We hope you have enjoyed the SRGC Forum. You can make a Paypal donation to the SRGC by clicking the above button

Author Topic: Chipping-induced instability in snowdrops  (Read 14362 times)

Susan Band

  • Hero Member
  • *****
  • Posts: 842
  • Country: 00
    • Pitcairn Alpines
Re: Chipping-induced instability in snowdrops
« Reply #15 on: February 23, 2015, 07:15:38 AM »
I should explain. Each of the leaves in the picture are a separate bulb.
Susan Band, Pitcairn Alpines, ,PERTH. Scotland


Susan's website:
http://www.pitcairnalpines.co.uk

Matt T

  • Hero Member
  • *****
  • Posts: 1849
  • Country: scotland
  • Nuts about Narcissus
Re: Chipping-induced instability in snowdrops
« Reply #16 on: February 23, 2015, 08:03:11 AM »
I tried to propergate the verified Frit. Imperealis by chopping. I got a really wide variety of verigation. I only have a few ov the coloured left Most reverted to green. Somebody with greater knowledge explained what was happening, something to do with the way the DNA was distributed in the cells.

That's an interesting result Susan (and disappointing for you as a nurserywoman).

I realised that my last post was relevant to the chip vs. twinscale problem, but didn't really answer Anne's original question, why plants propagated from chips aren't stable. I though that could be because:

1. The plastic/undifferentiated cells are not distributed evenly throughout the basal plate, i.e. you might have more stem cells in one chip and less/none in another.
or
2. The expression of features seen in the parent 'drop in chipped offspring are also affected by environmental conditions, either:
a) during the development of bulbils on the chips during incubation, which could lead to permanent changes in the plants; or
b) the growing conditions the resulting plants experience, which you might expect to settle down over time, plants revert according to regime etc.

As Alan says, a huge potential for experimental design to test some of these questions...given enough time and valuable snowdrop bulbs...
Matt Topsfield
Isle of Benbecula, Western Isles where it is mild, windy and wet! Zone 9b

"There is no mistake too dumb for us to make"

Karaba

  • Sr. Member
  • ****
  • Posts: 467
  • Country: fr
    • My 2015-2016 seed list (in french)
Re: Chipping-induced instability in snowdrops
« Reply #17 on: February 23, 2015, 09:34:39 AM »
Are there some cell lines in monocots ? Variagated foliage is often lose due to migration of a cell line in an other.

This is just an hypothesis but chipping mobilise undifferentiated cells and these cells might come from different cell lines. If the pattern of the snowdrop cultivar depend of different cell lines (as the variagated cultivar), chipping might lose one of this cell line and revert to an other cultivar. For example, invert poculiformis might come from an inversion of two cell lines, the inner one becoming the outer one. Chipping might lead to revert the order to the normal one (I'm sorry if it's not fully understandable, but this explanation overcomes my english's limits...).
Yvain Dubois - Isère, France (Zone 7b)  _ south east Lyon

Tim Ingram

  • Hero Member
  • *****
  • Posts: 1955
  • Country: 00
  • Umbels amongst others
Re: Chipping-induced instability in snowdrops
« Reply #18 on: February 23, 2015, 10:06:14 AM »
Have a look at John Richard's Northumberland Diary entry on the AGS website for 26th January 2014. He describes the basis of variegation in dicots (mostly) here in detail (Joe Sharman has given a similar talk to us in the past). Micropropagation runs into these same instabilities (chipping and twin scaling are effectively types of microprop. even if not dividing and manipulating plant tissue so specifically) because plant tissues are quite 'plastic' in the ways they develop (which is what enables them to be vegetatively propagated in the first place) and pigment production in flowers can, after all, be extraordinary (think of irises!). Anne's experiences are really valuable to know.
Dr. Timothy John Ingram. Nurseryman & gardener with strong interest in plants of Mediterranean-type climates and dryland alpines. Garden in Kent, UK. www.coptonash.plus.com

