“Conclusion: In this study, we have uncovered a novel function for the master regulator of seed maturation, FUS3, in delaying germination at supraoptimal temperature. Physiologically, this is important since delaying germination has a protective role at high temperature.”
In a nutshell these folks found that a gene called FUS3 regulates abscissic acid levels in embryos and shows how it varys the level according to temperature, and in conjunction with embryo maturation. This is essentially the basis for the after-ripening effect we continue to discuss here - meaning it is very real and has a genetic cause.
I always thought there was some under lying factor effecting rose germination. Here in OZ , the majority of my germination begins in Autumn (Late March early April). I found that temperatures in the range of 59 to 70 F gave me the best results and anything over 70F germination slowed down. Any seedlings which germinated in the middle of our Spring , to me never do any good, our heat here sems to fry them.
it would be great if someone could advise how to switch this gene’s effect off, so we can germinate these things when we want to.
Maybe there are enzyme blockers out there (?already known to science) which block the chemical pathways which lead to the production of ABA for example that could be added to the mix in order to speed up germinations?
It was several decades ago that deVries and Dubois showed that there is an optimum temperature for rose seed maturation, 22 C, for one particular CV cross (Sonia x Hadley), while there is strong inhibition at 26 C. Likewise Semeniuk and co-workers showed that for germination there is a much lower optimum temperature for the stratification process, and that high temps induce secondary dormancy. The precise meaning of hi depends on CV or species. Very likely roses have the equivalent of the FUS3 gene of Arabidopsis. Thanks, Don for showing this new report.