Decline in a seed-specific abscisic acid-responsive glycine-rich protein (GRPF1) mRNA may reflect the release of seed dormancy in Fagus sylvatica during moist prechilling

Abstract

Dormancy and desiccation tolerance were studied inFagus sylvaticaseeds subsequent to 0–26 weeks of either moist prechilling (5°C) or warm (15°C) pretreatment at a restricted water content of 34% (fresh weight basis), i.e.c. 5% below full imbibition. After the pretreatments, seeds were either fully imbibed at 5 or 15°C, or dried for 7 d to around 13% moisture content and then fully imbibed at 5°C. Most of the dormancy was released after 5 weeks of prechilling, with nearly 70% of the seeds germinating at 15°C, and dormancy was fully released after 11 weeks of prechilling. Most of the seed desiccation tolerance, measured as the final germination percentage for dried seeds, was lost between 11 and 13 weeks of prechilling. A further decline in desiccation tolerance was recorded from 13 to 19 weeks, with a moderate recovery after 26 weeks. Germination was compared with the expression of a previously described abscisic-acid-responsive GRPF1 mRNA for a glycine-rich protein inF. sylvatica. There was a clear decline in accumulation of the transcript in seeds during prechilling, but not during the warm pretreatment. The amount of GRPF1 expression correlated significantly (P< 0.001) with dormancy status.