SRGC Seed Exchange 2016-17 No. 70

[Carolyn]

Here's a photo of my eranthis seeds from last year's seedex. I sowed 30 seeds in Jan 2016 after soaking them in dilute GA3 and have got over 20 germinated in this pot (the slugs managed to nibble some). This result is almost as good as with fresh seed, where I would expect over 90% germination. Interestingly, these seedlings appeared about 2 weeks ahead of my own fresh seed, sown straight after harvest last May.

[Cfred72]

The first seeds received on 17 January are already germinating 
I show a photo at the bottom of the page of the following link : http://www.srgc.net/forum/index.php?topic=6490.750

[Rick R.]

Assuming the dry ephemeral seeds are still alive, I had read how a major problem with rehydrating these types of seeds was that if water is imbibed too quickly, the cellular structures can permanently crack.  The action of certain parts absorbing water faster and expanding faster than other parts creates pressure differentials that cause breakage at the cellular level. This breaking of cell integrity leads to the demise of the seed.  This is why The Kew SID sometimes begins hydration of recalcitrant seeds with high humidity rather than liquid water contact.

Well, at least that’s my very basic explanation.  I dare say, if you want to learn all about recalcitrant seed, this pdf will keep you going:
 https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=0ahUKEwjRjPCplOHRAhUk74MKHeCSA9EQFghiMA8&url=https%3A%2F%2Frngr.net%2Fpublications%2Fttsm%2Fch4%2Fat_download%2Ffile&usg=AFQjCNHrCW_b0afzw5Yg1YqGzb6qPeULNw&bvm=bv.145063293,d.amc

In 2015, I did some experimenting with the dried ephemeral seed from the seed ex.
I was blessed by an accidental mistake and received two packets instead of one of Corydalis malkensis (SRGC#1064).  So I had enough seed to try a crude “scientific” trial: 32 seeds planted directly into moist soil and 32 seeds first in a 2x3 inch ziplock bag with a bit of paper towel with the tiniest bit of dampness on it - for 2 weeks, and then planted in moist soil.  Both treatments began on 13 Feb 2015.  While I had planned on working in a cold treatment before spring arrived in Minnesota, it didn’t happen.  They didn’t get their cold treatment until the following natural winter.  They were both treated the same and stayed together through the spring of 2016. 

The RESULTS are encouraging! 
--- The lot planted directly into the soil had no germination.
--- The lot pretreated with 2 weeks of water vapor sprouted 23 out of 32 seeds in March 2016!

Although I didn’t have enough seed to try side by side trials with other species, I did try the same vapor method at the same time with a few other similar type seeds:
Erythronium caucasium
Erythronium revolutum
Cardamine pentaphyllum
Hepatica nobilis

But no seed emergence of any of these.

[Cfred72]

This will do me some work decoding and reading, but this is an article that interests me. Thank you, Rick.

[Carolyn]

Very interesting, Rick. I know some trillium growers use the damp paper towel technique to rehydrate the seeds. I have never tried this, but I think I will next year. I will also try it with corydalis next year.
Talking of corydalis malkensis reminds me of an experiment I did a couple of years ago. On harvesting the seeds, I realised I had picked some under-ripe ones too - the seeds were brown, rather than black. I separated them out and sowed them. The ripe black ones germinated 100%, the brown underripe ones not at all. Always good to experiment!

[Leena]

GA3 is not readily available here, but Rick's method is something I could try.  I have had bad experience with seed ex seeds of Corydalis, so that is why I haven't ordered them lately, or sent them to the exchange because I thought they were going to to waste, but Rick's method could be the answer!

[Véronique Macrelle]

And keep the  seeds  (Corydalis, Trillium... ) after the harvest under plastic with wet paper? Then send them for exchanges in the same packet ...  like this:


 Trillium kurabayashii received 2 weeks ago. Under plastic at 20 ° C
They are well swollen and some radicles point

I hope that what I write is understandable because I use an automatic translator 

[Cfred72]

Hello Veronique and welcome. Do not worry about understanding. It goes well. 

