This may come too late even for the southern hemisphere but here’s a preliminary observation of some interest, at least to me. I had a lot of Country Dancer seed obtained last fall, and maintained in a frig for a while. Dec 31 I took batches of 200 seeds and put them into moist vermiculite. Different ions were added to the wetting solution with 2 parts by wt of solution to each wt of vermiculite. Today I planted 100 sprouted seeds of the 10 mM calcium nitrate treatment. There were a few already a month ago. Potassium nitrate was only about half as good, and doubling the calcium nitrate was too much and germination was yet lower. Potassium chloride was ineffective. The control of distilled water has shown only half a dozen germ. out of 200 so far.
Nitrate has been reported to stimulate a number of species, but the one report I recall for roses indicated that it had no benefit. So I was a little surprised.
This project is on-going and detailed results will come only next winter. Stratification in peat, which is usually highly effective, so far has been nowhere near so many germinating as for the nitrate/vermiculite lot.
Larry, what was the condition of the pericarps when you planted them? Were they soft and porous by any chance? My thought is that the nitrate promoted growth of critters that break down the pericarp tissue.
Apparently “Epsom salts” (magnesium sulphate) diluted in water may also accelerate germination of some (vegetable) seeds, if it is applied to the soil just after the seed is sown, as one single application.
This is an old gardener’s tip passed on from prior generations locally. The supposed mechanism of action is that magnesium ions may boost enzymatic processes necessary for germination of some (vegetable) seeds.
I have no idea how relevant this is to rose achene germination.
Refer to the link below if you are interested to see the source of this information. It happens to be my usual Saturday evening local gardening show on TV, which I love watching!
Don, I’ve just sown put the tomato-treated Westerland seeds into peat in the fridge along with the untreated ones. I still have some of the ‘Prairie Peace’ seeds you sent me… how about I try Larry’s Calcium nitrate solution on these to see if I can get any non-invassive germinations of it (it’s notoriously difficult normally isn’t it?).
If I knew more at the moment I’d let you know. I chose calcium nitrate because it stimulates binding of Evans Blue dye to roots so I had it and the other ions, in the lab for tests with sunflower plants. For the dye binding calcium is better than magnesium, and nitrate is better than chloride or sulfate. Can’t do calcium sulfate- that’s gypsum. I forgot to mention that calcium chloride was not very good. I would have expected potassium nitrate to be best if it was microbial action that was stimulated. What I can say is that the achenes have turned pitch black with the calcium nitrate so there’s a lot of oxidase stimulated.
It maybe timing not total germination that changes. I don’t think that’s the case but I just have to wait until the end of the year. I know vermiculite and peat moss are different and I’d always thought that peat was best, but now I wonder. I have trials of metro-mix going too.