Seeds forum: recalcitrant and semi-recalcitrant* seeds

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Name: Rick R.
near Minneapolis, MN, USA zon
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Leftwood
Feb 19, 2018 7:13 PM CST
SOME RECALCITRANT AND SEMI-RECALCITRANT* SEEDS

Aconitum (Cullina 2004a)
Actaea pachypoda and rubra (Cullina 2004b)
Aesculus pavia (Cullina 2004a)
Allium tricoccum (Cullina 2004a)
Anemone canadensis, caroliniana, patens, and quinquefolia (Cullina 2004b)
Anemonella thalictroides (Cullina 2004b, Deno 1993)
Arisaema triphyllum (Shultz 2005, Genesis seed tests)
Asarum canadense, caudatum, and lemmonii (Cullina 2004b)
Calla (Cullina 2004a)
Caltha palustris (Cullina 2004b, Deno 1993, Genesis seed tests)
Carex flava (Cullina 2008)
Carex laxiflora group (Cullina 2008)
Carex pensylvanica (Cullina 2008)
Carex plantaginea and platyphylla (Cullina 2004b)
Caulophyllum thalictroides (Cullina 2004b)
Chamaelirium (Cullina 2004a) 2
Chrysogonum virginianum (Cullina 2004b)
Cimicifuga americana, racemosa, and rubifolia (Cullina 2004b)
Claytonia virginica (Cullina 2004b, Deno 1993)
Clematis albicoma, crispa, and ochroleuca (Cullina 2004b)
Clintonia borealis, umbellata, and uniflora (Cullina 2004b)
Coptis trifolia (Cullina 2004b)
Corydalis sempervirens (Cullina 2004b)
Cymophyllus fraseri (Cullina 2004b)
Delphinium carolinianum and exaltatum (Cullina 2004b)
Delphinium tricorne (Deno 1993)
Dentaria (Cardamine) diphylla and maxima (Cullina 2004b)
Dentaria laciniata (Cullina 2004b, Deno 1993)
Dicentra cucullaria and spectabilis (Deno1993
Dicentra canadensis, cucullaria, eximia, and formosa (Cullina 2004b)
Diphylleia cymosa (Cullina 2004b)
Diplazium pycnocarpon (Cullina 2004b)
Disporum (Prosartes) hookeri, lanuginosum, and maculatum (Cullina 2004b)
Disporum smithii (Cullina 2004b)
Dryas octopetala (Cullina 2004b)
Epigaea (Cullina 2004a)
Erythronium species (Deno 1993)
Erythronium albidum and americanum (Cullina 2004b)
Fothergilla gardenii and major (Cullina 2004b)
Galax urceolata (Cullina 2004b)
Geranium maculatum (Cullina 2004b, Deno 1993)
Hamamelis virginiana (Cullina 2004b)
Heionas bullata (Cullina 2004b)
Hepatica acutiloba and americana (Cullina 2004b, Deno 1993)
Hydrastis canadensis (Cullina 2004b)
Hydrophyllum canadense and virginianum (Cullina 2004b)
Iris cristata and I. verna smalliana (Cullina 2004b)
Isopyrum (Enemion) biternatum (Cullina 2004b)
Jeffersonia diphylla (Deno 1993) (Cullina 2004b)
Lindera bezoin (Cullina 2004b)
Lysichiton americanum (Cullina 2004b)
Maianthemum canadense and kamtschaticum (Cullina 2004b)
Matteuccia struthiopteris (Cullina 2004b)
Medeola virginiana (Cullina 2004b)
Melanthium hybridum and virginicum (Cullina 2004b)
Mertensia virginica (Cullina 2004b, Deno 1993, Genesis seed tests)
Mitchella (Cullina 2004b)
Oplopanax horridus (Cullina 2004b)
Orontium aquaticum (Cullina 2004b)
Osmunda cinnamomea, claytonia, and regalis (Cullina 2004b)
Pachysandra procumbens (Cullina 2004b)
Panax quinquefolius (Cullina 2004b)
Peltandra virginica (Richard Agnew personal communication, Genesis seed tests)
Phlox (some) (Cullina 2004b) Phlox divaricata (Cullina 2004b, Deno 1993)
Phlox bifida (Deno 1993)
Phlox pilosa (Genesis seed tests)
Phlox glaberrima (Deno 1996)
Podophyllum peltatum (Cullina 2004b)
Polemonium reptans (Deno 1993)
Polygala paucifolia (some) (Cullina 2004b)
Polygonatum biflorum, commutatum, and pubescens (Cullina 2004b)
Pyrola (Cullina 2004a)
Pyxidanthera (Cullina 2004a)
Quercus (Cullina 2004a)
Rosa (Cullina 2004a)
Sanguinaria canadensis (Cullina 2004b, Deno 1993)
Scirpus cyperinus and longii (Cullina 2004b)
Scrophularia lanceolata (Cullina 2004b)
Senecio aureus (Deno 1996, Genesis seed tests)
Shortia (Cullina 2004a)
Smilacina racemosa and stellata (Cullina 2004b)
Spartina most species (Cullina 2008)
Spartina pectinata (Genesis Nursery)
Spartina species (Cullina 2008)
Spigelia marilandica (Cullina 2004b)
Streptopus roseus (Cullina 2004b)
Stylophorum diphyllum (Cullina 2004b, Deno 1993)
Tiarella cordifolia (Deno 1993)
Trillium cuneatum, erectum, grandiflorum, recurvatum, and undulatum (Cullina 2004b)
Trillium grandiflorum (Deno 1993)
Trollus laxus (Cullina 2004b)
Uvularia grandiflora (Deno 1993)
Uvularia grandiflora, perfoliata, and sessilifolia (Cullina 2004b)
Viola (Cullina 2004a)
Xerophyllum (Cullina 2004a)
Zizania aquatica (Baskin & Baskin 1998)

