The Ascophyllum/Polysiphonia/Mycosphaerella Symbiosis. III. Experimental Studies on the Interactions between P. lanosa and A. nodosum

Experiments were conducted to examine the survival of spores, sporelings and apical fragments of Polysiphonia lanosa and the interactions between P. lanosa and potential fucoid hosts (Ascophyllum nodosum and Fucus species). In culture there was no dependency of P. lanosa on A. nodosum for spore germination. Apical fragments of P. lanosa survived longer (half life of over 194 versus 85 days and 119 versus 85 days) in cultures in which fragments of A. nodosum or Fucus vesiculosus were present. Thus substances from fucoids are likely involved in this improved survival (...)