I received the following from an author in New Zealand. Maybe some of you can
give a more definite answer.
From
I am a New Zealand novelist and my third novel is
about to be published. In it I refer to a graft hybrid citrus
tree created by one of my characters, an American
orange-grower of the 1890s. He creates a tree that
produces both oranges and lemons. I am very much
hoping you might be able to tell me whether, in theory,
this is possible!
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

I once met somebody who told me of a Citrus tree in Russia which was full of
grafts. The keepers of this tree had a policy of asking visitors to bring a
stick of their favourite Citrus tree: this was grafted onto the tree. The
trick was to get the tree to produce as many different Citrus fruits as
possible.

All commercial Citrusfruits are hybrids going back to three (four?) species
so they are quite compatible. I would say it is more than possible.
PvR


Iris Cohen schreef
I received the following from an author in New Zealand. Maybe some of you
can give a more definite answer.

From
I am a New Zealand novelist and my third novel is
about to be published. In it I refer to a graft hybrid citrus
tree created by one of my characters, an American
orange-grower of the 1890s. He creates a tree that
produces both oranges and lemons. I am very much
hoping you might be able to tell me whether, in theory,
this is possible!
Iris,

A true graft hybrid is a plant that has genetic material from both
parents in all cells and which has arisen from cells right at the
graft union. True graft hybrids are very rare, because you have to get
actual mixing of cell contents and then development of a shoot from
these mixed cells. I don't know if lemons and oranges would do this.
IF it happened, the resulting hybrid would bear something intermediate
between an orange or a lemon, not oranges AND lemons.

BUT, citrus varieties and species are often widely compatible as
grafting scions and stocks, so it would be possible to have a whole
tree full of, say, different orange varieties. Not sure if oranges
and lemons are compatible as scion and stock, but I'd bet both are
graftable to trifoliate orange, which is widely used as a stock for
citrus. If they are, then you could have a tree that bears both
oranges and lemons. A bit of research from your author should turn up
whether both share a compatible stock and if so, when it was first
use--and make sure that the horticultural terms used in the book are
accurate.

Monique Reed

Iris Cohen wrote:

I received the following from an author in New Zealand. Maybe some of you can
give a more definite answer.
From
I am a New Zealand novelist and my third novel is
about to be published. In it I refer to a graft hybrid citrus
tree created by one of my characters, an American
orange-grower of the 1890s. He creates a tree that
produces both oranges and lemons. I am very much
hoping you might be able to tell me whether, in theory,
this is possible!
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

Oranges, lemons, and virtually all other citrus varieties are freely
graft-compatible, so yes, such a tree could be made. Monique is right that
what you'd have is NOT a graft hybrid, however. There are a couple known true
graft chimeras in the citrus world -- 'Natsudaidai' from Japan comes to mind,
which produces a mandarin orange fruit surrounded by a grapefruit peel, but
even there, you have different genotypes in the L1, L2, and/or L3 developmental
layers of cells, not a true blending of genetic material within any one cell.

Dr. Jude Grosser, at the University of Florida Citrus Research Center in Lake
Alfred, has made somatic hybrids, in which 2 cells are fused together under
tissue culture conditions, and the resulting plant has the complete genetic
complement of each "parent." He has, for example, 'Key' lime x 'Hamlin' sweet
orange and 'Key' lime x Poncirus trifoliata somatic hybrids. The trees are
intermediate between the parents, and tend to be rather compact growers since
they are 4N. But of course, these are not "graft" hybrids, since a graft is
not involved (unless you consider protoplast fusion to be a form of grafting; I
do not.)

In article , wrote...

A true graft hybrid is a plant that has genetic material from both
parents in all cells and which has arisen from cells right at the
graft union. True graft hybrids are very rare, because you have to get
actual mixing of cell contents and then development of a shoot from
these mixed cells.

Ummm, I don't think that's accurate. As I recall it, "graft hybrids"
are just chimeras, with tissues composed of a mix of cells of both the
stock and scion of the original graft union. The cells don't actually
fuse, but both cell types take part in the same growing tips that
produce the shoots, leaves, flowers, etc. of the "hybrid".

Such periclinal chimeras in angiosperms can be quite stable [forming
shoots with outer tissues from one "parent" over inner tissues of the
other], and graft hybrids will sometimes arise as adventitious buds
formed from the graft union tissues. It can be possible to destroy all
the lateral buds on a grafted plant, cut it off through the graft union,
and get "graft hybrid" shoots regenerating from callus formed from the
graft union region.

Hybrids formed by somatic cell fusions such as you describe are also
possible [especially in laboratory cell cultures], but they're
a separate thing from "graft hybrids".

http://www.universaldbase.com/cshs/a...posium_S20.pdf

I don't know if lemons and oranges would do this.
IF it happened, the resulting hybrid would bear something intermediate
between an orange or a lemon, not oranges AND lemons.

A true "graft hybrid" here might have epidermal tissues of one species
over internal tissue of the other. [But would the rind and the pulp
vesicles both be of epidermal origin?]

BUT, citrus varieties and species are often widely compatible as
grafting scions and stocks,

Not only that, but they're also graft-compatible with species of
related genera, such as kumquats [Fortunella] and trifoliate orange
[Poncirus].

so it would be possible to have a whole
tree full of, say, different orange varieties. Not sure if oranges
and lemons are compatible as scion and stock, but I'd bet both are
graftable to trifoliate orange, which is widely used as a stock for
citrus. If they are, then you could have a tree that bears both
oranges and lemons.

