Influence of heat and smoke treatments on the germination of six leguminous shrubby species

Abstract

The effect of high temperatures and smoke on germination was tested on the shrubland Leguminosae species, Adenocarpus lainzii, Cytisus scoparius, Cytisus striatus, Genista berberidea, Genista triacanthos, and Pterospartum tridentatum, which are abundant and widely distributed throughout the north-western Iberian Peninsula. Light thermal shocks (80°C, 5 min and 80°C, 10 min) and medium thermal shocks (110°C, 5 min and 110°C, 10 min) stimulated seed germination in C. striatus, A. lainzii, and P. tridentatum. The treatments 80°C, 10 min and 110°C, 5 min stimulated germination in C. scoparius but only 110°C, 5 min did so in G. berberidea and G. triacanthos. The intense thermal shocks (150°C, 5 min and 150°C, 10 min) inhibited germination in all of the species studied but the inhibition effect was already detectable at 110°C, 10 min in G. berberidea. From the results, it was impossible to relate the different levels of smoke used to the variations in the germination response of the species studied. The increase in the germination level after fire was more important in C. scoparius, C. striatus, A. lainzii, and G. triacanthos, which are non-resprouters.

Effect of fuel treatments and backfiring on the recovery of an obligate seeder-dominated heathland

“…P. tridentatum and U. gallii), as also observed after an experimental fire in this area (Fernández & Vega, 2014) and supports previous research that demonstrated the high resprouting capacity of those species after perturbations (Reyes et al, 2009;Muñoz et al, 2012b) along with a possible increase in heat-stimulated seed germination (Rivas et al, 2006).…”

Resprouting Ability of Six Atlantic Shrub Species

“…Despite this importance for the Atlantic shrubland communities of the North-western Iberian Peninsula, not enough studies on the germinative behaviour of the dominant species and their resprouting exist (Pereiras et al 1987;Moure et al 2001;Quintana et al 2004;Rivas et al 2006). During the first post-disturbance year, the most relevant changes are due to resprouting and germination.…”

Heat shock increases the reliability of a temperate calcareous grassland seed bank study

“…This indicates that the lethal threshold for germination is not passed. Negative effects of heat shock on germination have been demonstrated, in particular when seeds are exposed to temperatures above 100°C (Rivas et al 2006;Torres et al 2006;Vivar-Evans et al 2006).…”

“…Several plant species from Mediterranean regions are therefore known to have their seed dormancy broken by heat shock (Herranz et al 1998;Hanley et al 2001;Rivas et al 2006;Luna et al 2007), a phenomenon also encountered for species occurring in Australian heathland, grassland or forest, south African forests, northern American chaparral vegetation or African savanna (e.g. Keeley and Bond 1997;Kenny 2000;Gashwa and Michelsen 2002;Thomas et al 2003).…”