Effect of heat on seed germination of Pinus sylvestris and Pinus nigra ssp. pallasiana

Abstract

The present note presents and explains the results of a study dealing with the germination of seeds subjected to heat. Seeds of Scots pine (Pinus sylvestris L.) and Anatolian black pine (Pinus nigra ssp. pallasiana) were exposed to a range of temperatures (70, 90, 110, 130, and 150°C) for different exposure times (1 and 5 min). Germination rates were similar for all treatments and control at 1 min exposure for Anatolian black pine seeds, and almost no germination took place for all treatments at 5 min exposure. Similar results were obtained for Scots pine seeds, with the exception of a sharp decrease in the number of seeds germinated above 110°C. The effect of increasing the exposure time to 5 min was immediate, and no germination took place above 90°C. Results obtained indicate that seeds of the two species do not necessarily need fire for successful regeneration, but fires may have a positive effect on the germination by removing crown cover, thereby providing more light for the seeds deposited to the ground.