I've little doubt one might also graft limes and grapefruits and
mandarins onto a single tree along with the oranges and lemons.

For that matter, Citrus and kin are also widely hybridizable in the
usual sexual way [including with Poncirus and Fortunella]. Some
intergeneric hybrids are being used as grafting stocks.

http://www.lal.ufl.edu/castle/Abstracts.html
http://www.lal.ufl.edu/castle/citation.html
http://www.fcprac.ifas.ufl.edu/citru...rootstocks.htm
http://edis.ifas.ufl.edu/XC004
http://www-horticulture.tamu.edu/citrus/l2304.htm

[snip]

cheers

Shows you how long it's been since I took Plant Propagation. I think
there are some non-chimeric graft hybrids known among walnuts; that's
what I was remembering.

Monique

mel turner wrote:

In article , wrote...

A true graft hybrid is a plant that has genetic material from both
parents in all cells and which has arisen from cells right at the
graft union. True graft hybrids are very rare, because you have to get
actual mixing of cell contents and then development of a shoot from
these mixed cells.

Ummm, I don't think that's accurate. As I recall it, "graft hybrids"
are just chimeras, with tissues composed of a mix of cells of both the
stock and scion of the original graft union. The cells don't actually
fuse, but both cell types take part in the same growing tips that
produce the shoots, leaves, flowers, etc. of the "hybrid".

Such periclinal chimeras in angiosperms can be quite stable [forming
shoots with outer tissues from one "parent" over inner tissues of the
other], and graft hybrids will sometimes arise as adventitious buds
formed from the graft union tissues. It can be possible to destroy all
the lateral buds on a grafted plant, cut it off through the graft union,
and get "graft hybrid" shoots regenerating from callus formed from the
graft union region.

Hybrids formed by somatic cell fusions such as you describe are also
possible [especially in laboratory cell cultures], but they're
a separate thing from "graft hybrids".

http://www.universaldbase.com/cshs/a...posium_S20.pdf

I don't know if lemons and oranges would do this.
IF it happened, the resulting hybrid would bear something intermediate
between an orange or a lemon, not oranges AND lemons.

A true "graft hybrid" here might have epidermal tissues of one species
over internal tissue of the other. [But would the rind and the pulp
vesicles both be of epidermal origin?]

BUT, citrus varieties and species are often widely compatible as
grafting scions and stocks,

Not only that, but they're also graft-compatible with species of
related genera, such as kumquats [Fortunella] and trifoliate orange
[Poncirus].

so it would be possible to have a whole
tree full of, say, different orange varieties. Not sure if oranges
and lemons are compatible as scion and stock, but I'd bet both are
graftable to trifoliate orange, which is widely used as a stock for
citrus. If they are, then you could have a tree that bears both
oranges and lemons.

I've little doubt one might also graft limes and grapefruits and
mandarins onto a single tree along with the oranges and lemons.

For that matter, Citrus and kin are also widely hybridizable in the
usual sexual way [including with Poncirus and Fortunella]. Some
intergeneric hybrids are being used as grafting stocks.

http://www.lal.ufl.edu/castle/Abstracts.html
http://www.lal.ufl.edu/castle/citation.html
http://www.fcprac.ifas.ufl.edu/citru...rootstocks.htm
http://edis.ifas.ufl.edu/XC004
http://www-horticulture.tamu.edu/citrus/l2304.htm

[snip]

cheers

In article , mel turner mturner@sni
pthis.acpub.duke.edu writes
In article ,
wrote...

A true graft hybrid is a plant that has genetic material from both
parents in all cells and which has arisen from cells right at the
graft union. True graft hybrids are very rare, because you have to get
actual mixing of cell contents and then development of a shoot from
these mixed cells.

Ummm, I don't think that's accurate. As I recall it, "graft hybrids"
are just chimeras, with tissues composed of a mix of cells of both the
stock and scion of the original graft union. The cells don't actually
fuse, but both cell types take part in the same growing tips that
produce the shoots, leaves, flowers, etc. of the "hybrid".

Such periclinal chimeras in angiosperms can be quite stable [forming
shoots with outer tissues from one "parent" over inner tissues of the
other], and graft hybrids will sometimes arise as adventitious buds
formed from the graft union tissues. It can be possible to destroy all
the lateral buds on a grafted plant, cut it off through the graft union,
and get "graft hybrid" shoots regenerating from callus formed from the
graft union region.

Hybrids formed by somatic cell fusions such as you describe are also
possible [especially in laboratory cell cultures], but they're
a separate thing from "graft hybrids".

I was also of the opinion that graft hybrids and chimeras were the same,
but I was recently browsing a book which had them as different. It
appears that the original hypothesis for various plants
(Hawthorn/Medlar, Laburnum/Broom) now recognised as chimeras was that
they were true hybrids arising from fusion of cells in the graft, and
therefore described as "graft hybrids". It would appear that there are
two usages for the term "graft hybrid". (And checking B. Daydon
Jackson's "A Glossary of Botanic Terms" I find a 3rd - "effect produced
by one or other of the united individuals on its grafted fellow" - which
would seem to make a fruit tree on a dwarfing rootstock a "graft
hybrid".)
--
Stewart Robert Hinsley

Stewart Robert Hinsley
Hybrids formed by somatic cell fusions such as you describe are also
possible [especially in laboratory cell cultures], but they're
a separate thing from "graft hybrids".

