Abstract

CRUZ, Andre F. Plant and bacterial extracts involved on arbuscular mycorrhizal fungus stimulation and pathogens suppression. Bioagro [online]. 2015, vol.27, n.2, pp.103-110. ISSN 1316-3361.

‘Amanatsu’ orange (Citrus × natsudaidai Hayata) seedlings were cultivated under aluminum [Al₂(SO4)₃)], salinity (NaCl) and water stress conditions in green house. ‘Amanatsu’ root extracts (ARE) were obtained from these plants by using a flash chromatograph, and an experiment in vitro to measure the effect of the extracts on hyphal growth of arbuscular mycorrrhizal fungus (AMF) was carried out. The hyphal growth was stimulated by ARE from aluminum and water stressed plants, whereas it was inhibited by ARE from the plants with NaCl. In particular, the hyphal growth in Petri dishes with ARE from aluminum and water stressed plants were around 70 % higher than that with agar only. In a second experiment, the 25 % MeOH eluates of Bahiagrass (Paspalum notatum) and millet (Pennisetum glaucum) root extracts stimulated, in vivo, AMF infection on trifoliate orange (Poncirus trifoliata) rootstocks. A third experiment was carried out to evaluate bacterial extracts on AMF (Gigaspora margarita and Glomus clarum) hyphal growth and soil-borne plant pathogens suppression. The results indicated that the 25 % MeOH fraction could stimulate the hyphal growth whereas mainly the 75 and 100 % MeOH fraction inhibited the pathogen growth in vitro.

Keywords : Aluminum stress; hyphae; methanol fractions; salinity; water stress.

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