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Seed dormancy related to foliage dormancy?

Posted by swontgirl_z5a 5a (My Page) on
Sun, Feb 17, 13 at 17:10

I've got a question about daylily seeds that maybe some of you can help me with.
I have always started my seeds by soaking them in water and peroxide at room temp or on a heating map. When each seed germinates I plant it. It has usually worked pretty well.
This year I wasn't going to start them until March. After reading about soaking them for 3 days and then putting them back in the fridge for cold stratification I decided I was going to try this. I thought it would still end up with them starting about March. So I put some water/peroxide solution in their little bags and soaked then for 3 days. After 1 day I had quite a few seeds germinating and had to plant them So much for March!
I assume these were not dormant and didn't need any cold stratification. Is this the same as non-dormant foliage and will these plants have non-dormant foliage?
Also some of these crosses that germinated right away have some straggling seeds that haven't germinated. I am putting them back in the fridge for cold stratification to see if that helps. Does it make sense that some seeds in a cross can be dormant and some non-dormant? I know I have seedlings in the same cross with differing foliage types. Does the same thing happen in seeds and does this relate to foliage type?
Debbie


Follow-Up Postings:

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RE: Seed dormancy related to foliage dormancy?

I don't know about the foliage vs. seed properties, but I can tell you this:

I don't do any seed prep aside from refrigerating them for two weeks before planting. After planting them last summer, some germinated within a few days, and others took over a month to sprout. I don't know what makes some sprout faster than others, but I've learned not to give up on them too quickly.

Nate


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RE: Seed dormancy related to foliage dormancy?

Thanks Nate. I agree about not giving up on them. Wonder if it has to do with dormancy.
Doesn't anyone else have any thoughts on this?


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RE: Seed dormancy related to foliage dormancy?

I think that's the general consensus, that seeds from evergreen plants do not benefit from cold-moist stratification. I wonder if you maintained cold temperatures when you soaked the seeds for 3 days. If not, 3 days at room temperatures in a moist, oxygen rich environment is enough to start the germination process. I do know there will be a mix in foliage types from a particular cross. I think it's safe to say there will be a mix in seed tendency as well. But I don't think that's the only factor involved. Some seeds will take up moisture more readily than others, and therefore germinate quicker. Seeds need oxygen, moisture and temperature to germinate, so if any one is limited, the seed will be slow to germinate. It would be a good experiment to conduct, but one that has never been important enough to me.
Good luck, Ed


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RE: Seed dormancy related to foliage dormancy?

Hi Ed,
I didn't maintain the cold temp for the soaking -just room temperature.
But not all germinated then.
I guess I am surprised that I never thought that there may be dfferent seed types in one cross before. I just soaked them until they all germinated. Sometimes it took a while!
I will be interested to see how fast the seeds I put back in the fridge will germinate once I take them out.
I have always thought the seeds would act like the pod parent as far as germination etc goes. But there's really no reason that should be the case-or is there?


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RE: Seed dormancy related to foliage dormancy?

I have not noticed any relation between the speed of germination and foliar habit but believe, in addition to the required environmental factors, there's a genetic factor involved. For example, any cross I've ever harvested using dormant Tennessee Flycatcher as either pod or pollen parent has always had at least one seed already germinating in the pod. Seeds from the pod parents Odds And Ends and Swallow Tail Kite, both registered as SEV but acting dormant here, plus the dormant Platypus Pam, are always among the first to germinate.

I soak the seeds in the fridge for 2-4 weeks (the longer time period for crosses of 100+ seeds) before placing them at room temperature because it seems to induce a more uniform germination with fewer stragglers. I also use the longer period for 1 - 5 or so seed crosses because they're often otherwise hard to germinate.


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RE: Seed dormancy related to foliage dormancy?

So do you think all seeds need the cold stratification or are the ones that don't just tolerating it and not germinating because they are in the fridge?
I am not sure it was the speed of germination I was wondering about - just whether some seeds need cold stratification or not. And can some seeds of a certain cross need it while others don't.
Debbie


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RE: Seed dormancy related to foliage dormancy?

So do you think all seeds need the cold stratification or are the ones that don't just tolerating it and not germinating because they are in the fridge?