+ + +
cytohybrids?
+ + +

I was also of the opinion that graft hybrids and chimeras were the same,
but I was recently browsing a book which had them as different. It
appears that the original hypothesis for various plants
(Hawthorn/Medlar, Laburnum/Broom) now recognised as chimeras was that they
were true hybrids arising from fusion of cells in the graft, and
therefore described as "graft hybrids". It would appear that there are
two usages for the term "graft hybrid". (And checking B. Daydon
Jackson's "A Glossary of Botanic Terms" I find a 3rd - "effect produced
by one or other of the united individuals on its grafted fellow" - which
would seem to make a fruit tree on a dwarfing rootstock a "graft
hybrid".)
--
Stewart Robert Hinsley

+ + +
I would suppose that this is why the ICNCP uses "graft-chimaera" as the
official term?
PvR

I don't know about citrus, but I did this with geraniums once, so having
different colours and leaf types on the one plant.
Or maybe they were pelargoniums.




"Iris Cohen" wrote in message
...
I received the following from an author in New Zealand. Maybe some of you
can
give a more definite answer.
From
I am a New Zealand novelist and my third novel is
about to be published. In it I refer to a graft hybrid citrus
tree created by one of my characters, an American
orange-grower of the 1890s. He creates a tree that
produces both oranges and lemons. I am very much
hoping you might be able to tell me whether, in theory,
this is possible!
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

Last My a field of lemon trees was skin-grafted with navel oranges, and it
will be producing oranges in two years
..
A bergamoto, has be grafted to produce large fruits.

Clementins without seeds have to be repoduced by grafting (normally). A
citrus tree should be grafted in crescent moon, April or May.

In a fig tree grafted with four kinds of figs the correct order is: early
breed (early producing should be in the east side of the tree, and late
crops in the west side, here is a fig tree grafted with more than six knd of
figs,which means it has figs from July to Novembre. The grating of a fig in
skin in June, and by "samples" in January...

Eventually the stronger breed, if not taken care, with "kill" the others
since it will request more from the "foot".

In a bonsai magazine, a few month ago there was an article on how to graft
pine trees, of course with pictures. Next year I will be experimenting with
pines



"Iris Cohen" escribió en el mensaje
...
I received the following from an author in New Zealand. Maybe some of you
can
give a more definite answer.
From
I am a New Zealand novelist and my third novel is
about to be published. In it I refer to a graft hybrid citrus
tree created by one of my characters, an American
orange-grower of the 1890s. He creates a tree that
produces both oranges and lemons. I am very much
hoping you might be able to tell me whether, in theory,
this is possible!
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)

In article ,
wrote...
In article , mel turner mturner@sni
pthis.acpub.duke.edu writes
In article ,
wrote...

A true graft hybrid is a plant that has genetic material from both
parents in all cells and which has arisen from cells right at the
graft union. True graft hybrids are very rare, because you have to get
actual mixing of cell contents and then development of a shoot from
these mixed cells.

Ummm, I don't think that's accurate. As I recall it, "graft hybrids"
are just chimeras, with tissues composed of a mix of cells of both the
stock and scion of the original graft union. The cells don't actually
fuse, but both cell types take part in the same growing tips that
produce the shoots, leaves, flowers, etc. of the "hybrid".

Such periclinal chimeras in angiosperms can be quite stable [forming
shoots with outer tissues from one "parent" over inner tissues of the
other], and graft hybrids will sometimes arise as adventitious buds
formed from the graft union tissues. It can be possible to destroy all
the lateral buds on a grafted plant, cut it off through the graft union,
and get "graft hybrid" shoots regenerating from callus formed from the
graft union region.

Hybrids formed by somatic cell fusions such as you describe are also
possible [especially in laboratory cell cultures], but they're
a separate thing from "graft hybrids".

I was also of the opinion that graft hybrids and chimeras were the same,
but I was recently browsing a book which had them as different.

Interesting. What is the distinction? Do non-chimera graft
hybrids actually exist, or are they just hypothetical?

It
appears that the original hypothesis for various plants
(Hawthorn/Medlar, Laburnum/Broom) now recognised as chimeras was that
they were true hybrids arising from fusion of cells in the graft, and
therefore described as "graft hybrids".

Okay, but that original hypothesis was incorrect, and "graft
hybrids" all turned out to be chimeras, right? Or, if this is not
the case, what are some examples of "genuine graft-hybrids"? [I
suppose somatic hybrids formed by protoplast fusions and using modern
cell culture techaniques could count, but they're not derived from
"grafts" in the usual sense].

It would appear that there are
two usages for the term "graft hybrid". (And checking B. Daydon
Jackson's "A Glossary of Botanic Terms" I find a 3rd - "effect produced
by one or other of the united individuals on its grafted fellow" - which
would seem to make a fruit tree on a dwarfing rootstock a "graft
hybrid".)

Again, interesting.

Okay, I'll have to look a bit further on this.

