Northumberland Diary Discussion: 26 January 2014
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Leaf chloroplast variegation. Number 262.Go to latest contribution by John Good, 01 February 2014, 17:08. Go to bottom of this page.
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John - that really is good fun, and gets those grey cells ticking over again and sometimes for the first time. That picture of the helleborine is remarkable and fascinating. The one nurseryman who can return the favour is Joe Sharman, who has always grown and distributed many variegated plants (especially perennials) and gives talks on the same subject. Examples like the variegated forms of Eryngium planum are frustrating to propagate because they come green from root cuttings and albino from seed and usually die from division (and few of us have microprop, facilities!). The various curious forms of flowers (for example some of the woodland anemones), are equally fascinating and educative and oddly appealing to the gardener (though I have yet to collect any of the 'spiky' snowdrops!).
Thanks john, an excellent bit of education for a miserable Sunday evening
Might that variegated bamboo be Pleioblastus viridistriatus ? It's quite a short variety.
Yes Maggi, but the blessed Debbie Harry is American, and spells it 'Blondie', which is what I was trying to say!
Goodness me, I am quite sure there is nothing mutated about Ms Harry!!
What did you tjink of my bammboo suggestion?
Sorry for awful typing!
No idea I fear; don't have the relevant books. I expect you are right.
All very interesting!
Any thoughts on cyclamen leaf variegation, which seems to be a surface effect (as does pulmonaria)? The former is nearly symmetric following the veins, the other random.
This one (Galeobdolon) is very vigorous with all sorts of variegation and of course is best avoided.
Perhaps I should have said that there is a difference between variegated leaves and patterned leaves such the the cyclamen and lamiastrum you mention. As I said, variegated leaves are caused by mutations to chlorophyll-forming genes in the chloroplast DNA which are confined to either L11 or L111. They are not 'normal', but occur by accident and have been selected by horticulturalists for propagation.
Patterned leaves are 'normal', that is to say that they have been evolutionarily selected for some reason (e.g. crypsis, protection from herbivores, light gathering, leaf temperature control) and are typical of the species. They are rarely caused by mutations to chloroplast genes, but result from e.g. air spaces in the leaf, distribution of anthocyanin pigments (which may be layer-limited as are chloroplast variegations), light-reflecting epidermal cells, and other structural phenomena. They are interesting, and rather little studied, but they are not chlorophyll variegations.
I've just been putting together a talk on woodland plants, so many of which have this sort of leaf patterning - and one of the loveliest features of them for the way they can be used in shady parts of the garden. A good example is Brunnera macrophylla. The recent silvery forms like 'Jack Frost' come true from seed (with some variation as you would expect), whilst the attractive 'Hadspen Cream' is annoyingly prone to revert and disappear from the garden, and often resentful of division. Then there are plants like the variegated honesty, which again will breed true in the absence of green plants; but once you have this you want the rarer white flowered selection! This is quite an interesting subject.
Thanks, John, for a very lucid explanation (for a botanist at least!) of the intricacies of the mecahnisms determining different forms of variegation. I always continue to say that I learn something new every day, and much of what you have written here fits that bill for today.