The mycelial growth of 10 Fusarium culmorum strains isolated\ud from water of the Andarax riverbed in the provinces of Granada\ud and Almeria in southeastern Spain was tested on potato-dextroseagar\ud adjusted to different osmotic potentials with either KCl or\ud NaCl (−1.50 to−144.54 bars) at 10◦C intervals ranging from15◦ to\ud 35◦C. Fungal growth was determined by measuring colony diameter\ud after 4 d of incubation. Mycelial growth was maximal at 25◦C.\ud The quantity and capacity of mycelial growth of F. culmorum were\ud similar at 15 and 25◦C, with maximal growth occurring at −13.79\ud bars water potential and a lack of growth at 35◦C. The effect of\ud water potential was independent of salt composition. The general\ud growth pattern of Fusarium culmorum growth declined at potentials\ud below −13.79 bars. Fungal growth at 25◦C was always greater\ud than growth at 15◦C, at all of the water potentials tested. Significant\ud differences were observed in the response ofmycelia to water potential\ud and temperature as main and interactive effects. The number\ud of isolates that showed growth was increasingly inhibited as the\ud water potential dropped, but some growth was still observable at\ud −99.56 bars. These findings could indicate that F. culmorum strains\ud isolated from water have a physiological mechanism that permits\ud survival in environments with low water potential. Propagules of\ud Fusarium culmorum are transported long distances by river water,\ud which could explain the severity of diseases caused by F.culmorum\ud on cereal plants irrigated with river water and its interaction under\ud hydric stress ormoderate soil salinity. The observed differences\ud in growth magnitude and capacity could indicate that the biological\ud factors governing potential and actual growth are affected by\ud osmotic potential in different ways
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