A web search found this post [to an orchid list] which also says
graft hybrids and chimeras are different [but didn't say how]. It
also gives a number of references::

ttp://www.potto-webdesign.com/mailman/public/orchids/2003-April/001448.html

[begin quote]

[OGD] Graft hybridization

Hideka Kobayashi hkobayashi4 at yahoo.com
Tue Apr 22 18:01:40 CEST 2003

There is no interchange of genetic material.

I guess you didn't understand. Although there is no
exchange of genetic material, short pieces of RNA can
travel through graft or scion, and can interfere
expression of traits, etc. Yes, this can be heritable.
It's called RNAi (RNA interference). The most recent
Nobel Prize (in medicine?) recepients were recognized
for their studies on RNAi in C. elegans, etc.

These plants are properly called graft chimaeras.

Graft chimeras and graft hybrids are not strictly the
same. They are often mixed or confused, though.

As far as I know, the only documented ones are woody
plants.

Not so. Could you define "documented"?

From a simple search with Agricola:

AU: Hirata,-Y.; Motegi,-T.; Takeda,-Y.; Morikawa,-K.
TI: Induction of cytoplasmic male sterility in the
seed progeny derived from artificially-synthesized
interspecific chimera in Brassica.
SO: Euphytica. Dordrecht : Kluwer Academic Publishers.
2001. v. 117 (2) p. 143-149.

AU: Hirate [sic],-Y.; Noguchi,-T.; Oguni,-S.; Kan,-T.
TI: Genetic constitution of germ cells in
intervarietal and interspecific chimeras on Brassica
induced by in-vitro grafting.
SO: Theor-appl-genet. Berlin, W. Ger. : Springer
International. Oct 1994. v. 89 (2/3) p. 249-254.

AU: Hamaguchi,-H.; Kokubun,-M.; Yoneyama,-T.;
Hansen,-A.P.; Akao,-S.
TI: Control of supernodulation in intergeneric grafts
of soybeans and common beans.
SO: Crop-sci. Madison, Wis. : Crop Science Society of
America, 1961-. July/Aug 1993. v. 33 (4) p. 794-797.

AU: Kaddoura,-R.L.; Mantell,-S.H.
TI: Synthesis and characterization of
Nicotiana-Solanum graft chimeras.
SO: Ann-Bot. London : Academic Press. Dec 1991. v. 68
(6) p. 547-556.

AU: Noguchi,-T.; Hirata,-Y.; Yagishita,-N.
TI: Intervarietal and interspecific chimera formation
by in vitro graft-culture method in Brassica.
SO: Theor-Appl-Genet. Berlin, W. Ger. : Springer
International. 1992. v. 83 (6/7) p. 727-732.

AU: Sharkoff,-J.; Brick,-M.A.
TI: Effects of grafting roots and shoots of Phaseolus
vulgaris and P. acutifolius on physiological and
morphological variables.
SO: Annu-Rep-Bean-Improv-Coop. Fort Collins, Colo :
Howard F. Schwartz, Colorado State University. 1990.
v. 33 p. 190-191.

AU: Gordon-Weeks,-R.; White,-R.F.; Pierpoint,-W.S.
TI: Evidence for the presence of endogenous inducers
of the accumulation of pathogenesis-related (PR-1)
proteins in leaves of virus-infected tobacco plants
and of an interspecific Nicotiana hybrid.
SO: Physiol-Mol-Plant-Pathol. London : Academic Press.
May 1991. v. 38 (5) p. 375-392.

AU: Lee,-S.H.; Ashley,-D.A.; Boerma,-H.R.
TI: Regulation of nodule development in
supernodulating mutants and wild-type soybean.
SO: Crop-Sci. Madison, Wis. : Crop Science Society of
America. May/June 1991. v. 31 (3) p. 688-693.

AU: Yagishita,-N.; Hirata,-Y.; Okochi,-K.; Mimura,-K.;
Mizukami,-H.; Ohashi,-H.
TI: Characterization of graft-induced change in
capsaicin content of Capsicum annuum L.
SO: Euphytica. Wageningen : Netherlands Study Circle
of Plant Breeding. Aug 1985. v. 34 (2) p. 297-301.
ill.

AU: Pandey,-K-K
TI: Genetic transformation and "Graft-hybridization"
in flowering plants [Tobacco]
SO: TAG-Theor-Appl-Genet, 1976, 47 (6): 299-302. Ref.

I found more in the past, but don't have time to do a
through search. Brassica, Phaseolus, Glycine, Tobacco,
etc are not woody plants.

If you try to reproduce it with seeds, you will only
get the genetic material from one species.

This is the case with simple chimeras like the one you
described. Not the ones I mentioned."

[end quote]

Some more less relevant results from a search of
Biological Abstracts:

Title: INTERGENERIC HYBRIDS BETWEEN CRATAEGUS AND MESPILUS A FRESH
LOOK AT AN OLD PROBLEM.
Author, Editor, Inventor: BYATT-J-I; FERGUSON-I-K; MURRAY-B-G
Source: Botanical-Journal-of-the-Linnean-Society. 1977; 74 (4):
329-344.
Abstract: A brief outline is given of the history and nomenclature of
the sexual and graft hybrids (chimeras) between Crataegus and Mespilus.
An investigation has been made of some aspects of the macromorphology,
the pollen fertility and exine characters, cytology and physiology of
the plants growing in the Royal Botanic Gardens, Kew [England]. It is
suggested that in the past too much emphasis has been laid on the
anatomy of the epidermal layers and the separation of parental
characters in chimeras. Observations made during the study show the
presence of intermediate characters in the graft hybrid
[+ Crataegomespilus] as well as in the sexual hybrid
[x Crataemespilus] and there is evidence that most parts of the graft
hybrids are probably influenced by both the parental genotypes.

