Effect of Azospirillum inoculants on arbuscular mycorrhiza establishment in wheat and maize plants (original) (raw)
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Applied Soil Ecology, 2000
Arbuscular mycorrhizal fungi (AMF) and rhizobacteria (Pseudomonas fluorescens) have been targeted for plant growth promotion in order to reduce agrochemical inputs. However, the effects of their interaction on root morphology under different nutrient levels are unknown. Moreover, both soil microorganisms can alter the levels of plant hormonal regulators but no in vivo evidence is available for their interplay with cytokinin (CK) on root morphology. In a full-factorial greenhouse experiment we investigated the effects of interaction between Rhizophagus intraradices, P. fluorescens 8569r, phosphorus (P) amendment and plant CK deficiency on tobacco root morphology, shoot yield and quality. Our results suggest that reduced CK levels may be involved in plant signaling to stimulate AMF hyphal growth in the roots. In addition, we document that a bacteria isolated from the rhizosphere of a non-mycorrhizal plant can function as mycorrhizal helper bacteria, most likely via interplay with phytohormones. The two soil microorganisms, depending on the inoculum combination, P amendment and plant CK levels, modified tobacco root morphology. Our results suggest that the positive interactions between P. fluorescens and AMF depend on soil nutrient status and root hormonal balance. Both microorganism modified shoot yield and these effects seem to result from altered root morphology. Overall, our study support early conclusions that the classification of a soil microorganism as detrimental or beneficial should be based upon their net effects on the plant growth according to circumstances. We suggest this consideration to be extended to the effects of interaction between soil microorganisms on root morphology.
The effect of the co-inoculation of arbuscular mycorrhizal fungi (AMF) and Azospirillum on micro-propagated banana seedlings development during their adaptation phase was determined. At the time of transplanting, banana seedlings were inoculated with an indigenous mycorrhizal inoculum containing 10 spores/g at four doses: 0, 50, 100 and 200 g. Seventy days after fungal inoculation, 20 ml of Azospirillum in four concentrations (0, 10 6 , 10 7 and 10 8 CFU/ml) were applied. Finally, after 98 days from the start of the experiment a second dose (40 ml) of Azospirillum in the concentrations mentioned above was inoculated. Plants were harvested 5 months after transplanting and the growth and nutritional parameters were evaluated. The analysis of the data showed that banana plants co-inoculated with 200 g of AMF and 1.5E 8 CFU/ml of Azospirillum presented greater development, an increase of 7 times in height, 4 times in perimeter, 16 times in leaf area, 12 times in aerial biomass, and 8 times in root biomass relative to control plants. The results achieved were due to synergism between fungus-bacteria when inoculated at higher doses, with lower doses stimulating growth is minimal. The co-inoculation in high doses demonstrates adequate support and cooperative effect between HMA and Azospirillum crops. In addition, co-inoculation promotes optimal nutritional status because microorganisms allowed plants achieve greater absorption of phosphorus and nitrogen relative to those treated with single inoculation and the control.
1986
Inoculation of wheat with Azospirillum brasilense, combined with the application of four fungal and bacterium-inhibiting substances to which A. brasilense is resistant in the soil, decreased the rhizosphere population, while it increased wheat root colonization by A. brasilense, even in cases of poor inoculation. The inoculation significantly increased the following wheat plant parameters as well: plant dry weight, number of tillers per plant, spikelet fertility, harvest index, and grain yield. This model may provide a new approach to improve control of root colonization by beneficial bacteria.
2004
The present investigation was conducted to know the impact of bio-inoculants in low input field conditions on the magnitude and direction of gene effects and mean performance of some morphological and productivity traits in three wheat cultivars WH 147 (medium mineral input), WH 533 (drought tolerant), Raj 3077 (drought tolerant) and six generations namely P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 of three crosses i.e. WH 147 × WH 533, WH 533 × Raj 3077 and WH 147 × Raj 3077. The experiment was conducted in randomised block design with three replications and three treatments i.e. control (C, without inoculation), inoculation with arbuscular mycorrhiza fungi (AMF, Glomus fasciculatum), and AMF + Azotobacter chroococcum (Azc). Mineral fertilizer (80 kg N/ha + 40 kg P/ha + 18 kg ZnSO 4 /ha) was applied in all the three treatments. The application of bio-inoculants, AMF and AMF + Azc had a positive effect on plant height, peduncle length, grain yield, biological yield and harvest index in various populations of all the crosses. However, in some of the generations the impact of bio-inoculants was insignificant. The joint scaling test revealed that additive-dominance gene effects were mainly operative in governing expression of peduncle length, tillers per plant, plant height, grains/spike, grain yield and all traits except days to flowering and harvest index in crosses WH 147 × WH 533 and WH 533 × Raj 3077. The application of bioinoculants influenced gene effects for days to flowering, days to maturity, flag leaf area, spike length, grains/spike, 1000 grain weight and harvest index where complex genetic interactions were changed to simple additive-dominance gene effects in the cross WH 147 × Raj 3077. Likewise, additive-dominance gene effects were altered and digenic interactions exhibited for days to maturity, flag leaf area in WH 147 × WH 533 and days to flowering, plant height, flag leaf area in WH 533 × Raj 3077. Flag leaf area and plant height were governed by additive gene effects while for days to maturity and 1000-grain weight both additive and dominance gene effect were important. Duplicate epistasis was important in all the three crosses for days to flowering and harvest index and in the cross WH 147 × Raj 3077 for grain weight grains per spike and flag leaf area.