Selected Sources

Bill Cullina 2004, Germination codes for species grown by the New England Wildflower
Society Native Plant Nurseries, 2004 Georgia Native Plant Symposium Papers,
http://www.gnps.org/bc3.htm, accessed 8/01/06.

Bill Cullina 2004b, Germination Requirements of Seeds, 2004 Georgia Native Plant
Symposium Papers, http://www.gnps.org/bc2.htm, accessed 8/01/06.

Norman C. Deno, 1991, Seed Germination Theory and Practice, State College,
Pennsylvania

Norman C. Deno, 1993, Seed Germination Theory and Practice Second Edition, State
College, Pennsylvania

Tara Luna & Kim M. Wilkinson, 2009. 7: Collecting, processing, and storing seeds. In:
R. Kasten Dumroese, Tara Luna, & Thomas D. Landis, editors. Nursery manual for Native
Plants: A guide for tribal nurseries - Volume 1: Nursery management. Agriculture Handbook
730. Washington, D.C.: U.S. Department of Agriculture, Forest Service. p. 113-131.

John M. Row and Richard L. Wynia, 2010, Viability Of Native Warm-Season Grass Seed
Stored Under Two Different Environments Following 35 Years Of Storage, USDA-Natural
Resources Conservation Service, Plant Materials Center, Manhattan, KS 66502, USA

Jan Schultz, 2005, Propagation protocol for Jack-in-the-pulpit (Arisaema triphyllum)
Native Plants vol. 6 no. 2 summer 2005, pp 109-110.
Name: Mark McDonough
Massachusetts (Zone 5a)
Region: Massachusetts Enjoys or suffers cold winters Garden Procrastinator Native Plants and Wildflowers Garden Photography Foliage Fan
Birds Seed Starter Hybridizer Sempervivums
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AntMan01
Sep 10, 2018 10:17 AM CST
Hi Rick, can you define with some specificity the terms recalcitrant, and particularly semi-recalcitrant. I looked up recalcitrant seeds, Wikipedia defines as "Recalcitrant seeds (subsequently known as unorthodox seeds) are seeds that do not survive drying and freezing". I'm thinking that's too simple a definition, because many of the plants on that list like Jeffersonia need to be sown fresh, where they do not completely dry out as they would if stored in a paper seed packet, and do indeed tolerate freezing.