Title: THE ALKALOID PATTERN OF THE GRAFT HYBRID LABURNOCYTISUS-ADAMII
FABACEAE.
Author, Editor, Inventor: GREINWALD-R {a}; WINK-M; WITTE-L; CZYGAN-F-C
Source: Biochemie-und-Physiologie-der-Pflanzen-BPP. 1991; 187 (5):
385-391.
Language: GERMAN
Abstract: The alkaloid pattern of the graft hybrid Laburnocytisus
adamii (Laburnum anagyroides + Cytisus purpureus) was analyzed by GC
and GC-MS. 14 alkaloids (mostly quinolizidine alkaloids, but also
bipiperidyl and pyrrolizidine alkaloids) were identified. Interesting
seaonal changes of the alkaloid pattern were observed in leaves. Leaf
buds accumulate the highest total alkaloid amount with more than 90%
cytisine. During the development of the leaves in spring, a substantial
increase of N-methylcytisine was observed. Later in the year, the
alkaloid concentration of the leaves strongly declined. The alkaloid
pattern did not reflect the hybrid status of Laburnocytisus adamii. It
was very close to that of Laburnum anagyroides, while the typical
alkaloids of Cytisus purpureus could not be detected. However,
remarkable quantitative differences were observed. The alkaloid content
of plant parts originating from Laburnum were as high as in Laburnum
anagyroides, whereas those originating from Cytisus were rather low.
Thus the hybrid status of this plant is both reflected in its
morphology and its content of quinolizidine alkaloids.

Title: Genetic mosaics and the analysis of leaf development.
Author, Editor, Inventor: Marcotrigiano-Michael {a}
Source: International-Journal-of-Plant-Sciences. [print] May, 2001;
162 (3): 513-525.
Abstract: Genetic mosaics with phenotypic markers can be used to study
the development of normal leaves. Mosaics synthesized between normal
cells and cells possessing developmental mutations can be used to
determine whether or not a mutation acts cell autonomously or if cell-
to-cell interactions occur. This article reviews the use of
cytochimeras, plastid chimeras, radiation-induced chimeras, and graft
chimeras to analyze leaf development in angiosperms and to gain insight
into the cell lineage, cell-to-cell communication, and the control of
morphology. New data are also presented. Leaves of plastid chimeras and
graft chimeras were analyzed to determine the level of cell autonomy
in different regions of the leaf blade. Evidence that small populations
of leaf cells can act out developmental programs is presented. The
relationship of these leaves to concepts such as developmental
compartments, organismal theory, and pattern formation is discussed.

Title: In vitro neoformation of grape chimeras (Vitis vinifera L.).
Author, Editor, Inventor: Verdisson-Sandrine {a}; Baillieul-F;
Audran-J-C
Source: Journal-International-des-Sciences-de-la-Vigne-et-du-Vin.
Jan.-Feb., 1999; 33 (1): 1-7.
Language: French; Non-English
Language of Summary: English; French
Abstract: Difference in grape sensitivity to Botrytis cinerea attacks
between cultivars was explained by differences in the epidermic tissue
of the fruit Therefore, this work was conducted to create a grape
periclinal chimera, whose fruits would combine the skin of a Botrytis
tolerant cultivar with a pulp of an another cultivar admitted its good
organoleptic quality and productivity. In a first time, graftings of
two cultivars (Chardonnay and Pinot noir) were conducted in vitro on
5 different media supplemented with various plant growth regulators.
Adventitious shoots were only observed on medium containing BAP and
GA3 from a mixed callus structure after four weeks of darkness followed
by a light/dark regime. In a second time, RAPD analysis, conducted on
these plants, showed their chimerical characteristics.

