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Keywords:

  • Lichens;
  • photosynthesis;
  • resaturation;
  • velocity;
  • exponential

Summary

Resaturation respiration occurs in Parmelia praesignis Nyl., although it is not strongly developed as in other lichens. Less than 2 h was required for full recovery of photosynthetic ability after having been dry for at least 5 weeks. After three daily, 4 h soaking periods the time for recovery was reduced to 11 min. The resaturation phenomenon is mathematically described for the first time as a negative exponential from which parameters can be derived for maximal net photosynthetic rate, maximal velocity and the velocity at the half-time for recovery. Net photosynthetic rate was independent of the period of drought. The velocity at the half-time for recovery increased by 81% after one soaking period and by 990% after two.