GERMINATION ECOLOGY OF MEDITERRANEAN SPECIES FROM NATURAL "LIVING WALLS"

In the perspective of a natural “living walls” building, the germination characteristics of 10 xerophytic species, native to the Mediterranean environment, were studied. Their immediate utilization is unfeasible as the majority of tested species has pronounced seed dormancy. Experiments were conduced in vitro in Petri dishes incubated in climatic chambers regulated to different light and temperature conditions. In the cases of deep dormancy several physical, chemical and/or physiological seed treatments were tested to improve germination. Seed treatments showed that greatest success in dormancy breaking was obtained by chilling, although in some species gibberellic acid (GA₃) or sodium hypochlorite treatment proved more effective, indicating the physiological nature of germination inhibition. In Convolvulus cantabrica dormancy was shown to be physical, as it was removed by seed coat scarification. More than half of the species displayed light-dependent germination, above all in small seeds. Seedling emergence was obtained from different burial depths. Depth-mediated germination inhibition was inversely correlated with weight of 1000 seeds, and smaller seeds required very shallow sowing