Seed longevity

Guest · Posted: Mon Jul 26, 2010 9:24 am Post subject: Seed longevity

Hello there,

I would like to know how long may seeds of Ophrys and Orchis be conserved in the fridge, after their harvest and before they lose much of their viability? More simply put: what is the longevity of these seeds?

Many thanks,
WM.

neil4768 · Posted: Mon Jul 26, 2010 7:44 pm Post subject:

If you dry them and keep them dry a long time, years, if not depending on the species a year is possible.

SzPeter_hu · Posted: Mon Jul 26, 2010 8:52 pm Post subject:

Ophrys seeds germinate after 6 months in nature, Orchis after about 1 year. So they remain viable for this length without refrigerating. If you keep them cool and dry, their life may be extended.

I used 7 year old seeds of Himantoglossum and Dactylorhiza with good results. I believe that most orchid seeds stay perfectly viable for at least 10 years (there are some with short viability but those are the exceptions). The loss of viability isn't a sudden change anyway. Therefore the exact life-time of seeds can't be determined. You can expect that as more and more years go by, less and less percent of the seeds will germinate. The Himantoglossum that I mentioned had about 100% viability after 7 years. Maybe this will decrease to 95% after 10 years, 80% after 15 years and so on. And who knows, maybe 1-2% will be viable even after a century.

Germination percentage of some seeds will increase with time. This means that 1 year old seeds may germinate better than fresh seeds because of the dormancy mechanism of the seeds. This also depends on the species.

Wei Mi · Joined: 26 Jul 2010 Posts: 1 Location: France

Many thanks for your detailed answers.
SzPeter_hu, do you think the close-up observation (binocular microscope) of the embryo characteristics (color, form, turgescence) is an efficient indicator of chances of germination?

SzPeter_hu · Posted: Wed Jul 28, 2010 5:11 pm Post subject:

SzPeter_hu · Posted: Wed Jul 28, 2010 6:54 pm Post subject:

If you need further help, search for detailed information about the TTC method for testing seed viability.

As much as I know, it uses a chemical that is converted to a (photosensitive ?) red pigment in living cells. Any appearance of red colour indicates metabolism (i.e. live embryos) even before the first signs of swelling could be seen.