annew

  • Daff as a brush
  • Hero Member
  • *****
  • Posts: 5397
  • Country: england
    • Dryad Nursery: Bulbs and Botanic Cards
Re: Chipping-induced instability in snowdrops
« Reply #19 on: February 23, 2015, 05:26:24 PM »
I'm glad you all came up with comments! A few of my own:
South Hayes when reverted not only loses the green mark on the outers, but the shape of the flower is as a normal snowdrop, totally unlike a proper South Hayes. None of the reverted iPocs that I have kept for observation have shown any attempt to  convert back to either the normal shape or colouring.
I too have theories!
As Karaba mentioned below, parts of an organism can have a completely different genome from the rest of it - these are called chimeras. The classic example of chimerism affecting propagation is in the houseplant Sanseveria. If leaf cuttings are taken from a variegated plant, the resulting plants will be all green. This is because the part of the leaf which produces the new plant is situated on the green part of the variegated leaf, which is different genetically to the yellow part. I wonder if chimerism is involved in the production of iPocs? I need a PhD student to compare the DNA in a reverted iPoc to a perfect one. Please.
Bulbils on chips can be at different places on the chips - they are usually formed at the junction between 2 of the scales and the root plate. If there are more than 2 scales, then there could be several different places along the root plate where the buds are initiated, then there could be differences in the bulbils if there is a difference in the root plate cells depending on where they are located.
As Matt mentions, plasticity may be involved. This can be a change in form of an organism not through a change in its genes, but a change in which genes are switched on or off.
What could cause this change in gene expression specifically in some kinds of snowdrops and not others? Even in some iPoc varieties, but not other iPocs?
Hmmmmm... ::)

MINIONS! I need more minions!
Anne Wright, Dryad Nursery, Yorkshire, England

www.dryad-home.co.uk

annew

  • Daff as a brush
  • Hero Member
  • *****
  • Posts: 5397
  • Country: england
    • Dryad Nursery: Bulbs and Botanic Cards
Re: Chipping-induced instability in snowdrops
« Reply #20 on: February 23, 2015, 05:30:53 PM »
And another thing!
I have never had bulbils produced from an iPoc anywhere on the chip except on the root plate. On other varieties, most notably many of the yellows, I do get adventitious buds arising near the tip of a scale, and sometimes on the tops of the bulb which are cut off immediately prior to chipping. So far these have all produced perfect replicas of the parent bulb.
MINIONS! I need more minions!
Anne Wright, Dryad Nursery, Yorkshire, England

www.dryad-home.co.uk

annew

  • Daff as a brush
  • Hero Member
  • *****
  • Posts: 5397
  • Country: england
    • Dryad Nursery: Bulbs and Botanic Cards
Re: Chipping-induced instability in snowdrops
« Reply #21 on: February 23, 2015, 06:18:14 PM »
Briefly web-surfing. I have got a definition of what we are observing.
"Somaclonal variation is genetic and phenotypic variation among clonally propagated plants of a single donor clone."
Discuss.
MINIONS! I need more minions!
Anne Wright, Dryad Nursery, Yorkshire, England

www.dryad-home.co.uk

johnralphcarpenter

  • Hero Member
  • *****
  • Posts: 2639
  • Country: england
  • Plantaholic
Re: Chipping-induced instability in snowdrops
« Reply #22 on: February 23, 2015, 06:23:34 PM »
Discuss it? I can't even say it!
Ralph Carpenter near Ashford, Kent, UK. USDA Zone 8 (9 in a good year)

annew

  • Daff as a brush
  • Hero Member
  • *****
  • Posts: 5397
  • Country: england
    • Dryad Nursery: Bulbs and Botanic Cards
Re: Chipping-induced instability in snowdrops
« Reply #23 on: February 23, 2015, 07:38:26 PM »
 ;D ;D
MINIONS! I need more minions!
Anne Wright, Dryad Nursery, Yorkshire, England

www.dryad-home.co.uk

mark smyth

  • Hopeless Galanthophile
  • Hero Member
  • *****
  • Posts: 15254
  • Country: gb
Re: Chipping-induced instability in snowdrops
« Reply #24 on: February 23, 2015, 07:44:53 PM »
Susan how did you chop your Frits?
Antrim, Northern Ireland Z8
www.snowdropinfo.com / www.marksgardenplants.com / www.saveourswifts.co.uk

When the swifts arrive empty the green house

All photos taken with a Canon 900T and 230

Tim Harberd

  • Sr. Member
  • ****
  • Posts: 461
Re: Chipping-induced instability in snowdrops
« Reply #25 on: February 23, 2015, 07:50:03 PM »
Hi Ann,
     I understand your need for minions... and I can imagine a few PhDs might be useful... but what blessed use are pigeons, except roast? Apart from having a go at my G. Augustus, they've also been stripping my purple sprouting & pooing on it!!

