George
Could you give more detail on your extraction method
All my attempts so far have ended in disaster so any tips on where to start and what to look for would help.
I can find plenty of seeds to practice on but I would prefer to practice doing it the right way.
Russ
Something else that hits me with this. You’re handling these seeds and they aren’t / don’t appear to be the worse for the wear and tear of being handled.
Those cotyledons are greening up still without direct sunglight?
You’re handling these seeds and they aren’t / don’t appear to be the worse for the wear and tear of being handled.
I think that’s interesting too.
Those cotyledons are greening up still without direct sunglight?
The light-dependent step in chlorosynthesis only requires a single photon per molecule so ambient indoor lighting is sufficient. Photosynthesis, which is then using that chlorophyl to produce sucrose for plant growth, takes all the light that you can throw at it.
Hi all.
The picture below is of the type of box-cutter knife I use in embryo extractions.
When I first started playing around with this idea of mine (early 2009), of course I was slicing into and squashing a lot of embryos. In order to get high percentage intact embryo extractions, I realised it was important to define the long axis of the seed with a few initial key slices. Sometimes it was easy to guess, other times a little more slicing was required to define the long axis orientation of the seed within the achene.
After you get the long axis defined in your head, you then slowly slice away at the hard achene in a direction along/parallel to the long axis of the seed, until you have removed enough achene to identify the cotyledon end of the seed. Now you can slowly extend the attack to remove the entire cotyledon end of the achene.
Soon enough you will end up with the radicle end of the seed buried into what is left of the radicle end of the achene. At this point, a few gentle wiggles on the seed with your box cutter blade usually dislodges the seed out. If it fails to dislodge easily, then a few more careful slices on the achene remnant should do the trick. Damage to the radicle is to be avoided at all costs, so this is the critical and most defining few cuts you will be making…(damage to the radicle spells embryo death).
I then place the seed with its seed coat into a glass of water for a while until it visibly hydrates a bit (it gets firmer and shinier). Sometimes if you are lucky, the seed coat has been sliced a little through the achene removal, and the embryo pops itself out through this slice in the glass of water…(this is very time saving when it happens!!!).
Most of the seeds however have a pretty much undamaged coat if you have been “good at it”, so they require extraction of the seed coat. In such seeds, I then proceed to remove the seed coat by making a very superficial side-ways slice at the cotyledon end of the seed coat, to just reveal the pearly white surface of the embryo underneath.
I then slowly nick away and pull away the seed coat with the box cutter blade, always avoiding getting anywhere near the radicle end. The seed must be handled delicately yet purposefully with the fingers of one hand, whilst using the cutter with the other hand to unfurl/peel away the seed coat layer. Much care is required to not squash the embryo here with the fingers holding it in position. Sometimes the embryo pops out at a critical point of losing most of its seed coat. However, in other cases it does not release itself easily, in which case I do not remove any more seed coat if it is nearing the radicle… Instead, I immerse the semi-extracted embryo into a glass of water until it finally pops itself out.
An advantage to using the box-cutter is that you can slice at short/acute angles which gives you very good control of where you direct the forces, to avoid crushing the embryo underneath. The knife must be very sharp of course, otherwise you will be forcing it too much to make the cuts, and thus risking blunt force injuries to the embryo within.
I hope this explanation is easy to follow.
Have a nice day.
George it is wonderful of you to take the time to spell out your procedure and show us the results of your work.
Years ago there was a unique specimen of R. laevigata that grew at Sequoia Nsy. Mr Moore referred to it as, “Wayside Laevigata”. Apparently he has somehow recevied it as breeding stock from someone at Wayside Gardens sometime earlier. It had exceptionally heavy and leathery leaves. Ironically is was heavily infected with RMV.
While it readily set hips the seed wouldn’t germinate. Mr. Moore apparently never got anything out of it.
A friend from upstate NY and I visited Sequoia one Fall and he took some of this seed home and used embryo excision to grow out one of the seedlings. I think he nurtured his on an agar solution.
I have that seedling here now and have used it in hybridizing. This is the laevigata I have used to make my hybrids. It’s extremely vigorous and also roots extremely easily.
I think embryo excision could be very useful when we get a cross that forms seed but wherein the seed won’t germinate.
This happens relatively frequently for me and I’m sure for others as well.
This also has the potential to answer the question, should we just toss the floaters?
Not off topic: the knife that George uses is available in North America (or at least was available 15 years ago) at stores that sell supplies for doing wallpapering. It is used for cutting wallpaper and the snap off allows easy switch to a sharper edge quickly.
This type of knife is readily available at home improvement stores everywhere.
I use them for budding. They are cheap and and as Ann mentions, the blade can be renewed over and over by snapping off the old section.
I’ve tried telling others about this repeatedly. I was shot down when I made this suggestion years ago at Rosarians Corner. I still don’t see the logic.
Some opt for expensive alternatives. I don’t know why anyone would go the expense of acquiring a budding knife and trouble of sharpening it over and over.
