EFFECT OF HIGH-TEMPERATURES ON SEED-GERMINATION OF 2 WOODY LEGUMINOSAE

Cytisus scoparius and Genista florida regenerate after fire by stump-sprouting but also by seed. Seeds of these species were heated to a range of temperatures similar to those registered on the surface soil during natural fires (from 50 to 150-degrees-C) and a range of exposure times (from 1 to 15 min). No germination was observed at high temperatures, greater-than-or-equal-to 130-degrees-C, when the exposure time was 5 min or more. However, moderate heat treatments (at 70 and 100-degrees-C) significantly increased the rate of germination relative to controls. Cytisus scoparius is more favoured by fire action than Genista florida, with germination rates slightly greater following 100-degrees-C for 5 min and 130-degrees-C for 1 min than after mechanical scarification.