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- Seed coating with arbuscular mycorrhizal fungi as an ecotechnologicalapproach for sustainable agricultural production of common wheat (Triticum aestivumL.)Publication . Oliveira, Rui S.; Rocha, Inês; Ma, Ying; Vosátka, Miroslav; Freitas, HelenaThe exploitation of arbuscular mycorrhizal (AM) fungi has become of great interest in agriculture due to their potential roles in reducing the need for agrochemicals, while improving plant growth and nutrition. Nevertheless, the application of AM fungi by dispersing inocula in granular form to open agricultural fields is not feasible because nontargeted spreading of inocula over large surface areas results in high cost per plant. Seed coating has the potential to significantly reduce the amount of inoculum needed, resulting in cost reduction and increased efficiency. The aim of this study was to assess whether seed coating with AM fungal inoculum is a feasible delivery system for production of common wheat (Triticum aestivum L.). Wheat seeds were coated with inoculum of Rhizophagus irregularis BEG140 and grown under different fertilization conditions: (1) none, (2) partial, or (3) complete. Data indicated that mycorrhizal inoculation via seed coating significantly increased the dry weight of shoot and seed spikes of wheat associated with reduced fertilization. Assessment of nutritional status of wheat showed that plants inoculated with R. irregularis via seed coating displayed enhanced stem concentrations of potassium (K), sulfur (S), and zinc (Zn). There were no significant differences in root colonization between plants conventionally inoculated with R. irregularis in soil and those inoculated via seed coating. Seed coating with AM fungi may be as effective as conventional soil inoculation and may contribute to reduce the utilization of chemical fertilizers. The application of AM via seed coating is proposed as an ecotechnological approach for sustainable agricultural wheat production.
- Arbuscular mycorrhizal fungi are an alternative to the application of chemical fertilizer in the production of the medicinal and aromatic plant Coriandrum Sativum LPublication . Oliveira, Rui S.; Ma, Ying; Rocha, Inês; Carvalho, Maria F.; Vosátka, Miroslav; Freitas, HelenaThe widespread use of agrochemicals is detrimental to the environment and may exert harmful effects on human health. The consumer demand for organic food plants has been increasing. There is thus a rising need for alternatives to agrochemicals that can foster sustainable plant production. The aim of this study was to evaluate the potential use of an arbuscular mycorrhizal (AM) fungus as an alternative to application of chemical fertilizer for improving growth performance of the medicinal and aromatic plant Coriandrum sativum. Plants were inoculated with the AM fungus Rhizophagus irregularis BEG163 and/or supplemented with a commercial chemical fertilizer (Plant Marvel, Nutriculture Bent Special) in agricultural soil. Plant growth, nutrition, and development of AM fungus were assessed. Plants inoculated with R. irregularis and those supplemented with chemical fertilizer displayed significantly improved growth performances when compared with controls. There were no significant differences in total fresh weight between plants inoculated with R. irregularis or those supplemented with chemical fertilizer. Leaf chlorophyll a + b (82%), shoot nitrogen (44%), phosphorus (254%), and potassium (27%) concentrations increased in plants inoculated with R. irregularis compared to controls. Application of chemical fertilizer inhibited root mycorrhizal colonization and the length of the extraradical mycelium of R. irregularis. Inoculation with R. irregularis was equally or more efficient than application of chemical fertilizer in promoting growth and nutrition of C. sativum. AM fungi may thus contribute to improve biologically based production of food plants and reduce the dependence on agrochemicals in agriculture.
- Management of nursery practices for efficient ectomycorrhizal fungi application in the production of Quercus ilexPublication . Oliveira, Rui S.; Franco, Albina R.; Vosátka, Miroslav; Castro, Paula M. L.The application of ectomycorrhizal (ECM) fungi on forest nursery production is regarded as part of good management practice. However, before employing large scale inoculations in a nursery the interaction between ECM symbionts, growth substrate and fertilisation input should be studied to select the most suitable nursery practices for promoting plant growth and ECM colonisation. In this study, seedlings of Quercus ilex were inoculated with Paxillus involutus, Hebeloma mesophaeum or Cenococcum geophilum and grown in three different substrates commonly used in forest nurseries: peat-based compost, forest soil or composted pine bark. The effect of various fertilisation regimes was also studied. The choice of substrate had a significant effect on plant growth and ECM colonisation. The most appropriate combination of substrate and ECM fungus for Q. ilex growth and nutrition was peat and H. mesophaeum. Plants grown on a peat-based compost and inoculated with H. mesophaeum had a significantly greater biomass and leaf phosphorus concentration without fertilisation. Composted pine bark was found not to be suitable for growth or for mycorrhization. If the appropriate growth substrate is selected, it is possible to replace the use of chemical fertilisers by inoculation with selected ECM fungi. This results in a significant increase in plant development, and thus ECM fungi can be recommended as a more environmental friendly biotechnological approach to plant management in the nursery.
- Genetic, phenotypic and functional variation within a Glomus geosporum isolate cultivated with or without the stress of a highly alkaline anthropogenic sedimentPublication . Oliveira, Rui S.; Boyer, Louisa Robinson; Carvalho, Maria F.; Jeffries, Peter; Castro, Paula M.L.; Vosátka, Miroslav; Dodd, John C.Genetic, phenotypic and functional variation in a Glomus geosporum isolate obtained from a highly alkaline anthropogenic sediment was investigated. Two cultivation lineages of G. geosporum (BEG199 and BEG211) were created by sub-culturing with or without the stress of the sediment. Genetic variation was assessed on spores from both cultivation lineages in the large sub-unit rRNA gene D2 region using PCR-single strand conformational polymorphism (PCR-SSCP) and sequencing. Phenotypical and functional variation of the cultivation lineages were assessed after inoculation onto Conyza bilbaoana. The sequence diversity obtained in G. geosporum BEG211 was significantly different from that obtained in G. geosporum BEG199. Glomus geosporum BEG199 was more effective than G. geosporum BEG211 in promoting the growth of C. bilbaoana in inert substrate and in increasing its leaf phosphorus concentration when the plant was grown in sediment. After inoculation onto C. bilbaoana, G. geosporum BEG199 colonised the roots to a greater extent, produced a significantly larger number of spores and presented a greater length of extraradical mycelium than G. geosporum BEG211. The results indicate that environmental conditions under which arbuscular mycorrhizal fungi (AMF) are cultivated can influence their effects in host plants. Also, AMF might quickly lose gained-tolerance to environmental stresses when maintained without the selective pressure of those stresses. This study has implications for the production of commercial inoculum of AMF and for the maintenance of AMF cultures. The results indicate that inoculum of AMF should be produced and AMF cultures should be maintained in substrates or media containing the original edaphic stresses.