Found a much better description at this link:
www.biologydiscussion.com/plants/verbalization/orthodox...recalcitrant-seeds/23594
Recalcitrant Seeds (Unorthodox Seeds): Recalcitrant seeds are remarkably short-lived which cannot be dried to moisture content below 20-30% without injury and are unable to tolerate freezing. Recalcitrant seeds are therefore, also termed as desiccation sensitive seeds.

The key is the seed must maintain a certain level of moisture content and cannot become fully dessicated. Now it makes sense, for so many spring ephemeral plants, Epimedium should also be listed, drying out the seed is certain death to the seed. The statement "...and are unable to tolerate freezing" is confusing, certainly the seed on most of the items listed do survive freezing (in fact they need it), but perhaps they are talking about freezing dry stored seed, versus sowing the seed fresh into a soil mix that will have a certain level of moisture in it, then remaining in that soil through winter until spring arrives and the seed germinates.

Just harvested seed on Chinese Iris speculatrix (09/05/2018), very happy about that as it has never set seed before, but this year I selfed all the flowers and got 7 pods. Here's seed from one pod, about 30 seeds, with an elaiosome, the giveaway that the seed is likely to be recalcitrant, so it was sown immediately.
Thumb of 2018-09-10/AntMan01/8780e1
Thumb of 2018-09-10/AntMan01/c68389 Thumb of 2018-09-10/AntMan01/379808

I collected seed of 4 pods, got about 100+ seeds, all are sown, and there are two pods left, the bigger one was selfed, the smaller one was a "wide-cross" attempt with final flower on Iris sp. nov. ChenYi#41, I'm going to catch the seed with a nylon bag, the pods split open without any notice.

A reminder of what I. speculatrix looks like in flower, it was rather unceremoniously dug up and put into a box, to be moved to my current location such that I could attend to selfing the flowers and getting seed. A very pretty small evergreen Iris that's hardy here.
Thumb of 2018-09-10/AntMan01/857905

I never knew of this term "recalcitrant seed" ( a good one) to describe the behavior of seed that can't be fully dried. Now I'm wondering what pray tell is semi-recalcitrant seed is.
Avatar: Jovibarba x nixonii 'Jowan'
Allium 'Millenium' - 2018 Perennial Plant of the Year:
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Name: Rick R.
near Minneapolis, MN, USA zon
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Hybridizer
Seed Starter Plant Identifier Million Pollinator Garden Challenge
Image
Leftwood
Sep 10, 2018 6:53 PM CST
Isn't it crazy how we can be so knowledgeable about somethings and still miss some key elements. Although, you knew this concept already, Mark, but just didn't have a name for it.
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
First, my rant on wikipedia:
Everyone thinks it's so great, but here is a challenge: look somethings up in wikipedia that you already know a lot about. Read it with a skeptical eye, and when you find something that doesn't seem quite right, look up the reference given (if there is one!). I will lay odds that the original reference did NOT say what the wikipedia author claimed.

This is why the only time I go to wikipedia is if I just need the basic gist of something. I'll never go there to actually learn about a subject.

But even the second source you quote, well, it's just crowd sourced, too, and with less review than wikipedia. On a different note, I looked at the requirements for article submission at Biology Discussion and was very pleased to see this:
1. Your article must Have Proper English, Which Includes Proper Spelling, Grammar, Punctuation, Capitalization and Sentence Structure.
Hallelujah!
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
The freezing part of the recalcitrance definition has me baffled. I've never heard that before, and my best guess is that they mean a deep freeze as in a freezer at 0-5°F. That would, at least, make sense.