No, primarily seeds from genetically dormant plants benefit from the cold-moist stratification. Putting the seeds in the refrigerator inhibits the germination of all seeds.

I have always thought the seeds would act like the pod parent as far as germination etc goes. But there's really no reason that should be the case-or is there?

Some may act like the pod parent, but I don't believe there's any reason it should always be so, even in the same cross. The plants we are dealing with are hybrids, and therefore the seeds will be a mixture of their parent's genetic heritage.
Ed


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RE: Seed dormancy related to foliage dormancy?

Whether a daylily seed needs cold stratification or not to germinate rapidly is a very complex situation.

When, where and how one grows the parents affects whether a seed is 'dormant' or not when it is mature in other plants and are likely to affect daylily seed dormancy.

For example, if someone crosses cultivar A with cultivar B in a southern location and their seeds mature in July or August and I cross the same two cultivars in my garden but the seeds mature in October then the southern seeds may not be the same as the northern seeds in dormancy.

For example, if I collect some seeds in October from a cross and leave them at room temperature until April and then plant them they may not be dormant and they sprout quickly. If I plant them in October they may be dormant and none sprout unless they are cold stratified first.

The growing conditions and environment affect seed dormancy.

Then there are genetic effects. Cross A x B may produce seeds that are dormant and require cold stratification to germinate rapidly while cross C x D produces seeds that germinate rapidly without cold stratification (when all other environmental or growing conditions are the same for the two crosses). Not all seeds in a cross may need cold stratification since whether a seed needs it or not depends on its own genetics as well as its environment.

It is possible that whether the plant is dormant or ever-growing affects whether its seeds need cold stratification or not but the comparisons must be made under identical growing conditions and I don't think that has been done.

[An aside]
An important point. When a plant is a dormant it is not a foliage characteristic; it is a bud characteristic that affects the growing point or technically the apical meristem. A daylily may have green leaves but be dormant. A daylily that has yellowing and dying leaves and no new green leaves are growing is likely to be dormant at that time but may have become dormant many weeks or months before.

In my growing conditions and location plants such as 'Ophir' and 'Heavenly Harmony' as two examples, stop producing new leaves in June or earlier. Those leaves stay green until the autumn. 'Ophir' grows no new leaves (usually) and so is dormant from July to the next spring. Its leaves do not yellow and die until late October or early November but it is dormant continuously from July or earlier. 'Heavenly Harmony' on the other hand usually keeps its leaves until early September and then they die rapidly and its fans produce a few very short sprouted leaves barely above the soil surface. It is probably dormant continuously from June and then after its leaves die the bud barely sprouts before cold weather stops its growth.


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RE: Seed dormancy related to foliage dormancy?

Thanks,
This does answer my question as to whether or not the seeds of one cross could behave differently regarding germination.
It is difficult to believe that seeds from the same cross can be affected by environmental factors so much. I don't know how they can figure out where they live but I guess they do!
Regarding dormancy, are you saying a non dormant daylily will continuously be making foliage buds throughout the season? When it lives in a cold climate it dies off in the winter but is happy to start growing again in the spring and when it lives in a warm climate it keeps growing making new buds throughout the year.
So a dormant plant stops making buds at some point in the season and then dies when winter comes here. I assume it needs this rest to start making buds again, explaining why it wouldn't be happy in a warm climate?
Debbie


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RE: Seed dormancy related to foliage dormancy?

Regarding dormancy, are you saying a non dormant daylily will continuously be making foliage buds throughout the season?

A non-dormant daylily will continuously produce new leaves and never make a bud, as long as the temperature and other conditions allow growth.

When it lives in a cold climate it dies off in the winter but is happy to start growing again in the spring and when it lives in a warm climate it keeps growing making new buds throughout the year.

In a cold climate a non-dormant daylily will stop producing new leaves and not make a bud - it will simply stop growing. In a warm enough climate it will coninue to grow and produce new leaves and not make a bud.

So a dormant plant stops making buds at some point in the season and then dies when winter comes here.

The dormant plant stops making new leaves at some point in the season and then makes a bud. The bud can be made very early in the season but it is what lives over winter and sprouts the next year in the spring.

I assume it needs this rest to start making buds again, explaining why it wouldn't be happy in a warm climate?