Title: Graft chimeras and somatic hybrids of new cultivars.
Author, Editor, Inventor: Lindsay-G-C {a}; Hopping-M-E; Binding-H;
Burge-G-K
Source: New-Zealand-Journal-of-Botany. 1995; 33 (1) 79-92.
Abstract: Three techniques were evaluated as methods for plant
improvement: protoplast fusion in vitro for somatic hybrids,
protoplast co-culture in vitro for chimeras, and graft manipulation in
planta for periclinal chimeras. Methods were developed initially for
herbaceous, solanaceous species and then evaluated on two species of
woody Actinidia. Protoplasts from tomato (2n = 24) and BU (a Solanum
hybrid obtained by fusing nightshade and dihaploid potato protoplasts,
2n = 96) were fused at laboratories located at Kiel, Germany, and
Levin, New Zealand. Identical methods were used at each laboratory,
and plants were regenerated from the hybrid callus. At Kiel, only
1.6% of the regenerants were symmetric fusions that contained 120
chromosomes. One chimeric plant remained genomically stable during 3
years of in vitro growth and a further year in the glasshouse. At
Levin, 83% of regenerants were asymmetric fusions with additional
nightshade or Bu genomes. Some regenerants, however, contained a
single nightshade genome. Protoplasts from Actinidia were fused using
the methods detailed for the solanaceous plants, but regeneration of
plants was not achieved. Chimeric plants were obtained by co-culturing
Bu and tomato plants. At Kiel, 2.1% of the regenerants were chimeric.
Co-cultures of protoplasts between Actinidia arguta and A. deliciosa,
at Levin, did not produce regenerative callus. Periclinal chimeras
were sought from in planta grafts between tomato and nightshade. Two
chimeric shoots were obtained. On the basis of epidermal hair type,
pollen compatibility, seed and fruit set, one chimera had the
histogenic LI layer of nightshade over LII and LIII histogenic layers
of tomato (NTT), and the other had two layers of nightshade over one
layer of tomato (NNT). Chimera NTT was more stable than NNT, but both
produced axillary shoots with characteristics of the other chimera.
Periclinal chimeras were also sought from graft unions in planta and
in vitro between A. arguta and A.deliciosa. From in planta grafts, all
adventitious shoots were A. arguta. From in vitro grafts, 75% of the
shoots that regenerated were A. deliciosa and none was chimeric. Each
of these techniques has the potential to produce new plants. However,
the probability of success was low and therefore a large number of
regenerants would be required from which to select the desired plants.

Title: Arrangement of cell layers in the shoot apical meristems of
periclinal chimeras influences cell fate.
Author, Editor, Inventor: Marcotrigiano-Michael {a}; Bernatzky-Robert
Source: Plant-Journal. 1995; 7 (2) 193-202.
Abstract: Utilizing a complete set of six periclinal graft chimeras
composed of Nicotiana tabacum and Nicotiana glauca (TGG, GTT, TTG, GGT,
TGT, and GTG), the fate of the three apical cell layers in both
vegetative and reproductive organs has been traced. An analysis of
leaf phenotype indicated that only rarely did deviations from expected
cell lineage occur and in only TTG did such deviations originate in
the shoot apical meristem rather than during leaf development. In most
plants that possess a stratified shoot apical meristem, gametes are
derived from the second apical layer (L2). A phenotypic and/or DNA
analysis of seed progeny following reciprocal crosses between all
chimeras and their component species indicated that pollen and eggs
were sometimes derived from non-L2 lineage in all but one periclinal
chimera. There was no evidence for non-L2-derived gametes in 95 crosses
where GTT was a parent whereas 40 of 104 crosses with TTG as a parent
yielded some offspring that resulted from non-L2-derived gametes. Of
these 40 cases, non-L2-derived pollen grains were responsible 39 times
while non-L2-derived eggs were responsible just once. Therefore, the
occurrence of non-L2-derived gametes was not random. The disruption of
'normal' lineage patterns was dependent on the specific arrangement of
genetically dissimilar tissue layers in the shoot apices of the
chimeras and was different for different organs.

Interestingly enough, Citrus grafts come back into the pictu

Title: Interactions between different genotypic tissues in citrus
graft chimeras.
Author, Editor, Inventor: Zhou-Jinmei; Hirata-Yutaka {a}; Nou-Ill-Sup;
Shiotani-Hiroshi; Ito-Tsutau
Source: Euphytica-. [print] 2002; 126 (3): 355-364.
Abstract: Citrus chimeras NFF (layer constitution: L1-L2-L3=NFF) and
FNN (layer constitution L1-L2-L3=FNN) were periclinal chimeras,
produced by grafting of Citrus sinensis cv. Fukuhara orange (F) and
C. natsudaiddai cv. Kawano natsudaidai (N). Some characters of F or N,
such as the color of epicarp and juice sacs of fruits, developed
independently in their chimeras, while other characteristics,
including leaf size and stoma size, sugar content, acidity and size
of the fruits in the chimeras displayed interactions between the two
genetically different tissues, i.e., the 'exogenous' epidermis (L1)
in the chimeras imposed effect on the quantitative characters that
were inner tissue derived or determined of making them oriented to
those of its (L1) donor plant. So did the inner tissues to the
L1-determined or derived traits. Cell displacement occurred during
leaf development in the NFF chimera and cell replacement in both
chimeras occurred during fruit development. Peroxidase analysis
revealed that each donor plant had one unique band. The N-peroxidase
band was stably detected in both chimeras. This band could thus be
used as a reliable marker of N tissue in chimeric plants. No chimera
specific isozyme band was detected. RAPD analysis, however, showed the
presence of chimera specific bands besides the donor specific bands.
This suggests that interactions between genotypically different cells
caused variation(s) at the DNA level, and thus could be a source of
genetic variation(s).

