EFFECTS OF HIGH-TEMPERATURES ON GERMINATION OF PINUS-HALEPENSIS MILL AND P-PINASTER AITON SUBSP PINASTER SEEDS IN SOUTHEAST SPAIN

Seeds of Pinus halepensis and Pinus pinaster subsp. pinaster were subj ected to four heat treatments (90, 110, 150 and 200-degrees-C) for 1 a nd 5 min to investigate their tolerances to high temperatures resultin g from fires. Another group of seeds of each species were not heated a nd considered as a control. Information on responses of seeds to high temperatures would help to determine whether or not the species are py rophytes. Heating for 1 min at all temperatures did not affect the ave rage germination of Pinus halepensis seeds whereas that of P. pinaster subsp. pinaster seeds was decreased significantly when they were heat ed to 200-degrees-C. However P. pinaster seeds were more resistant tha n that of P. halepensis when heat treatment was 150-degrees-C for 5 mi n. Data obtained also indicated that, in general, P. halepensis and P. pinaster subsp. pinaster seed germination is not favoured by a temper ature increase that can be reached in soils during a fire. Thus, the s pecies are not pyrophytes but colonizers of burnt sites.