Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Growth-chamber trial on frost hardiness and field trial on flushing of sessile oak. | 208s Ann Sei For 1993 50 Suppl 1 208s-214s Elsevier INRA Original article Growth-chamber trial on frost hardiness and field trial on flushing of sessile oak Quercus petraea Liebl K Liepe Federal Research Center of Forestry and Forest Products Institute of Forest Genetics Siekerlandstr 2 2070 Grosshansdorf Germany Summary The effects of late spring frost on 1-year-old seedlings of 10 European sessile oak provenances at different stages of development were simulated in growth chambers at temperatures ranging between and -13 C. For plants with 1 swollen buds 2 newly unfolded leaves or 3 young fully developed leaves the critical temperature for frost injuries was between -4 and -8 C. Terminal buds lammas shoots and secondary buds dehardened with delay during flushing. Therefore the occurrence of frost damage to particular organs was dependent upon flushing stage at the time of exposure to frost. Following frost injury most plants flushed by producing new leaves from secondary buds. Frost-hardiness variations were observed between the 10 provenances for plants at the same phenological stages. Field studies conducted on 34 provenances revealed that those from southern and southeastern Europe flushed early. Consequently they were more susceptible to late spring frosts than other provenances which flushed later. Quercus petraea I frost hardiness hardiness against late frost flushing growth-chamber provenance variation Resume Variabilité de la resistance au froid et du débourrement Chez le chêne sessile. L effet des gelées tardives a été Simula en chambre de croissance sur des semis d un an de chêne sessile appartenant à 10 provenances européennes. Les temperatures variant entre -1 5 c et -13 c ont été appliquées à differents stades de développement des semis. Les plants ay ant soit des bourgeons gonfles soit des jeunes feuilles repliées sur le bourgeon solt des jeunes feuilles to-talement allongées sont sensibles aux dégâts de gelées à des temperatures variant entre .
