View source for Variegation

{{short description|Leaf with uneven distribution of chlorophyll}}
{{about|variegation in botany|histology|Variegation (histology)}}
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[[image:Cryptocarya williwilliana - juvenile variegated.jpg|thumb|right|''[[Cryptocarya williwilliana]]'' showing leaf venation and variegated leaves.]]

'''Variegation''' is the appearance of differently coloured zones in the [[Leaf|foliage]], [[Flower|flowers]], and sometimes the [[Plant stem|stems]] and [[fruit]] of [[Plant|plants]], granting a speckled, striped, or patchy appearance. The colors of the patches themselves vary from a slightly lighter shade of the natural coloration to yellow, to white, or other colors entirely such as red and pink.<ref name= ":1" >{{Cite journal |last1=Zhang |first1=Jian-Hang |last2=Zeng |first2=Jin-Chu |last3=Wang |first3=Xiao-Mei |last4=Chen |first4=Shui-Fei |last5=Albach |first5=Dirk C. |last6=Li |first6=Hong-Qing |date=2020-11-01 |title=A revised classification of leaf variegation types |url=https://linkinghub.elsevier /retrieve/pii/S0367253020302024 |journal=Flora |volume=272 |pages=151703 |doi=10.1016/j.flora.2020.151703 |bibcode=2020FMDFE.27251703Z |issn=0367-2530}}</ref> This is caused by varying levels and types of [[Biological pigment|pigment]], such as [[chlorophyll]] in leaves.<ref name= ":0" >{{cite web |title=Variegated Leaves |url=http:// botgard.ucla.edu/html/botanytextbooks/generalbotany/shootfeatures/generalstructure/leafcolor/variegation.html |url-status=dead |archive-url=https://web.archive.org/web/20160615002817/http:// botgard.ucla.edu/html/botanytextbooks/generalbotany/shootfeatures/generalstructure/leafcolor/variegation.html |archive-date=2016-06-15 |access-date=9 July 2016 |website=UCLA College}}</ref> Variegation can be caused by [[Mutation|genetic mutations]] affecting pigment production, or by viral infections such as those resulting from [[Mosaic virus|mosaic viruses]].<ref>{{Cite journal |last1=Valverde |first1=Rodrigo A. |last2=Sabanadzovic |first2=Sead |last3=Hammond |first3=John |date=May 2012 |title=Viruses that Enhance the Aesthetics of Some Ornamental Plants: Beauty or Beast? |url=https://apsjournals.apsnet.org/doi/10.1094/PDIS-11-11-0928-FE |journal=Plant Disease |language=en |volume=96 |issue=5 |pages=600–611 |doi=10.1094/PDIS-11-11-0928-FE |pmid=30727518 |issn=0191-2917}}</ref> Many plants are also naturally variegated, such as [[Goeppertia insignis|''Goeppertia insignis'']]. Most of these are herbaceous or climbing plants, and are most often species native to tropical rainforests.<ref>{{Cite journal |last=Burtt |first=B. L. |date=1977 |title=Notes on the Rain-Forest Herbs |url=https://ia902803.us.archive.org/31/items/biostor-140081/biostor-140081.pdf |journal=Gardens' Bulletin, Singapore |volume=29 |pages=73–80}}</ref>

Many species which are normally non-variegated are known to display variegation. Their appearance is desirable to enthusiasts, and many such plants are [[Plant propagation|propagated]] and sold as unique [[Cultivar|cultivars]].<ref name= ":1" /> However, in individuals where the variegation occurs in normally-[[Photosynthesis|photosynthetic]] cells, the lack of functioning [[Chloroplast|chloroplasts]] can slow growth rate.<ref name= ":0" /> Conversely, naturally-variegated plants derive benefits from their appearance, such as improved photosynthetic efficiency in low-light conditions and herbivore deterrence.<ref>{{Cite journal |last1=Campitelli |first1=Brandon E. |last2=Stehlik |first2=Ivana |last3=Stinchcombe |first3=John R. |date=March 2008 |title=Leaf variegation is associated with reduced herbivore damage in Hydrophyllum virginianum |url=http:// nrcresearchpress /doi/10.1139/B07-139 |journal=Botany |language=en |volume=86 |issue=3 |pages=306–313 |doi=10.1139/B07-139 |issn=1916-2790}}</ref><ref>{{Cite journal |last=Givnish |first=T. J. |date=1990 |title=Leaf Mottling: Relation to Growth Form and Leaf Phenology and Possible Role as Camouflage |url=https:// jstor.org/stable/2389314 |journal=Functional Ecology |volume=4 |issue=4 |pages=463–474 |doi=10.2307/2389314 |jstor=2389314 |bibcode=1990FuEco...4..463G |issn=0269-8463}}</ref>

The term is also sometimes used to refer to colour zonation in [[Mineral|minerals]] and the [[Integumentary system|integument]] of [[Animal|animals]].