Tim DH

Chad

  • Newbie
  • *
  • Posts: 41
Re: Chipping-induced instability in snowdrops
« Reply #26 on: February 24, 2015, 09:07:25 AM »
I think there is another process at work here.

It can’t be a ‘plasticity’ issue.  If there were not some totipotent cells [able to regenerate a whole plant] you would end up missing ‘structures’.  In general a meristem that is viable can produce everything [although some may only be able to make roots and some stems]. I think ‘plasticity’ explains the ‘one off’ variations that occur during the production of a single variant flower that is not repeated the next year.

I think what we are seeing here is a genetic switch issue.  Modern genetics recognises both the genetic [DNA] and the epigenetic [which bits of DNA are active] as contributing to inherited component of the phenotype.

If a ‘switch’ is changed, it persists in a more or less stable way through all vegetative propagation [and sometimes through sexual propagation too].  The underlying genetic material is unchanged, but the way of expressing it is.

The more ‘juvenile’ the source of the new plant the greater the risk of a switch being changed, so it would make sense that basal plate new bulbils tend to be more stable than bulbils formed higher up the scale. It also explains why it has been such an issue in micro-propagation.

Roses [sorry] offer an example to illustrate this.  Rosa ‘Iceberg’ is white.  It has a burgundy coloured ‘sport’ [called ‘Burgundy Ice’] which is genetically identical, but a pigment switch has been switched.  ‘Burgundy Ice’ is not completely stable and a shoot may ‘revert’ to ‘Iceberg’.  It puzzled geneticists for a long time that a ‘sport’ tends to ‘revert’ back to the original form far more often than to a new form.  Epigenetics explains that.

In technical terms the switches are often due to methylation of specific sections of gene associated DNA.  The methylation is copied with normal cell division so the position of the switch [on or off] can persist through growth.

If ipoc forms are less stable in twin-scaling, especially in the bulbils produced from higher up the scale, it suggests that the ipoc variation may be from a single gene, and one where the switch is unstable or prone to epigenetic variation.

I think the yellowness of Lady Elphinstone is so capricious that it must be multifactorial.  This year all of mine are yellow [about 15 blooms] and last year they were all green.  Some years they are mixed.  I can’t pin it down to maturity, weather or culture.

Chad.


Inland Cornwall

annew

  • Daff as a brush
  • Hero Member
  • *****
  • Posts: 5397
  • Country: england
    • Dryad Nursery: Bulbs and Botanic Cards
Re: Chipping-induced instability in snowdrops
« Reply #27 on: February 24, 2015, 06:06:02 PM »
Thank you Chad, I like the sound of that. I had a feeling methylation/ gene switching was involved but didn't know why it should occur more often in some morphs than others. The single gene theory sounds plausible.
MINIONS! I need more minions!
Anne Wright, Dryad Nursery, Yorkshire, England

www.dryad-home.co.uk

Susan Band

  • Hero Member
  • *****
  • Posts: 842
  • Country: 00
    • Pitcairn Alpines
Re: Chipping-induced instability in snowdrops
« Reply #28 on: March 02, 2015, 08:21:21 PM »
Thinking about colour instability. Does anyone else remember cutting different coloured Hyacinths in half, tying them together and getting two coloured flowers. I Vaguely
remember doing this as a child.
Susan Band, Pitcairn Alpines, ,PERTH. Scotland


Susan's website:
http://www.pitcairnalpines.co.uk

Maggi Young

  • Forum Dogsbody
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 44564
  • Country: scotland
  • "There's often a clue"
    • International Rock Gardener e-magazine
Re: Chipping-induced instability in snowdrops
« Reply #29 on: March 02, 2015, 08:27:37 PM »
You mean cutting the hyacinth bulbs in half and tying them together, Susan?

I've never heard of that and Ian says he doesn't either. Of course we both remember growing hyacinths in those cute vases - or jam jars ( I'll let you guess who used what ) with the bulb just above the water and the roots growing in water.
« Last Edit: March 02, 2015, 08:29:18 PM by Maggi Young »
Margaret Young in Aberdeen, North East Scotland Zone 7 -ish!

Editor: International Rock Gardener e-magazine

 


Scottish Rock Garden Club is a Charity registered with Scottish Charity Regulator (OSCR): SC000942
SimplePortal 2.3.5 © 2008-2012, SimplePortal