So the traditional view of recalcitrance has been that if such a seed dries (how much is changeable per species), it dies.

Newer data (actually quite old now) has shown that this is not always the case, and often a dry recalcitrant seed is still alive, but dies upon rehydration. People had just assumed the seeds were already dead because the seed rotted in germination attempts.

With these seeds, water is slowly lost in the first stage, the seed's cell walls crumple to accommodate the shrinking volume of the cells. But with the pressure of normal rehydration, the dry and fragile cell walls can't stretch and straighten quickly enough to contain the fast increasing volume of the rehydrating cells. Instead, the cell walls break, causing cell (and seed) death.

Thus, a very simple method is used with varying degrees of success: rather than a normal quick hydration of recalcitrant seeds (as is normal planting), seeds are first placed in a high humidity environment to slowly absorb moisture. Hopefully, this will allow hydration without cell wall breakage. If the seed is alive, this purportedly works well.

As with nearly everything in nature, things are rarely cut and dry, and there are intermediaries here, too. Semi-recalcitrant seeds are somewhere between orthodoxy and unorthodoxy.

I suspect Triosteum pinnatifidum would be semi-recalcitrant. Unfortunately, these two photos are from two different batches of seed, but you will get the gist:
Seed dried a few days:
Thumb of 2018-09-10/Leftwood/00fa6a

Seed dried 18 months and 6 months:
Thumb of 2018-09-10/Leftwood/50d7f9

Name: Mark McDonough
Massachusetts (Zone 5a)
Region: Massachusetts Enjoys or suffers cold winters Garden Procrastinator Native Plants and Wildflowers Garden Photography Foliage Fan
Birds Seed Starter Hybridizer Sempervivums
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AntMan01
Sep 10, 2018 7:32 PM CST
I totally get the Wikipedia rant, as you say, it's useful to get a basic gist of something. With something that's scientific, more complicated or esoteric, forget about it!

Your Triostemon example is most interesting, so much to learn about such variable processes of seed germination. Trial and error (and keen observation) certainly helps. I remember the first year I had seed on Iris odaesanensis and koreana, both Korean woodlanders, seed with eliaosome, I naturally thought it would be a cold germinator (or should I call it recalcitrant seed), but in fact I was surprised when seed planted in June germinated 6 weeks later. For the last 4-5 years, I the fact these two woodland Iris species are warm germinators. Whether the seed can be dried, I doubt it... most likely in nature it can produce seed quick enough and germinate early enough the same year to withstand the oncoming winter.

Another experiment, which can be forced by impatience, lack of familiarity with the seed species, or as happened this year where I had marital woes and separated , moving out to a new "temporary" location, I collected seed on several woodland Iris species prematurely, allowed the pods to dry and ripen in paper envelopes, then sowed them. Two that had been recalcitrant types previously (suaveolens and gracilipes) both germinated in August, way ahead of themselves. Not complaining but go figure. Premature harvest on a few pods of the delightful pale blue Iris odaesanensis (normally white) also showed germination, I will pot them up after the rain influence of the current southeastern USA hurricane is done with. So much to learn. Smiling , thanks for your input.
Avatar: Jovibarba x nixonii 'Jowan'
Allium 'Millenium' - 2018 Perennial Plant of the Year:
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Name: Rick R.
near Minneapolis, MN, USA zon
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Hybridizer
Seed Starter Plant Identifier Million Pollinator Garden Challenge
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Leftwood
Sep 11, 2018 9:54 PM CST
Odaesanensis with a blue tint! Beautifully wonderful! Or, could it have crossed with I. henryi?

Again, and not saying I know more than you, Mark, but you're getting your terms mixed up. Recalcitrance has nothing to do with temperature or types of dormancy. The terms "warm" and "cold" germinator go back to when it was generally thought that seeds germinated best at warm temps (circa 70°F) or cold temps (circa 40°F).