== Causes ==
=== Chimeral ===
[[Image:Ficus carica Panascè.jpg|right|thumb|300px|Variegation of fruits and wood in ''[[Ficus carica]]'' 'Panascè', a bicolor (yellow-green) common fig cultivar. This Italian cultivar is a ''[[Chimera (plant)|chimera]]''.]]
[[Chimera (genetics)|Chimeric]] plants contain tissues with more than one [[genotype]].{{Explain|reason=How and why do chimeras occur in plants? What does it mean to have two different genotypes present in neighboring cells?|date=November 2024}} A variegated chimera contains some tissues that produce chlorophyll and other tissues which do not.<ref>{{cite web |last1=Lineberger |first1=Daniel |title=Origin, Development, and Propagation of Chimeras |url=https://aggie-hort.tamu.edu/tisscult/Chimeras/chimeralec/chimeras.html |website=aggie-horticulture.tamu.edu |access-date=29 January 2023}}</ref> Because the variegation is due to the presence of two kinds of plant tissue, propagating the plant must be by a vegetative method of propagation that preserves both types of tissue in relation to each other. Typically, stem [[Cutting (plant)|cuttings]], bud and stem [[grafting]], and other propagation methods that results in growth from leaf axil buds will preserve variegation.{{Citation needed|date=November 2024}} Cuttings with complete variegation may be difficult, if not impossible, to propagate.{{Why|date=November 2024}} Root cuttings will not usually preserve variegation, since the new stem tissue is derived from a particular{{Which|date=November 2024}} tissue type within the root.{{Citation needed|date=November 2024}}

=== Structural ===

Some variegation is caused by [[Structural coloration|structural color]], not pigment; the microscopic structure of the plant itself reflects light to produce varying colors. This can happen when an air layer is located just under the [[Epidermis (botany)|epidermis]] resulting in a white or silvery reflection.<ref>{{Cite journal |last1=Konoplyova |first1=Aelita |last2=Petropoulou |first2=Yiola |last3=Yiotis |first3=Charilaos |last4=Psaras |first4=George K. |last5=Manetas |first5=Yiannis |date=2008-11-01 |title=The fine structure and photosynthetic cost of structural leaf variegation |url=https:// sciencedirect /science/article/abs/pii/S0367253008000807 |journal=Flora - Morphology, Distribution, Functional Ecology of Plants |volume=203 |issue=8 |pages=653–662 |doi=10.1016/j.flora.2007.10.007 |bibcode=2008FMDFE.203..653K |issn=0367-2530}}</ref> It is sometimes called blister variegation.{{Citation needed|date=November 2024}} [[Pilea cadierei|''Pilea'' ''cadierei'']] (aluminum plant) shows this effect. Leaves of most ''[[Cyclamen]]'' species show such patterned variegation, varying between plants, but consistent within each plant.

The presence of hairs on leaves, which may be coloured differently from the leaf itself, can also produce variable coloration. This is found in various ''[[Begonia]]'' species and their hybrids.

Sometimes venal variegation occurs – the veins of the leaf are picked out in white or yellow. This is due to lack of green tissue above the veins. It can be seen in some [[Araceae|aroids]]. The [[Silybum marianum|blessed milk thistle]], ''Silybum marianum'', is a plant in which another type of venal variegation occurs, but in this case it is due to a blister variegation occurring along the veins.

=== Pigmentary ===
[[Image:TrifoliumPratense2.jpg|thumb|Leaves of [[red clover]] (''Trifolium pratense'') have a typical v-shaped variegation.|alt=]]

A common cause of variegation is the masking of green [[pigment]] by other pigments, such as [[anthocyanin]]s. This often extends to the whole leaf, causing it to be reddish or purplish. On some plants however, consistent zonal markings occur; such as on some clovers, [[Bromeliaceae|bromeliads]], certain ''[[Pelargonium]]'' and ''[[Oxalis]]'' species. On others, such as the commonly grown forms of [[Coleus scutellarioides|Coleus]], the variegation can vary widely within a population. In ''[[Nymphaea lotus]]'', the tiger lotus, leaf variegations appear under intense illumination.

