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Inoculum of arbuscular mycorrhizal fungi, with growing use in horticulture, is produced mainly in two technically different cultivation systems: in vivo culture in symbiosis with living host plants or in vitro culture in which the fungus life cycle develops in association with transformed roots. To evaluate the effectiveness and the infectivity of a defined isolate obtained by both production methods, a replicated comparative evaluation experiment was designed using different propagules of Rhizophagus irregularis produced in vivo on leek plants or in vitro in monoxenic culture on transformed carrot roots. The size of the spores obtained under both cultivation methods was first assessed and bulk inoculum, spores, sievings, and mycorrhizal root fragments were used to inoculate leek plantlets. Spores produced in vitro were significantly smaller than those produced in vivo. Although all mycorrhizal propagules used as a source of inoculum were able to colonize plants, in all cases, leek plants inoculated with propagules obtained in vivo achieved significantly higher mycorrhizal colonization rates than plants inoculated with in vitro inocula. Inoculation with in vivo bulk inoculum and in vivo mycorrhizal root fragments were the only treatments increasing plant growth. These results indicate that the production system of arbuscular mycorrhizal fungi itself can have implications in the stimulation of plant growth and in experimental results. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rosemary forms an arbuscular mycorrhizal (AM) symbiosis with a group of soilborne fungi belonging to the phylum Glomeromycota, which can modify the plant metabolome responsible for the antioxidant capacity and other health beneficial properties of rosemary. RESULTS: The effect of inoculating rosemary plants with an AM fungus on their growth via their polyphenolic fingerprinting was evaluated after analyzing leaf extracts from non‐inoculated and inoculated rosemary plants by ultra‐high performance liquid chromatography‐high resolution mass spectrometry (UHPLC‐HRMS). Plant growth parameters indicated that mycorrhizal inoculation significantly increased plant height and biomass. Chemical modifications in the plant polyphenolic profile distribution were found after a principal components analysis (PCA) loading plots study. Four compounds hosting strong antioxidant properties – ferulic acid, asiatic acid, carnosol, and vanillin – were related to mycorrhizal rosemary plants while caffeic and chlorogenic acids had a higher influence on non‐mycorrhizal plants. CONCLUSION: Mycorrhization was found to stimulate growth to obtain a higher biomass of plant leaves in a short time, avoiding chemical fertilization, while analytical results demonstrate that there is an alteration in the distribution of polyphenols in plants colonized by the symbiotic fungus, which can be related to an improvement in nutritional properties with future industrial significance. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Aims: Plants on coastal sand dunes are subjected to strong environmental fluctuations which affect their growth and survival. Sea water invasion of the dunar zone caused by storms is an important factor that determines the persistence of a plant community. In the present study, the benefits of arbuscular mycorrhiza on psammophilic plant species subjected to sea water flooding episodes were evaluated under controlled conditions and the effect of sea water on in vitro spore production was determined. Methods: In a greenhouse experiment, the growth response of nine plant species to inoculation with Glomus intraradices in beach sand was evaluated. A second experiment was designed in order to test if plant survival under sea water flooding was influenced by the symbiosis. A third experiment was conducted in vitro to quantify the effect of sea water on the production of G. intraradices spores. Results: Glomus intraradices was effective in promoting plant growth and survival in beach sand and promoted the survival of some species subjected to flooding events. Spore production was inhibited by 50% of sea water in the growth media, but not by 10% sea water. Conclusions: Results obtained under controlled conditions indicated that arbuscular mycorrhiza can improve the establishment of certain dune plant species in beach sand as the symbiosis contributes to enhanced plant tolerance against occasional sea water flooding. [ABSTRACT FROM AUTHOR]