[Effects of elevated salt concentrations on growth, sporulation and pigmentation of Trichoderma spp].

On agar media supplemented with NaCl (5% = 856 mM), seven Trichoderma species aggregates and an isolate intermediate between T. harzianum and T. viride (T. 410) grew more slowly, sporulated poorly, and there was no characteristic pigmentation of the colonies. NaCl or KCl concentrations inducing 'albinization' differed with different isolates. CaCl2 (90-270 mM) reversed the anti-sporulating effect of NaCl (856 mM) on T. 410, and stimulated conidiation in media with no NaCl added. Gliocladium virens but not G. roseum, reacted like Trichoderma to NaCl. Fourteen other fungal genera offered various reactions. Since 856 mM NaCl decreases osmotic potential (eta) of the media used from-1.2 to -41 bars, the influence of eta on T. 410 was examined. After 3 to 4 days, maximal growth was observed between-1.2 and -10 bars. Growth was reduced to 50% at about -30 bars. No growth occurred at about -90 bars. No pigmentation was observed at -32 bars (NaCl) and -41 bars (KCl). Abundant sporulation and pigmentation occurred at -31 bars with CaCl2 as sole electrolyte added. Na+ was toxic at high concentration. Results are discussed in view of possible use of Trichoderma in biological control.