If dormancy in daylilies is like dormancy in trees then the dormant daylily needs a winter period of cold to allow its bud to start growing properly again in the spring. If the bud does not experience enough cold weather it would not start to grow or would not grow properly in the spring. In a warm climate some dormant daylilies might not experience enough cold and might not be happy. Although many daylily growers believe this, there has not been enough published scientific research to strongly support this. There has been some unpublished scientific research that suggests that most dormant daylilies do not need any cold to grow properly and some research by Arlow Stout that suggested that a few dormant daylilies do need some cold to grow properly.

Maurice


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RE: Seed dormancy related to foliage dormancy?

Thanks Maurice
So are you saying that non-dormant daylilies never produce buds? I guess I never thought of this. I was thinking each bud produced a leaf but each bud produces a new fan. If a plant is growing and making additional fans would there not be a need for new buds whether dormant or not?
I have often wondered when exactly plants make more fans. Some seem to be there in the spring and some seem to keep adding over the summer.
Debbie


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RE: Seed dormancy related to foliage dormancy?

So are you saying that non-dormant daylilies never produce buds? I guess I never thought of this.

A non-dormant should never produce an over-wintering bud. But the situation is very complex.

When a daylily seed sprouts it grows into a fan. To do that it has a special area that produces baby leaves one after the other.That special spot is commonly called the growing tip or the growing point. In other plant species that have stems with leaves along the stems the growing point is at the top of the stem. In daylilies the growing point is in the middle of the fan covered by many layers of baby leaves. Scientists call that special spot the shoot apical meristem or SAM for short.

To begin with the seedling fan is small and as time passes it grows larger. It cannot produce flowers until it becomes its mature size. Until it becomes mature the SAM is called vegetative and it only keeps making baby leaves (which grow longer until they reach their adult size).

In a non-dormant daylily the SAM will never become an over-wintering bud. It will continue to produce new leaves until the fan becomes large enough to flower (until the fan becomes adult or mature). When the fan is mature the SAM stops making baby leaves. The SAM stops being vegetative and becomes a baby scape. It becomes reproductive. All the time that the SAM was vegetative and making baby leaves it kept growing but once the SAM becomes the scape it gets all used up.

If that is all there was then the fan would die. But it does not die. Like most plants daylilies can produce a new meristem but this one develops in the corner between a leaf and the crown. It is called an axillary meristem and once the original SAM becomes a scape one or more axillary meristems develop to replace the original SAM. If only one axillary meristem develops then the fan remains just one fan. If two axillary meristems develop at the same time then the single fan becomes two fans.

Truly non-dormant daylilies should grow forever under ideal conditions and never develop an over-wintering bud. They would flower, grow new leaves, flower again, get larger, produce more new fans and repeat everything as long as the growing conditions allowed growth. If the conditions are not good, its too cold or too dry and so on then the non-dormant daylily can stop growing but it should not develop a bud. When the conditions become good for growing again the fan should start growing again.

In a dormant daylily, something at sometime signals the daylily to make an over-wintering bud. When the fan experiences the signal it stops making baby leaves. In a vegetative bud it makes a few special modified leaves called bud scales. Then it makes a few baby leaves and then it stops doing everything to the unaided eye. The budscales protect the baby leaves and the SAM. The bud is present during the winter and starts to grow in the spring. It may be completely underground or it may be as much as an inch or two above ground.

For a reproductive bud in a dormant daylily there are a few budscales, some baby leaves and a tiny scape in the bud. When the SAM becomes the scape one or more of the axillary meristems start to develop to become the new replacement SAM for another growth cycle. For reproductive buds in dormant daylilies there will often be a bud within the bud.

I was thinking each bud produced a leaf but each bud produces a new fan. If a plant is growing and making additional fans would there not be a need for new buds whether dormant or not?

There is a need for a new active meristem to create the new fan. We do often write the word 'bud' when it should only be meristem or SAM or axillary meristem. A bud is a resting stage so when the plant is growing we should write growing tip or growing point or shoot apical meristem or SAM.

The fans of all daylilies have the potential ability to make new axillary meristems in the angle between every leaf and the crown. Most of the time there may not be an axillary meristem until they are needed. Research is needed to determine when axillary meristems develop.