Title: Histogenic identification by RAPD analysis of leaves and fruit
of newly synthesized chimeric Citrus.
Author, Editor, Inventor: Sugawara-Kuniaki {a}; Wakizuka-Takumi {a};
Oowada-Atsushi {a}; Moriguchi-Takaya; Omura-Mitsuo
Source: Journal-of-the-American-Society-for-Horticultural-Science.
[print] January, 2002; 127 (1): 104-107.
Abstract: Randomly amplified polymorphic DNA (RAPD) analysis was used
to investigate the histogenic structure of leaf and fruit tissues in
four graft chimeras, two intentional chimeras that were produced in
combination with 'Hamlin' orange (Citrus sinensis (L.) Osbeck) and
'Satsuma' mandarin (C. unshiu Marc.), and two naturally occurring
periclinal chimera cultivars, Kobayashi Mikan (a graft chimera of C.
unshiu and C. natsudaidai Hayata), and Kinkoji Unshu (a graft chimera
of C. unshiu and C. obovoidea hort. ex Takahashi). RAPD profiles of
the lamina epidermis and the mesophyll cells of specific individuals
indicated that the four graft chimeras were interspecific monekto
chimeras, whose outermost layer (histogenic layer L-1) of the shoot
apical meristem consisted of a species that was different from that in
the inner layers (histogenic layers L-2 and L-3). Moreover, juice
vesicles, which develop from the inside cells of the pericarp and
become the main edible parts of Citrus fruit, were a mixture of the
cells from both parental source cultivars. Therefore, the vesicles
were at least composed of L-1 and subepidermal inner L-2 cells. This
determination of interspecific chimeral construction (which was made
possible by molecular techniques) is a valuable finding, in terms of
improving Citrus through intentional use of periclinal chimerism.

Title: Arising of the intermediated forms by grafting subfamily
Aurantioideae.
Author, Editor, Inventor: Kapanadze-I-S {a}; Kapanadze-B-I
Source: Doklady-Akademii-Nauk. Sept., 1997; 356 (2) 278-279.
Language: Russian; Non-English
Major Concepts: Horticulture- (Agriculture-)
Super Taxa: Rutaceae-: Dicotyledones-, Angiospermae-, Spermatophyta-,
Plantae- Organisms: Atalantia-monophylla (Rutaceae-): fruit-crop;
Citrus-unshiu (Rutaceae-): fruit-crop; Eremocitrus-glauca (Rutaceae-):
fruit-crop; Fortunella-japonica (Rutaceae-): fruit-crop;
Microcitrus-excelsa (Rutaceae-): fruit-crop; Poncirus-ichangensis
(Rutaceae-): fruit-crop; Poncirus-trifoliata (Rutaceae-): fruit-crop
Taxa Notes: Angiosperms-; Dicots-; Plants-; Spermatophytes-;
Vascular-Plants Parts, Structures and Systems of Organisms: phloem-;
xylem- Miscellaneous Descriptors: chimera-type; grafting-;
intermediate-Aurantioideae-forms

http://www.serendipityrancher.com/citrusfruits.htm:

"A curious aspect of citrus plants is provided by the so-called
"freaks," first observed in a Florentine garden in 1640. These citrus
plants whose leaves, flowers, and fruits have characteristics varying
between the orange and the lemon: lemons with orange skins or vice
versa, alternate segments of orange or of lemon. They are "chimeras"
or graft hybrids in which there is a kind of fusion of the tissues of
the two species. [Bianchini, Francesco, Corbetta, Francesco, Pistoia,
Marilena, The Complete Book of Fruits and Vegetables, United States
Translation: Crown Publishers, New York, 1976; Originally published
in Italy as I Frutti della Terra, Arnoldo Mondadori Publisher, Italy,
1973]"

http://www.habitas.org.uk/gardenflora/taxa.htm#Graft
http://aggie-horticulture.tamu.edu/t...s/chimera.html
http://nucleus.cshl.org/worldpac/eng/slinks/s000856.htm

It seems that hypotheses of genetic transformation by
graft-hybridization reportedly played a role in the
Lysenkoism debacle in the USSR.

http://www.wayofscience.info/unit3part8.html:

"Setting the stage for Lysenko was another curious figure of the time,
Michurin. He was a minor landowner, and a fanatic believer in his own
cockeyed ideas about agriculture (i.e., he was a classic "crank"). He
was convinced that the scientific "establishment" was too closed-minded
to listen to his grand and revolutionary ideas. One of these was graft
hybridization, which he said was a speedy way of improving fruit crops.
This idea says that, for example, if a branch of a good-fruited but
temperature-sensitive apple is grafted onto a poor-fruited but hardy
rootstock tree, the seeds produced by the branch will somehow inherit
the hardiness from the rootstock. This situation is analogous to saying
that a Chinese person getting a kidney transplant from a black African
will give rise to dark-skinned children. With what you already know
about DNA and genes, it should be clear that the branch (or person)
will produce offspring genetically unaffected by the graft. Michurin
claimed to have overwhelming evidence for graft hybridization, and
impoverished himself privately publishing his great works (since the
"establishment" would not). Unfortunately, it was quite apparent to
the "establishment" that Michurin had no idea how to do properly
controlled experiments.

Michurin set the stage for Lysenko, but the two differed greatly.
Michurin was a crank, a true believer. Lysenko was a charlatan, a
power-hungry anti-intellectual fraud."

http://www.comms.dcu.ie/sheehanh/lysenko.htm
http://www.human-nature.com/rmyoung/papers/getting.html

Darwin also had some comments on "graft hybrids":

http://pages.britishlibrary.net/char...riation11.html

I get the impression that the whole "graft hybrids" hypothesis
reflected vague, pre-modern-genetics notions of heritability, and
were supplanted by the "graft-chimera" explanation.

cheers

I get the impression that the whole "graft hybrids" hypothesis
reflected vague, pre-modern-genetics notions of heritability, and
were supplanted by the "graft-chimera" explanation.

cheers

+ + +
Interesting. Apparently there are some effects by one component of a chimera
on the other, but they are not very major or they would be more prominent in
the public eye, to say nothing of the literature, grafting being as popular
as it is.
PvR

Note the discussion on xenotransplants.

