tailieunhanh - Báo cáo khao học: "Effect of high temperatures on cone opening and on the release and viability of Pinus pinaster and P. radiata seeds in NW Spain"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Effect of high temperatures on cone opening and on the release and viability of Pinus pinaster and P. radiata seeds in NW Spain. | Ann. For. Sci. 59 2002 327-334 INRA EDP Sciences 2002 DOI forest 2002028 327 Original article Effect of high temperatures on cone opening and on the release and viability of Pinus pinaster and P. radiata seeds in NW Spain Otilia Reyes and Mercedes Casal Área de Ecología Dpto de Biología Fundamental Fac de Biología Univ de Santiago de Compostela 15782 Santiago de Compostela Spain Received 5 February 2001 accepted 29 August 2001 Abstract -Pinus genus is characterized by woody cones able to open even after a forest fire which also protect seeds from damages during the fire. The aim of the present study is to analyze the effect of high temperatures on pine cones opening as well as the releasing and viability of the seeds of P. pinaster and P. radiata throughout a selection of different combinations of temperatures and time exposures. During a forest fire extremely high temperatures have a very low remanence. 26 different combinations were selected beginning by 500 C 1 min and then gradually increasing time exposure whereas the temperature on the opposite was set lower and lower. This process was applied up to combinations of relatively low temperatures and long lapses of time such as 100 oC 30 min. 5 cones from each species were tested with each combination a total of260 cones were finally set under study. P. pinaster species showed a scales opening of 50 on average whereas P. radiata neared 90 . The rate for P. radiata seeds releasing is also higher than P. pinaster s. Finally the viability of the seeds remained unchanged under the influence of thermal shocks for both Pinus species. fire high temperatures pine cone opening P. pinaster P. radiata Résumé - Effet des hautes temperatures sur l ouverture des cônes la dissemination et la viabilité des semences de P. pinaster et P. radiata du NO d Espagne. Le genre Pinus présente des cônes ligneux qui protègent les semences du feu et qui s ouvrent même après le feu. Le but de cette étude est de connaĩtre l effet des