Adaptation of Aspergillus niger to short-term salt strees

Adaptation of filamentous fungi to short-term salt stress has been analysed by a continuous measurement system. Spores of Aspergillus niger were immobilized on the polylysine-coated glass bottom of a culture vessel, which enabled the exchange of a medium containing salt (NaCl) without disturbing continuous observation. Repeated contacts with 0.75% NaCl produced hypha insensitive to this concentration of NaCl. When the NaCl concentration was increased stepwise, the tolerated concentration increased up to 1.25%. The acquisition of such a tolerance to 0.75% NaCl required about 10 min prior contact with 0.5% NaCl. Based on these results, the adaptation mechanism is discussed.