T. harzianum in and/or around the roots, however, growth of P. simplicissimum was not affected. Both PGPF isolates were effective in increasing the plant shoot and root dry weight, G. mosseae, however, was not. Nevertheless, co-inoculation of G. mosseae with T. harzianum synergistically enhanced plant growth. A comparable additive effect on plant growth was not observed when P. simplicissimum was combined with G. mosseae. Treating plants with the PGPF either simultaneously with the pathogen or prior to pathogen infection suppressed damping-off disease. G. mosseae was significantly effective in reducing disease severity when inoculated prior to the pathogen but not when inoculated simultaneously with the pathogen. Interestingly, the levels of disease protection achieved by the single inoculation of P. simplicissimum, T. harzianum or G. mosseae were significantly increased by combined inoculation of each PGPF with G. mosseae.     

Dual inoculation of pretransplant stage Oryza sativa L. plants with indigenous vesicular-arbuscular mycorrhizal fungi and fluorescent Pseudomonas spp.

Summary This study examined the response of rice (Oryza sativa L.) plants at the pretransplant/nursery stage to inoculation with vesicular-arbuscular mycorrhizal (VAM) fungi and fluorescent Pseudomonas spp., singly or in combination. The VAM fungi and fluorescent Pseudomonas spp. were isolated from the rhizosphere of rice plants. In the plants grown in soil inoculated with fluorescent Pseudomonas spp. alone, I found increases in shoot growth, and in root length and fine roots, and decreases in root growth, and P and N concentrations. In contrast, in the plants colonized by VAM fungi alone, the results were the reverse of those of the pseudomonad treatment. Dual inoculation of soil with VAM fungi and fluorescent Pseudomonas spp. yielded plants with the highest biomass and nutrient acquisition. In contrast, the plants of the control treatment had the lowest biomass and nutrient levels. The dual-inoculated plants had intermediate root and specific root lengths. The precentages of mycorrhizal colonization and colonized root lengths were significantly lower in the dual-inoculated treatment than the VAM fungal treatment. Inoculation of plants with fluorescent Pseudomonas spp. suppressed VAM fungal colonization and apparently reduced photosynthate loss to the mycorrhizal associates, which led to greater biomass and nutrient levels in dual-inoculated plants compared with plants inoculated with VAM fungi alone. Dual inoculation of seedlings with fluorescent Pseudomonas spp. and VAM fungi may be preferable to inoculation with VAM alone and may contribute to the successful establishment of these plants in the field.     

Boron fertilization,vesicular‐arbuscular mycorrhizal colonization and growth of citrus jambhiri lush

The role of boron (B) fertilization in the vesicular‐arbuscular mycorrhizal (VAM) colonization and growth of container‐grown Citrus seedlings was evaluated. Citrus jambhiri Lush, seedlings inoculated with Glomus fasciculatum, Glomus etunicatum or non‐inoculated were grown in a sandy loam soil for sixteen weeks. Seedlings were fertilized with 25 ug/ml B applied to the foliage as a mist, to the soil as a solution, or to both the foliage and the soil. Boron applied to the foliage or to the soil significantly increased root exudation of reducing sugars and amino acids two weeks after seedling germination. Subsequently, foliar fertilization with B significantly increased VAH colonization of seedlings relative to the controls. Plants inoculated with G. fasciculatum were larger and had greater VAM development than those inoculated with G. etunicatum. The growth of the noninoculated seedlings was not enhanced by B fertilization. The superior VAH colonization and growth of inoculated seedlings fertilized with B suggests that B stimulates the efficacy of plant fungi symbiosis.     

Protecting Cucumber from Fusarium Wilt with Arbuscular Mycorrhizal Fungi

A pot experiment was conducted to investigate the biocontrol effects of arbuscular mycorrhizal fungi (AMF) Glomus mosseae and Glomus versiforme on Fusarium oxysporum wilt disease of cucumber (Cucumis sativus L.). The results indicated that both AMF improved the growth of cucumber seedlings and reduced disease severity, but G. versiforme was more efficient. Compared with nonmycorrhizal plants infected by F. oxysporum, shoots and roots dry weights increased by 100% and 80% in G. versiforme–inoculated plants, and the qualities of seedlings were significantly improved; meanwhile, nitrogen, phosphorus, and potassium contents in shoots of G. versiforme–inoculated plants were significantly greater than those of G. mosseae–inoculated plants and nonmycorrhizal plants. Moreover, for mycorrhizal plants, soluble sugar and free proline contents in mycorrhizal roots were significantly greater than those of nonmycorrhizal treatment; however, malonaldehyde content in roots and the quantity of fungi in rhizosphere decreased when the plants were attacked by F. oxysporum.     

