The lower this proportion, the greater the overall degree of "dormancy".
Thus, seeds remaining ungerminated after autumn had a degree of dormancy low enough to allow at least some germination after the winter.
Mortensen et al. [ 52] suggested that the degree of dormancy of beech seeds is associated with the expression of the ABA-responsive cDNA that is a clone of the dormancy-related gene GRPF1, encoding a glycine-rich RNA-binding protein.
It has also been suggested that salt water absorbed in the husk may increase the matric (osmotic) potential and induce a degree of dormancy (Harries 1981) but this has not been experimentally validated.
Genes were filtered as described in the methods Seed germination is controlled by endogenous factors, such as the degree of dormancy, as well as environmental cues, including light, temperature and water.
Compared with a seed batch with weak dormancy, a seed batch with strong dormancy requires longer and/or closer to optimum and/or repeated environmental event(s) to reduce the degree of dormancy sufficiently to reach a specific germination fraction in any specific environment.
For ecological interpretations we consider that seed dormancy should be regarded as a continuous property of a seed batch (even though it is not known whether it is a continuum or an on off property for a single seed); the degree of dormancy for a seed batch can be reduced, and, for some species, induced again, in response to environmental events and/or time.
This pattern can be explained by a summer start at intermediate and warm climates including a period warm and long enough to lower the degree of dormancy and to lead to germination during autumn, and that the autumn start in the cold climate (5 °C) was well suited for germination for fresh seeds of P. argemone (Fig. 1).
The weak but positive effects on water absorption of the wild alleles for seed dormancy QTLs on LG2 and LG10 might reflect the modest degree of seed dormancy in the wild parent (Table 5).