Snapping off the old portion even helps avoid spreading infection.
Give me some old pencils and a utility knife and I am good to go. Frugality and convenience are the Mother of invention.
I forgot to mention that I never toss floaters. I agree with Paul Barden. It’s just as easy to sow all the seed from any given cross. Some fertile seed floats. That’s a fact.
Hi Robert an Ann!
It is great sharing this here with others. More fun for all I say!
Robert, I agree with your comment about the floaters/sinkers test being unreliable as a test for good or bad seed.
I always extract all the seeds, floaters or not. I have observed many cases where the floaters had viable embryos particularly in small seed like multiflora, but also in all other seeds as well.
I have observed many cases where the seed looked big bulky and it also sank, looking very promising indeed, and then surprising me by revealing a dead embryo inside upon extraction.
The adage ‘never judge a book by its cover’ is so true when it comes to rose seed.
Discarding “seed-floaters” is a waste of time, and worse still, means that one day you could toss out that one-in-a-million rose you have been working towards!
Robert, I also FULLY agree with you about the utility of this knife.
Apart from using it in rose embryo extractions more recently, I had been using the same type of knife for all my budding work, ever since 1993 (T-budding, chip budding, and even a modified form of patch-budding using only the one blade instead of a double blade system).
It is truely an old friend to me!
SLOW EMBRYO-1 @ DAY 14 OF “JAR CULTURE”-
The radicle of this tricotyledon is curling around like a snail… In fact any of you that know about the anatomy of the human inner ear (cochlea and the 3 semicircular canals), will see a remarkable resemblance to this confuguration!!!
No rootlet has emerged yet.
SLOW EMBRYO-2 @ DAY 14 OF “JAR CULTURE”-
Here, it appears that a rootlet may be forming as a straight projection from the curled radicle.
The leaves are becoming more defined, but they are still wrapped tightly in this weird cone-like mass.
FAST EMBRYO-1 @ DAY 14 OF LIFE-
This seedling was planted only 6 days after extraction from its seed. The picture was taken this morning at day 14 of its life. Note the true rose leaf.
FAST EMBRYO-2 @ DAY 14 OF LIFE-
This is the other fast seedling of the 4 babies that came from the same hip. It too was planted day 6 post embryo extraction. Like it’s other fast sibbling (pictured above), it too has grown a true rose leaf. This picture was also taken this morning (day 14 of its life).
Here the two faster embryos (now seedlings) are thriving in full morning sun, after such a short time in their lives!!
This demonstrates the awsome power of embryo extraction. It also shows how sibblings from the very same hip, can behave so differently when they are pushed to germinate simultaneously, in the same incubation environment.
Have a nice day all.
By the way, the green things aroung the seedlings pictured above are snail pellets. These pellets have saved countless rose seedlings from devourment, judging by the number of dead slugs I routinely pick off the baits.
On a gardening show on TV last week, someone mentioned the use of gravel as an effective repellant of slugs/snails… Is this true of perlite? If anyone can confirm this is the case, I will certainly swap the perlite for the baits, as I hate all chemicals in my garden!
As more “important” seedlings are emerging for me, I realise that I can use the limited pot space and jar space I have a bit more selectively.
So the demonstration of these 4 babies ends here, with a picture of the root development of the two fastest (at day 14 post embryo extraction).
All 4 are in rose heaven now, but the GOOD thing is that they helped some of us understand some of the secrets of rose embryo growth.
Too many seedlings…too little space, alas!!
Very informative George, thanks so much for the summary. As I am cleaning my seeds every once in a while a seed will split open and I can usually take out the brown seed inside it, but sometimes the radicle is very much attached to the achene and this is where I have a problem, so I am so glad that you posted this to explain how to get the seed out without destroying it. Thanks again
No worries Jeanie.
Thankfully most rose seed is just big enough to allow most of us to easily have a go at this, if we so desire, in a very low-tech manner, and with next-to-zero expense.
Here are some additional tips for rose seed embryo extractions…
After getting good at removing the rose seed from its achene, the next major hurdle is to get confident at nicking/peeling away the inner seed coatings that tightly bind the pearly embryo.
Here is where apples can come in handy…First, get some apple seed, and peel away the outer shiny black layer of the apple seed to reveal the inner seed with it’s papery covering. This is not the apple embryo, it is the apple embryo wrapped with its seed covering… What you now have is pretty much a ‘rose seed equivalent’, without the time consuming achene removal step required to get to it!
You can use apple seed to learn how deep is not ‘too deep’ when it comes to nicking/peeling away the inner seed coatings without damaging the embryo underneath.
Try to visualise the seed as though it were an apple ready to be peeled. Start at one end (the cotyledon-wider end) and peel away in a circular fashion after making the first nick somewhere at the cotyledon end of the seed.
By practicing this way, you will gain confidence and overcome the natural fear of damaging the embryo. You will start to realise the relative resistance that these binding tissues exert when you apply a given force with your your box-cutter blade.