But again, mother nature isn't so cut and dry, and we now know that many many species' seeds don't fit that mold, and germinate best at 50, 60, 80 or 85+°F.

I wouldn't be surprised if Iris koreana and odaesanensis are like many maple seeds: they germinate easily right off the bat, but if the dry, they go into a dormancy that then requires a cold moist period(s) (winter) to overcome.
Name: Mark McDonough
Massachusetts (Zone 5a)
Region: Massachusetts Enjoys or suffers cold winters Garden Procrastinator Native Plants and Wildflowers Garden Photography Foliage Fan
Birds Seed Starter Hybridizer Sempervivums
Image
AntMan01
Sep 12, 2018 8:44 AM CST
From Garden Vision catalog on Iris odaesanensis 'Ice Whisper': "Darrell [Probst] collected a pale lavender-flowered clone in Korea, and grew seed from that plant. This is his deepest lavender-flowered selection. "

What is needed here is a concise definition on "recalcitrant seeds" and "semi-recalcitrant seeds", such that the reader can gain better understanding and value from the plant list given.

Perhaps I don't understand the definition of recalcitrant seed, haven't seen a good definition yet, so I'll just go back to practical experience.

In my personal experience over many years growing and propagating these plants:
Iris odaesanensis & koreana always germinate 5-6 weeks after sowing in June, I refer to this behavior as "warm germinator", just my term, apparently these species do not require a cold period to germinate. This year I selfed 'Ice Whisper', sowed the seed in June, have nice seedling now which I will pot up soon.

Iris cristata seed (from many cultivars) sown immediately when ripe (early summer) has never germinated the same summer, it has always gone through winter and germinated the following spring, I refer to this behavior as a "cold germinator", just my term.

Curiously, never had Iris gracilipes seed germinate the same summer as sowing, until this year I got some sparse gemination, perhaps because seed was exposed to nearly a year's worth of our annual rainfall in July and August alone. My guess is the rest of the seed will germinate next spring, typically I get high germination every spring with this species.
Avatar: Jovibarba x nixonii 'Jowan'
Allium 'Millenium' - 2018 Perennial Plant of the Year:
http://www.perennialplant.org/...
https://www.waltersgardens.com...
Name: Mark McDonough
Massachusetts (Zone 5a)
Region: Massachusetts Enjoys or suffers cold winters Garden Procrastinator Native Plants and Wildflowers Garden Photography Foliage Fan
Birds Seed Starter Hybridizer Sempervivums
Image
AntMan01
Sep 15, 2018 6:50 PM CST
Photo of Iris odaesanensis 'Ice Whisper' flowering early May 2018, followed by photo of 3 seedlings resulting from seed collected off those two flowers (selfed) and sown late June 2018.





Avatar: Jovibarba x nixonii 'Jowan'
Allium 'Millenium' - 2018 Perennial Plant of the Year:
http://www.perennialplant.org/...
https://www.waltersgardens.com...
Name: Bumplbea
Oregon (Zone 8b)
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bumplbea
Sep 25, 2018 9:27 PM CST
This is a very interesting and educational discussion.thank you.
I have enjoyed growing many plants from seed. Funny how some seeds require certain steps in order to germinate. Some seeds are complicated others are easy and germinate isitsu.

Question with the recalcitrant seeds. I understand from the discussion that ...
Some seeds need a cold spell and a damp environment to break their dormancy?
Name: Rick R.
near Minneapolis, MN, USA zon
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Hybridizer
Seed Starter Plant Identifier Million Pollinator Garden Challenge
Image
Leftwood
Sep 25, 2018 10:11 PM CST
Yes, there is lots of variation. Some will require a cold and damp conditioning (simultaneously), some a warm and damp conditioning, some both, some with variations thereof. But none of this is restricted to recalcitrant seeds only.

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