[Diane Whitehead]

what do you think should be done with seeds like Corydalis (and some others like that), which ripen early in the summer. If they are kept dry until January, the germination will be very poor

  For several years someone organized an Ephemeral Seed Exchange.  Those of us who would be offering seeds sent in lists which were distributed.  Anyone wanting seeds would request them from the donor and they would be mailed as soon as they were ripe. 

The other, possibly less complicated thing to do is to send your fresh seeds to Australia and New Zealand, and they would send theirs north.

Diane

[Rick R.]

Let me stress that I was very careful to use the tiniest bit of water.  If I put enough water at one end of a 3x3cm piece of paper towel, and it dampens the entire square, I deemed that as too much water.  But since I can't get thick (freezer type) little baggies that do not breath, I did put the little ziplocks inside a bigger freezer ziplock bag with another, perhaps damper paper towel.

[Gabriela]

Assuming the dry ephemeral seeds are still alive, I had read how a major problem with rehydrating these types of seeds was that if water is imbibed too quickly, the cellular structures can permanently crack.  The action of certain parts absorbing water faster and expanding faster than other parts creates pressure differentials that cause breakage at the cellular level. This breaking of cell integrity leads to the demise of the seed.  This is why The Kew SID sometimes begins hydration of recalcitrant seeds with high humidity rather than liquid water contact.

Well, at least that’s my very basic explanation.  I dare say, if you want to learn all about recalcitrant seed, this pdf will keep you going:
 https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=0ahUKEwjRjPCplOHRAhUk74MKHeCSA9EQFghiMA8&url=https%3A%2F%2Frngr.net%2Fpublications%2Fttsm%2Fch4%2Fat_download%2Ffile&usg=AFQjCNHrCW_b0afzw5Yg1YqGzb6qPeULNw&bvm=bv.145063293,d.amc

An interesting article Rick, there is still so much to be discovered and clarified about the so called recalcitrant seeds. I like the way they refer to the 'continuum of recalcitrant seeds behaviour'.
It is true that some are more recalcitrant than others and no one has done work to make a proper classification (probably would be impossible). That's why we call all Corydalis to be recalcitrant but for sure some species are less than others and so will germinate after getting dry.

Personally, I started to name the period of time after which such seeds will germinate (after getting dry) -  'the dry allowance'. I should have in a year or two data on few Corydalis sp., Aconitum sp. and Callianthemum.
It would be interesting maybe to start a separate thread for this subject, where all can write their findings.

For Hepatica, there are reports of seeds germinating after 3-6 months of 'dryness'. For Epimedium I kept seeds dry till September (+/- 3 months) and they germinated good enough - no imbibition, just plain sowing in pots.

[Gabriela]

And keep the  seeds  (Corydalis, Trillium... ) after the harvest under plastic with wet paper? Then send them for exchanges in the same packet ...  like this:

I hope that what I write is understandable because I use an automatic translator 

We understand very well Véronique, don't worry 
For long term moist storage, keeping the seeds in a small amount of moist vermiculite is a better option than the wet paper.
The moist paper in the enclosed bag can encourage molds and in case the seeds germinate the radicles can get stuck in the paper.

If the Seedex team agrees it would be possible to send already numbered/moist packaged seeds. Some species can be kept in moist vermiculite more than one year with no problems.

[Diane Whitehead]

It sounds good, but it hasn't worked for me.  Starting in 2012 I have received 13 lots of moist-packed
seeds, and not one has germinated.

[Gabriela]

It sounds good, but it hasn't worked for me.  Starting in 2012 I have received 13 lots of moist-packed
seeds, and not one has germinated.

This sort of general statement is not helpful in any way. What species? From seed exchanges or bought from someone?

Of course, if seeds are not collected at the right time or do not undergo the right warm/cold periods, the fact they are moist packed won't help. I can provide a list with species that will germinate for sure if kept moist properly; some in the second year from sowing (mostly the ones with an underdeveloped embryo when collected).

[Diane Whitehead]

They were all from NARGS from the 2011, 2012, and 2013 exchanges.

one lot each of Anemonopsis macrophylla      Helleborus thibetanus    Hepatica maxima    

two lots each of Jeffersonia diphylla    Jeffersonia dubia

one each Trilllium cuneatum    Trillium erectum   Trillium flexipes f walpolei(cf)

three lots of Trillium flexipes hybrid