In article , P van
Rijckevorsel writes
Interesting. Apparently there are some effects by one component of a chimera
on the other, but they are not very major or they would be more prominent in
the public eye, to say nothing of the literature, grafting being as popular
as it is.

The following is speculation.

Many plants have 3 layers of tissue in the meristem.

Lavatera x clementii 'Rosea' is non-chimaeric, and has rose-coloured
petals with a rose-red eye. Let us denote the composition of the 3
layers in this cultivar as RRR.

Lavatera x clementii 'Barnsley', to the best of my knowledge, is a sport
of 'Rosea'. It has flowers that open white, with the same rose-red eye.
The flowers turn pink as the age. It is known to be a periclinal
chimaera, and also is observed to have a propensity to revert to a rose-
flowered state. Let conjecture, for reasons which should become clear,
that the composition of the 3 layers is WRR.

Lavatera x clementii 'Blushing Bride', to the best of my knowledge, is a
sport of 'Barnsley'. The flowers age to a slightly paler pink than
'Barnsley', and it does not have the same tendency to revert. (I've seen
one source that says that this variety to not change colour as it ages,
but consider the cultivar name, I'm confident that that source is in
error.) I conjecture that this is WWR.

There are cultivars with similar flowers which don't turn pink with age,
which would be WWW. 'Lisanne' is, I believe, a cross between Lavatera
thuringiaca 'Ice Cool' (which has pure white flowers, including the eye)
and 'Barnsley' - I have been told that it's a sport of 'Barnsley', but
the habit differs, and is similar to the supposed seed parent, so I find
that explanation more convincing. 'Memories' (aka 'Stelav') also has a
compact habit, and may be a similar cross.

It may be the case that the aging to pink is an effect of the R genotype
on W genotype tissue.

Lavatera x clementii 'Candy Floss' ('Cotton Candy' from some US
suppliers) has a colour pattern very similar to 'Rosea' (perhaps a
fraction paler), but has a herbaceous habit, and differently shaped
flowers. It seems to me that this is a similar cross, but with 'Rosea'
as the parent instead of 'Barnsley', and perhaps wild-type thuringiaca
rather than 'Ice Cool'.
--
Stewart Robert Hinsley

Oh my! Mindboggling!
I am afraid you lost me when it come to a cross between a graft-chimarea and
a non-chimaera. What is the view we should take of the pollen of a
graft-chimaera? (this is the relevant factor, IIUIR?)
PvR

Stewart Robert Hinsley schreef
The following is speculation.

Many plants have 3 layers of tissue in the meristem.

Lavatera x clementii 'Rosea' is non-chimaeric, and has rose-coloured
petals with a rose-red eye. Let us denote the composition of the 3
layers in this cultivar as RRR.

Lavatera x clementii 'Barnsley', to the best of my knowledge, is a sport
of 'Rosea'. It has flowers that open white, with the same rose-red eye.
The flowers turn pink as the age. It is known to be a periclinal
chimaera, and also is observed to have a propensity to revert to a rose-
flowered state. Let conjecture, for reasons which should become clear,
that the composition of the 3 layers is WRR.

Lavatera x clementii 'Blushing Bride', to the best of my knowledge, is a
sport of 'Barnsley'. The flowers age to a slightly paler pink than
'Barnsley', and it does not have the same tendency to revert. (I've seen
one source that says that this variety to not change colour as it ages,
but consider the cultivar name, I'm confident that that source is in
error.) I conjecture that this is WWR.

There are cultivars with similar flowers which don't turn pink with age,
which would be WWW. 'Lisanne' is, I believe, a cross between Lavatera
thuringiaca 'Ice Cool' (which has pure white flowers, including the eye)
and 'Barnsley' - I have been told that it's a sport of 'Barnsley', but
the habit differs, and is similar to the supposed seed parent, so I find
that explanation more convincing. 'Memories' (aka 'Stelav') also has a
compact habit, and may be a similar cross.

It may be the case that the aging to pink is an effect of the R genotype
on W genotype tissue.

Lavatera x clementii 'Candy Floss' ('Cotton Candy' from some US
suppliers) has a colour pattern very similar to 'Rosea' (perhaps a
fraction paler), but has a herbaceous habit, and differently shaped
flowers. It seems to me that this is a similar cross, but with 'Rosea'
as the parent instead of 'Barnsley', and perhaps wild-type thuringiaca
rather than 'Ice Cool'.
--
Stewart Robert Hinsley

An interesting known periclinal chimera in citrus is the 'Thompson Pink'
grapefruit. It's peel is genetically 'Marsh' white grapefruit, and its
apomictic seeds always produce 'Marsh' trees. But the middle layer, which
produces the edible pulp, makes the pink pigment (lycopene) that 'Marsh' does
not. 'Burgundy' grapefruit, a very much darker-colored variety, is also likely
a periclinal chimera of the same type.