Control of Fusarium Wilt of Cucumber Seedlings by Inoculation with an Arbuscular Mycorrhical Fungus

A glasshouse pot experiment was conducted to investigate the impact of inoculation of cucumber at the germination stage with Glomus etunicatum BEG168 on plant yield and incidence of Fusarium oxysporum f.sp. cucumerinum inoculated 28 days after the start of the experiment. Inoculation with the AM fungus decreased both disease incidence and disease index. Mycorrhizal inoculation also increased P concentrations in the cucumber seedlings. The mycorrhizal seedlings had higher concentrations of proline and polyphenol oxidase activity but lower malondialdehyde than non-mycorrhizal seedlings, indicating that AM inoculation may have protected membrane permeability and reduced the extent of the damage caused by F. oxysporum. The results indicate that the mycorrhizal fungus may influence plant secondary metabolites and increase resistance to wilt disease in cucumber seedlings and may therefore have some potential as a biological control agent.     

RHIZOSPHERIC EFFECT OF VESICULAR ARBUSCULAR MYCORRHIZAL INOCULATION ON BIOMASS PRODUCTION OF RUTA GRAVEOLENS L.: A POTENTIAL MEDICINAL AND AROMATIC HERB

A bio-inoculation experiment was performed on Ruta graveolens L., known as “Garden Rue” seedlings for the biomass production. Seedlings were inoculated with single and in combined mycorrhizal treatments. All inoculated seedlings showed significant biomass production than control seedlings. The phosphorus (P) content was more in seedlings inoculated with consortium of three native VAM fungi followed by Glomus mosseae, Acaulospora laevis and Gigaspora gigantea alone treatments. The control seedlings had the least P content but root P content was more than shoot P content in all treatments. The biomass of shoot and root was also significantly more in seedlings inoculated with consortium followed by G. mosseae, A. laevis and G. gigantea alone treatment. The control seedlings again had low shoot and root biomass. The Biovolume index (B_i) was also high in all inoculated treatments than non-inoculated control but consortium treatment (7.98) had at par B_i than rest of inoculation treatments. The quality index (Q_i) value was also high in mixed consortium (1.42) and A. laevis treatment (1.42) each respectively than G. mosseae (1.38) and G. gigantea (1.29) treatments. Control seedlings had low value of Q_i (1.27). The present study indicates that G. mosseae, A. laevis, G. gigantea are the best strains of VAM symbionts when mixed together for inoculating the R. graveolens to get higher yield of biomass. A. laevis is also good strain of VAM fungi for the same purpose. The G. gigantea alone proved least effective strain for inoculation purpose in R. graveolens but when mixed together in consortium of native VAM fungi as described above executed good results for enhancing the biomass production.     

AM fungi inoculation and addition of microbially‐treated dry olive cake‐enhanced afforestation of a desertified Mediterranean site

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.     

Growth Response and Nutrient Uptake of Eriobotrya japonica Plants Inoculated with Three Isolates of Arbuscular Mycorrhizal Fungi Under Water Stress Condition

Mycorrhizal technique is a promising biotechnology in horticultural industry, benefiting plants exposed to diverse abiotic stresses. In this study, the effects of three arbuscular mycorrhizal fungi (AMF), Acaulospora laevis, Glomus mosseae, and Glomus caledonium on plant growth and nutrient uptake of loquat (Eriobotrya japonica Lindl.) seedlings under three water regimes (well watered, water stressed-slight, water stressed-heavy) were investigated. Results showed that inoculated seedlings had higher dry biomass, plant height, and total leaf areas than those un-inoculated ones. AMF effect was the greatest for water stressed-heavy seedlings, followed by water stressed-slight seedlings and well watered seedlings. All AMF species increased the uptake of nitrogen (N) potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), and the mycorrhizal contributions to the nutrient uptake were positively related to that to the biomass. Data suggest that AMF inoculation increases the tolerance of loquat seedlings to drought stress, and the improved nutrient uptake by AMF contributes greatly to the tolerance.     

