Fire-Related Cues (Heat Shock and Smoke) and Seed Germination in a Cistus creticus Population in Southwestern Turkey

Abstract

This study investigated the relationship between fire-related cues (heat shock and smoke) and the germination behaviour of Cistus creticus (Cistaceae) seeds under laboratory conditions. The seeds were obtained from a long-unburned Pinus brutia Ten. forest located on the Bozburun peninsula, Muðla, Turkey. Heat treatments were carried out at 80, 100, 120, and 150°C for five minutes. For smoke treatments, seeds were incubated in a liquid smoke solution for 24 hours. Both dry and watered controls were included in the experiment for heat and smoke treatments, respectively. Extra treatments of heat and smoke combinations and a cold stratification treatment were also performed. The treated and untreated seeds were sown into Petri dishes containing agar as a substrate, and the germinations were monitored until the end of the experiment. When compared with the control, the heat shock of 100, 120 and 150°C had significant stimulatory effects on the germination response, whereas 80°C, smoke and cold stratification did not. The results of the heat treatments are in accordance with current literature, but there is still a need for more studies for the comparison of the smoke treatment. In summary, the results indicated that seed germination of the considered population of C. creticus is stimulated by moderate and high heat intensities, but not by low heat intensity and smoke. It is important to know the germination response of plant species to fire cues for better management decisions in fire-prone woodland ecosystems.