=== Pathological ===
[[Virus]] infections may cause patterning to appear on the leaf surface. The patterning is often characteristic of the infection. Examples are the ''mosaic viruses'', which produce a mosaic-type effect on the leaf surface or the [[citrus variegation virus]] (CVV). Recently{{when?|date=January 2017}} a virus disease, ''[[Hosta virus X]]'' (HVX) has been identified that causes mottled leaf coloring in [[hostas]]. At first, diseased plants were propagated and grown for their mottled foliage, at the risk of infecting other healthy hostas.<ref>{{cite web|title=Hosta Virus X|url=http:// missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/viruses/hosta-virus-x.aspx|website=Missouri Botanical Garden|access-date=9 July 2016}}</ref> While these diseases are usually serious enough that the gardener would not grow affected plants, there are a few affected plants that can survive indefinitely, and are attractive enough to be grown for ornament; e.g. some variegated [[Abutilon]] varieties. [[Nutrient]] deficiency symptoms may cause a temporary or variable yellowing in specific zones on the leaf. [[Iron]] and [[magnesium]] deficiencies are common causes of this. [[Transposable element]]s can cause colour variegation.<ref>{{cite web|title=Barbara McClintock and the Discovery of Jumping Genes (Transposons)|url=http:// nature /scitable/topicpage/barbara-mcclintock-and-the-discovery-of-jumping-34083#|website=Nature|access-date=9 July 2016}}</ref>

=== Defensive masquerade ===
It has been suggested that some patterns of leaf variegation may be part of a "defensive masquerade strategy." <ref>{{cite journal |last=Lev-Yadun |first=S. |date=2014 |title=Defensive masquerade by plants |journal=Biological Journal of the Linnean Society |volume=113 |issue= 4|pages=1162–1166 |doi=10.1111/bij.12399 |doi-access=free }}</ref> In this, leaf variegation may appear to a [[leaf miner|leaf mining insect]] that the leaf is already infested, and this may reduce parasitization of the leaf by leaf miners.<ref>{{cite web |url=http://news.bbc.co.uk/earth/hi/earth_news/newsid_8108000/8108940.stm |title=The plant that pretends to be ill |last1=Walker |first1=Matt |date=19 June 2009 |website=BBC News |access-date=13 April 2016 }}</ref>

== Nomenclature ==
By convention, the italicised term ''<nowiki/>'variegata''' as the second part of the Latin [[Binomial nomenclature|binomial]] name, indicates a [[species]] found in the wild with variegation (''[[Aloe variegata]]''). The much more common, non-italicised, inclusion of 'Variegata' as the third element of a name indicates a variegated [[cultivar]] of an unvariegated parent (''[[Aucuba japonica]]'' 'Variegata'). However, not all variegated plants have this Latin tag, for instance many cultivars of ''[[Pelargonium]]'' have some zonal variegation in their leaves. Other types of variegation may be indicated, e.g. ''[[Daphne odora]]'' 'Aureomarginata' has yellow edging on its leaves.

== Usage ==
[[Image:Variegated foliage.JPG|thumb|Variegated foliage used in an English garden. Plants shown include ''[[Aralia elata]]'' 'Aureovariegata' and ''[[Carex ornithopoda]]'' 'Variegata'|alt=]]

Variegated plants have long been valued by gardeners, as the usually lighter-coloured variegation can 'lift' what would otherwise be blocks of solid green foliage. Many gardening societies have specialist variegated plants groups, such as the [[Hardy Plant Society]]'s Variegated Plant Special Interest Group in the UK.

In 2020, a variegated ''[[Rhaphidophora tetrasperma]]'' plant sold at auction for US$5,300.<ref>{{cite web |last1=Debczak |first1=Michele |title=The World's Most Expensive Houseplant Just Sold for $20,000 in New Zealand |url=https:// mentalfloss /article/648116/most-expensive-houseplant-sells-20000-new-zealand |website=Mental Floss |date=7 July 2021 |access-date=28 January 2023}}</ref> In June 2021, another variegated ''Rhaphidophora tetrasperma'' plant sold at auction for US$19,297.<ref>{{cite web |last1=Cullinane |first1=Susannah |title=New Zealand houseplant sells for $19,200 in online bidding war |url=https:// cnn /2021/06/13/asia/new-zealand-houseplant-trademe-auction-trnd/index.html |website=CNN |date=13 June 2021 |access-date=28 January 2023}}</ref>
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== See also ==
* [[Glossary of botanical terms]]

== References ==
{{reflist}}

== External links ==
{{Commons category|Chlorophyll-lacking plants}}

[[Category:Plant physiology]]
[[Category:Chimerism]]