Responses of directly seeded wetland rice to arbuscular mycorrhizal fungi inoculation

The mycorrhizal enhancement of plant growth is generally attributed to increased nutrients uptake. A greenhouse experiment was conducted to investigate the effect of arbuscular mycorrhizal fungi (AMF) inoculation on the growth and nutrient uptake of directly seeded wetland rice. Seeds were germinated and inoculated with arbuscular mycorrhizal fungi or left uninoculated. The plants were grown at 60% of ‐0.03 MPa to establish the mycorrhizas. After 5 weeks, half of the pots were harvested and the rest were flooded with deionized water to maintain 3–5 cm of standing water until harvesting (122 days after sowing). Mycorrhizal fungal colonization of rice roots was 36.2% at harvest. Mycorrhizal fungi inoculated rice seedlings grew better compared to uninoculated seedlings and had increased grain yield (10%) at the harvesting stage. Shoot and root growth were effectively increased by AMF inoculation at the harvesting stage. The nitrogen (N) and phosphorus (P) acquisition of direct seeding wetland rice were significantly increased by AMF inoculation. The AMF enhanced N and P translocation through the hyphae from soils to roots/shoots to grains effectively.     

Under filed conditions,mycorrhizal inoculum effectiveness depends on plant species and phosphorus nutrition

Abstract

The cultivation of horticultural crops, such as green peppers, tomatoes, eggplants and bell peppers is very common in semi-arid Mediterranean climate conditions. Two field experiments were performed to determine the effect of mycorrhizal species, plant species and phosphorus levels on mycorrhizal effectiveness and phosphorus (P) and zinc (Zn) nutrient uptake. In the first experiment, under field conditions, four plants species were inoculated with five arbuscular mycorrhizae (AM) species. In the second field experiment, under the same soil conditions, the same plant species were treated with three levels of phosphorus (P), i.e., control; 50?kg and 100?kg P₂O₅ ha^?1. The most effective mycorrhiza species Claroideoglomus etunicatum selected in the first experiment was used in the second field first experiment. In the first experiment, fruit yield enhancement, yield increase, inoculation effectiveness and nutrient concentration in the plant leaves were analyzed. Under field conditions, plant species growth is strongly dependent on the species of AM fungi. Tomato and green pepper plants were inoculated with Cl. etunicatum, eggplants were inoculated with Funneliformis mosseae and bell peppers were inoculated with Rhizophagus clarus, which are high fruit-yielding plant species. In general, Fu. mosseae and Cl. etunicatum increased the yield of the tomatoes, green peppers and eggplants. It seems mycorrhiza species specific to plant species. In the second experiment, mycorrhizal inoculation with P fertilizer application, in particular a moderate amount of P (50?kg ha^?1 P₂O₅) fertilizer increased the green pepper, bell pepper and tomato fruit yield compared with non-inoculated plants and non-P fertilizer application treatments. Increasing the application of P level reduced the mycorrhizal inoculation effectiveness (MIE). The results indicate that for all four solanaceae family plants 50?kg ha^?1 P₂O₅ is a P level threshold for mycorrhizal development, which enhanced plant growth and addition of fertilizer over 50?kg ha^?1 P₂O₅ reduced MIE. P and Zn uptake were significantly increased with mycorrhizal inoculation. These findings are supported by our hypothesis that mycorrhiza inoculation can reduce mycorrhizal dependent horticultural plants P fertilizer requirement.     

AM真菌对田间山银花生长、矿质营养及绿原酸含量的影响

Lonicera confusa, a traditional Chinese medicine herb for treating cold, flu, acute fever, and so forth, is often grown artificially in acidic soils and suffers from phosphorus (P) deficiency. A five-year field experiment was carried out to study the colonization rate, growth, nutrition, and chlorogenic acid content of Lonicera confusa seedlings inoculated with arbuscular mycorrhizal (AM) fungi, Glomus etunicatum and Glomus intraradices. Before transplanting into a field, both AM-inoculated and uninoculated control plants were cultured in nursery beds. In the plants inoculated with the AM fungi, the colonization rate decreased linearly with time and a greater decrease was observed in the plants inoculated with G. intraradices than with G. etunicatum, while the AM colonization increased from 0% to 12.1% in the uninoculated control plants 5 years after transplanting. Plant height, crown diameter, number of new branches, and flower yield increased significantly by AM inoculation as compared to the uninoculated control. Phosphorus concentrations in leaves and flowers increased, and plant uptake of nutrients, e.g., nitrogen (N), P, and potassium (K), was also enhanced significantly by AM inoculation. The Lonicera confusa seedlings had a better response to inoculation of G. intraradices than G. etunicatum in both growth and chlorogenic acid content in flowers. In contrast, both plant P uptake and P concentrations in leaves and flowers were similar between two fungal inoculations. The positive responses of Lonicera confusa to AM inoculation in growth, nutrient uptake, flowering, and chlorogenic acid content in flowers suggested that AM inoculation in nursery beds could promote the plant growth and increase chlorogenic acid content in flowers of Lonicera confusa when grown on acidic and P-deficient soils.     

