Growth-chamber Trial on Frost Hardiness and Field Trial on Flushing of Sessile Oak (Quercus petraea Liebl) : Genetics of Oaks. IUFRO Proceedings

1993

S. 208-214

9 Lit. Ang.

Unselbständiges Werk

200041661

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 -1.5 and -13Grad 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 -8Grad 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.