Zenodo (CERN European Organization for Nuclear Research), 2022
Indigenous arbuscular mycorrhizae Fungi (AMF) have a potential to boost maize (Zea mays) growth and increase the P and Zn uptake through the symbiotic association they form with the plant, even in acidic soils conditions. Five AMF inoculums produced from the most abundant and ubiquitous morphotypes isolated from field soils in maize fields in South Kivu (DRC) were assessed. A greenhouse experiment was conducted to determine the role of these AMF on nutrients uptake in a Nitisol and a Ferralsol. Eight treatments namely inoculums named AMF1 (Gigaspora gigantea), AMF2 (Gigaspora sp.), AMF3 (Gigaspora margarita), AMF4 (Rhizophagus intraradices) AMF5 (Acaulospora reducta), mineral phosphorus fertilizers (Pi), commercial biofertilizer Rhizatech and a Control were laid in a randomized complete block design. In the Ferralsol, Pi application, Rhizatech and AMF2 produced the highest height. Pi application resulted in the best shoot biomass. No difference was observed for the P content, but for the Zn content, AMF2 was the highest. Roots colonization did not vary among treatments. In the Nitisol, AMF4 produced the highest plant height and AMF1 the highiest chlorophyll content. AMF4 and Rhizatech colonized highly the roots. AMF3 gave the highest P however, Zinc content was equal in all treatments and the controls yielded the lowest results. Spores densities in both inoculums produced and experimental soils were low compared to the commercial inoculum but growth and roots colonisation was influenced by fertilization and soils types. The performance of efficient AMF inoculums of Gipaspora gigantea, Gigaspora sp., Rhizophagus intraradices and Acaulospora reducta applied with high densities spores and multispecies inoculums should be assessed.
Maize is an important cereal crop of India, stands 3 rd in area and production after rice and wheat. Currently, it is cultivated over an area of 8.49 m ha with a production of 21.28 million tonnes. Maize is one of the most important cereal crops in the world agriculture economy both as food for man and feed for animals. It is a miracle crop, having high yield potential, wider adaptability and it is grown throughout the world. Maize is called "Queen of Cereals" because of its productive potential compared to any other cereal crop. In this present study, four AM Fungal spores isolated from five different locations in Cuddalore. The isolated fungal spores are Glomus fasciculatum, Glomus mossae, Gigaspora margarita and Acaulospora laevis. Among the fungal spores, efficient strain selected from Phoaphatase activity, Glomus fasciculatum used for growth of Zea mays by produced the acid phosphatase activity (24.80 µg/ 24 h. 10 g -1 of root) and alkaline phosphatase activity (23.00 µg/ 24 h. 10 g -1 of root) on 90 DAS.
Journal of Plant Physiology, 2011
The response of rice plants to inoculation with an arbuscular mycorrhizal (AM) fungus, Azospirillum brasilense, or combination of both microorganisms, was assayed under well-watered or drought stress conditions. Water deficit treatment was imposed by reducing the amount of water added, but AM plants, with a significantly higher biomass, received the same amount of water as non-AM plants, with a poor biomass. Thus, the water stress treatment was more severe for AM plants than for non-AM plants. The results showed that AM colonization significantly enhanced rice growth under both water conditions, although the greatest rice development was reached in plants dually inoculated under well-watered conditions. Water level did not affect the efficiency of photosystem II, but both AM and A. brasilense inoculations increased this value. AM colonization increased stomatal conductance, particularly when associated with A. brasilense, which enhanced this parameter by 80% under drought conditions and by 35% under well-watered conditions as compared to single AM plants. Exposure of AM rice to drought stress decreased the high levels of glutathione that AM plants exhibited under well-watered conditions, while drought had no effect on the ascorbate content. The decrease of glutathione content in AM plants under drought stress conditions led to enhance lipid peroxidation. On the other hand, inoculation with the AM fungus itself increased ascorbate and proline as protective compounds to cope with the harmful effects of water limitation. Inoculation with A. brasilense also enhanced ascorbate accumulation, reaching a similar level as in AM plants. These results showed that, in spite of the fact that drought stress imposed by AM treatments was considerably more severe than non-AM treatments, rice plants benefited not only from the AM symbiosis but also from A. brasilense root colonization, regardless of the watering level. However, the beneficial effects of A. brasilense on most of the physiological and biochemical traits of rice plants were only clearly visible when the plants were mycorrhized. This microbial consortium was effective for rice plants as an acceptable and ecofriendly technology to improve plant performance and development.