Effect of simulated acid rain on mycorrhizal infection of Pinus strobus L.

Mycorrhizal infection but not growth of white pine seedlings was reduced by application of simulated rain at pH 3.5 at 3 times ambient rates to plants grown in steamed Mardin soil inoculated with Pisolithus tinctorius. In unsteamed Mardin soil, the simulated acid rain at 3 times ambient rates had no effect on mycorrhizal infection or growth of pine seedlings if the rain was applied to the plants and soil or to only the soil before planting, except that nitrate-containing acid rain increased growth, infection and N content. In limed Mardin soil, the simulated acid rain reduced mycorrhizal infection if applied to the plants and soil as the seedlings were growing but not if applied to the soil before planting. Application of pH 3.5 rain at ambient rates had no detectable influence on mycorrhizal infection in 6 of 9 soils tested, but it stimulated infestion in 3 soils if the simulated rain contained only sulfate and in 1 soil if it had both sulfate and nitrate.     

Interactions of Glomus clarum with Acetobacter diazotrophicus in infection of sweet potato (Ipomoea batatas), sugarcane (Saccharum spp.), and sweet sorghum (Sorghum vulgare)

Summary Spores of the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus clarum obtained from sweet potatoes grown in soil inoculated with this fungus and with an enrichment culture of Acetobacter diazotrophicus contained A. diazotrophicus and several other bacteria, including a diazotrophic Klebsiella sp. Inoculation of micropropagated sweet potatoes with G. clarum and A. diazotrophicus enhanced spore formation in soil compared to VAM inoculation alone. Plants inoculated with VAM spores containing the bacteria showed additional increases in the number of spores formed within roots. A. diazotrophicus infected aerial plant parts only when inoculated together with VAM or when present within VAM spores. Micropropagated sugarcane seedlings inoculated with the same VAM spores containing the diazotrophs also contained much higher numbers of A. diazotrophicus in aerial parts than seedlings inoculated in vitro with the bacteria alone. When grown in non-sterile soil, the sugarcane seedlings again showed the greatest infection of aerial parts after inoculation with VAM spores containing the diazotrophs. This treatment also increased VAM colonization and the numbers of spores formed within roots. Similar effects were observed in sweet sorghum except that the aerial plant parts were not infected by A. diazotrophicus.     

Arbuscular mycorrhizal fungus and rhizobacteria affect the physiology and performance of Sulla coronaria plants subjected to salt stress by mitigation of ionic imbalance

Salt stress has become a major menace to plant growth and productivity. The main goal of this study was to investigate the effect of inoculation with the arbuscular mycorrhizal fungi (AMF; Rhizophagus intraradices) in combination or not with plant growth‐promoting rhizobacteria (PGPR; Pseudomonas sp. (Ps) and Bacillus subtilis) on the establishment and growth of Sulla coronaria plants under saline conditions. Pot experiments were conducted in a greenhouse and S. coronaria seedlings were stressed with NaCl (100 mM) for 4 weeks. Plant biomass, mineral nutrition of shoots and activities of rhizosphere soil enzymes were assessed. Salt stress significantly reduced plant growth while increasing sodium accumulation and electrolyte leakage from leaves. However, inoculation with AMF, whether alone or combined with the PGPR Pseudomonas sp. alleviated the salt‐induced reduction of dry weight. Inoculation with only AMF increased shoot nutrient concentrations resulting in higher K⁺: Na⁺, Ca²⁺: Na⁺, and Ca²⁺: Mg²⁺ ratios compared to the non‐inoculated plants under saline conditions. The co‐inoculation with AMF and Pseudomonas sp. under saline conditions lowered shoot sodium accumulation, electrolyte leakage and malondialdehyde (MDA) levels compared to non‐inoculated plants and plants inoculated only with AMF. The findings strongly suggest that inoculation with AMF alone or co‐inoculation with AMF and Pseudomonas sp. can alleviate salt stress of plants likely through mitigation of NaCl‐induced ionic imbalance, thereby improving the nutrient profile.     

