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Root Infection (root + infection)
Selected AbstractsRelationship between presence of basidiomes, above-ground symptoms and root infection by Collybia fusipes in oaksFOREST PATHOLOGY, Issue 1 2000B. Marçis Summary Collybia fusipes is a common cause of root rot on oak in the north of France. Collybia fusipes basidiomes can be as frequent on oaks in stands where no decline of the trees occurs compared with stands where the decline is chronic. This might be explained by differences in the amount of roots damaged by the parasite. To test that hypothesis, 430 oak trees, Quercus petraea, Quercus robur and Quercus rubra, located in six forests were selected. Half of them showed C. fusipes basidiomes at the trunk base. The association between presence of basidiomes and decline of affected trees depended on the forest. The level of infection of each tree by C. fusipes, as well as the crown appearance, the tree height : diameter at breast height ratio, age and sapwood width were determined. The presence of C. fusipes basidiomes was always associated with significant root infections. The crowns of the trees deteriorated with increasing level of root infection and the decline was severe only when the root damage was heavy. Although the decline of trees that were heavily damaged by C. fusipes was severe in some of the stands, in others, it was only mild, and so the differences in tree decline between the stands could not be attributed solely to differences in root infection severity. Trees damaged by C. fusipes seemed not to be subjected to more competition than their undamaged neighbour as reflected by a similar tree height: diameter at breast height ratio. [source] Plant and fungal identity determines pathogen protection of plant roots by arbuscular mycorrhizasJOURNAL OF ECOLOGY, Issue 6 2009Benjamin A. Sikes Summary 1.,A major benefit of the mycorrhizal symbiosis is that it can protect plants from below-ground enemies, such as pathogens. Previous studies have indicated that plant identity (particularly plants that differ in root system architecture) or fungal identity (fungi from different families within the Glomeromycota) can determine the degree of protection from infection by pathogens. Here, we test the combined effects of plant and fungal identity to assess if there is a strong interaction between these two factors. 2.,We paired one of two plants (Setaria glauca, a plant with a finely branched root system and Allium cepa, which has a simple root system) with one of six different fungal species from two families within the Glomeromycota. We assessed the degree to which plant identity, fungal identity and their interaction determined infection by Fusarium oxysporum, a common plant pathogen. 3.,Our results show that the interaction between plant and fungal identity can be an important determinant of root infection by the pathogen. Infection by Fusarium was less severe in Allium (simple root system) or when Setaria (complex root system) was associated with a fungus from the family Glomeraceae. We also detected significant plant growth responses to the treatments; the fine-rooted Setaria benefited more from associating with a member of the family Glomeraceae, while Allium benefited more from associating with a member of the family Gigasporaceae. 4.,Synthesis. This study supports previous claims that plants with complex root systems are more susceptible to infection by pathogens, and that the arbuscular mycorrhizal symbiosis can reduce infection in such plants , provided that the plant is colonized by a mycorrhizal fungus that can offer protection, such as the isolates of Glomus used here. [source] Comparative effect of biofertilizers on fodder production and quality in guinea grass (Panicum maximum Jacq.)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2008Seema Mishra Abstract BACKGROUND:Panicum maximum Jacq. is one of the most important fodder grasses of the tropics. For good production and growth it requires high amounts of N fertilizer. Chemical fertilizers have a deleterious effect on soil fertility and are not economical for resource-poor farmers. Utilization of plant growth-promoting bacteria and fungi proved to be beneficial for improving crop production as well as the soil fertility. In the present paper the effect of inoculation of N fixer (Azospirillum brasilense) and P solubilizers (arbuscular mycorrhizal (AM) fungi consortia and inoculum of Glomus intraradiaces) was studied in single as well as mixed inoculation on forage yield and quality in guinea grass (Panicum maximum Jacq.) at different cuttings under the cut-and-carry system. RESULTS: Overall five cuttings were obtained during the year. Dual inoculation, i.e., Azospirillum with indigenous AM consortia, significantly improved fodder growth, production and quality in terms of crude protein (CP) content, while neutral detergent fiber (NDF) and acid detergent fiber (ADF) content decreased after this treatment. The density of soil microbes (number of Azospirillum colony-forming units, number of AM spores) was enhanced in mixed inoculation. Chemical fertilizer improved fodder production and CP content significantly over control but also enhanced NDF and ADF content and suppressed the Azospirillum colony-forming units, AM spores and AM root infection. CONCLUSION: It could be concluded from the present study that inoculated N fixer and P solubilizer have a synergistic effect which enhanced overall fodder production, quality and also beneficial microflora in the rhizosphere soil, which also demonstrated the sustainability of biofertilizers. 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