I have often wondered when exactly plants make more fans. Some seem to be there in the spring and some seem to keep adding over the summer.

I think that may depend on whether the cultivar is dormant or non-dormant. If it is non-dormant then every time the fan flowers it can make a new fan and that new fan will start to grow right away (because it is not dormant). If it is a dormant then when it makes its new fan the axillary meristem for that new fan may be dormant right away. In that case it does not grow until the next growth cycle which is usually the next spring.

Fans can also make new fans without flowering. That may depend on how fast the fan fan grows and how large it becomes. Researchers would call making new fans 'branching' and would consider 'apical dominance' to be important for that. Apical dominance means that a vegetative SAM does not allow axillary meristems to develop.But there are many environmental factors that can affect the vegetative SAM's ability to prevent the axillary meristems from developing.

Maurice


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RE: Seed dormancy related to foliage dormancy?

Maurice,
So let me see if I have this straight. Even though a non-dormant daylily could keep growing in ideal conditions, any given single fan doesn't keep growing. Once it has matured and flowered it is replaced by a new scape from a new meristem? Would this mean non-dormant daylilies seem to multiply after the bloom season?
Can any of this explain fans splitting? I have heard of this happening but I'm not sure I've ever really seen it.
I will have to try and watch which cultivars seem to have more fans in the spring and which ones continue to add fans over the summer.
Thanks for correcting my use of the word bud.
Debbie


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RE: Seed dormancy related to foliage dormancy?

Even though a non-dormant daylily could keep growing in ideal conditions, any given single fan doesn't keep growing. Once it has matured and flowered it is replaced by a new scape from a new meristem?

Once the fan has matured and flowered it will be replaced by a new fan from a new meristem and it will eventually produce a new scape.

Would this mean non-dormant daylilies seem to multiply after the bloom season?

Because non-dormant daylilies can grow whenever the conditions are suitable they can multiply whenever the original SAM has converted to a scape, even if the scape has not yet grown large enough to be visible to us.

I have tried to upload a drawing of a fan from a dormant daylily showing two new buds. Since it is dormant it will not grow new leaves until the next spring so neither bud will start to grow until then.

I am going to upload a drawing of a non-dormant daylily showing two new fans in the next message.

Can any of this explain fans splitting? I have heard of this happening but I'm not sure I've ever really seen it.

I'm sorry, don't know what is meant by "fans splitting".

Maurice


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RE: Seed dormancy related to foliage dormancy?

In this drawing there is a non-dormant daylily that has a visible scape and two new fans started to grow. The leaves of the new fans will be visible at the same time or even before or after the scape starts to have open flowers.

Maurice


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RE: Seed dormancy related to foliage dormancy?

Fan splitting is when a fan gets large enough that it splits into 2 fans. Is this a just an old wives tale?


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RE: Seed dormancy related to foliage dormancy?

Both drawings show how one fan becomes two fans naturally.

One can split a fan with a knife into two parts that can each become a new fan but the natural way that one fan becomes more than one fan requires that axillary buds develop into new fans.

Maurice


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RE: Seed dormancy related to foliage dormancy?

I was looking carefully at my seedling bed, and I think I'm seeing what Debbie was calling "fan splitting." It's hard to get a good photo of it, but what I'm seeing, essentially, is a big single fan that now seems to have two growth centers.

I'm posting 3 photos. The first is one seedling that appears to be splitting, the second is a different seedling doing the same thing, and the third is an overhead image of the second seedling.

I'm hoping this means that they will begin flowering soon, but at the very least I think it means they are growing well and increasing.

Nate


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RE: Seed dormancy related to foliage dormancy?

Second seedling


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RE: Seed dormancy related to foliage dormancy?

Second seedling, top view


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RE: Seed dormancy related to foliage dormancy?

Yes Nate- that is what I meant. I never realized others hadn't heard of it. I thought it was quite common. I will have to watch for some this year too but it will be another few months before I can see any especially at the rate our snow is melting!
Debbie


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RE: Seed dormancy related to foliage dormancy?

Well I looked closely at those two seedlings again yesterday, and they've both got visible bloom scapes starting. So that fits what Maurice said about the new fan being associated with a bloom scape. Now I'll be curious to see whether the plant becomes two fans permanently.

Nate


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