Effect of mixing soil saprophytic fungi with organic residues on the response of Solanum lycopersicum to arbuscular mycorrhizal fungi

The effect of the dual inoculation with arbuscular mycorrhizal (AM) and saprophytic fungi and a combination of wheat straw and sewage sludge residues were studied by determining their effect on dry weight of tomato and on chemical and biochemical properties of soil. Incubation of organic residue (sewage sludge combined with wheat straw) with saprophytic fungi and plant inoculation with mycorrhizal fungi was essential to study plant growth promotion. Soil application of organic residues increased the dry weight of tomato inoculated with Rhizophagus irregularis. The greatest shoot dry mass was obtained when the organic residues were incubated with Trichoderma harzianum and applied to AM plants. However, the greatest percentage of root length colonized with AM in the presence of the organic residues was obtained with inoculation with Coriolopsis rigida. The relative chlorophyll was greatest in mycorrhizal plants regardless of the presence of either saprophytic fungus. The presence of the saprophytic fungi increased soil pH as the incubation time increased. Soil nitrogen and phosphorus contents and acid phosphatase were stimulated by the addition of organic residues, and contents of N and P. Total N and P content in soil increased when the organic residue was incubated with saprobe fungi, but this effect decreased as the incubation period of the residue with saprobe fungi increased. The same trend was observed for soil β‐glucosidase and fluorescein diacetate activities. The application of organic residues in the presence of AM and saprophytic fungi seems to be an interesting option as a biofertilizer to improve plant growth and biochemical parameters of soils.     

Response of Sauropus androgynus to soil phosphorus concentration and mycorrhizal colonization

Thirty three‐day‐old seedlings of nonmycorrhizal Sauropus androgynus were transplanted into pots containing a subsurface Oxisol uninoculated or inoculated with Glomus aggregation at three target soil solution phosphorus (P) concentrations. While no evidence of vesicular‐arbuscular mycorrhizal fungal (VAMF) colonization was noticed in the uninoculated soil, sauropus roots were colonized to the extent of 54%, 60% and 38% in the inoculated soil if target soil P concentrations were 0.014, 0.02 and 0.2 mg/L. VAMF colonization led to significant increases in tissue P and shoot dry matter accumulation at the first two soil P concentrations but not at the highest concentration. Root dry matter yield of mycorrhizal sauropus was greater than that of nonmycorrhizal sauropus at all soil P concentrations tested. Although mycorrhizal inoculation effects at soil P concentrations of 0.014 and 0.02 mg/L were comparable, growth of mycorrhizal plants was greater at the latter P concentration than at the former. Growth of mycorrhizal sauropus at this P concentration was also comparable to non‐mycorrhizal growth of the plant at soil P concentration of 0.2 mg/L. Based on the growth responses observed sauropus was classified as a highly mycorrhizal dependent species.     

Effect of peat on mycorrhizal colonization and effectiveness of the arbuscular mycorrhizal fungus Gigaspora margarita

Abstract

The influence of the addition of Chinese peat and Canadian peat on arbuscular mycorrhizal colonization, mycorrhizal effectiveness and host-plant growth was investigated in a pot experiment. Chinese peat or Canadian peat was mixed with Masa soil (weathered granite soil) at different levels (0, 25, 50, 100, 150 or 200 g kg^?1) into which an arbuscular mycorrhizal fungus (AMF) Gigaspora margarita Becker & Hall was inoculated, and seedlings of Miscanthus sinensis Anderess were planted. There was a significant increase in plant growth with increasing amounts of Chinese peat. The growth-promoting effect of the AMF on the host was enhanced when the addition of Chinese peat was increased from 25 to 100 g kg^?1. Root colonization and the number of spores proliferating increased with increases at low levels of Chinese peat (from 25 to 100 g kg^?1), and decreased gradually with higher Chinese peat increments. Although plant growth and root colonization with the addition of Canadian peat increased slightly, Canadian peat suppressed mycorrhizal effectiveness. In contrast to Canadian peat, the addition of Chinese peat improved considerably the physical and chemical properties of the soil, which might result in the promotion of AM formation and mycorrhizal effectiveness.     

Influence of arbuscular mycorrhizal fungi and salinity on growth,biomass, and mineral nutrition of<Emphasis Type="Italic"> Acacia auriculiformis</Emphasis>

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.     

丛枝菌根对三叶草根际磷酸酶活性的影响

以三叶草为材料,利用三室隔网培养方法,探讨了取自肥料长期定位试验中多年施用与不施用有机肥的田间小区土壤上,接种菌根菌（G.mosseae）对根际土壤酸性和碱性磷酸酶活性的影响。植物生长9周后,收获测定菌丝生长室土壤酸性磷酸酶和碱性磷酸酶活性,并对磷酸酶产生位点进行细胞化学定位。结果表明,接种丛技菌根菌对根际土壤酸性和碱性磷酸酶活性均有增强作用,但作用程度在有机服小区土壤上要大于无机肥小区土壤。根际土壤酸性磷酸酶原位化学定位结果表明,菌丝周围有明显的酸性磷酸酶的反应产物,说明报外丛枝菌根菌丝能直接向外分泌磷酸酶。