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a patch of skin that is discolored but not usually elevated; caused by various diseases (同)macula
variability in coloration
northern North America; Greenland; northern and central Europe (同)variegated scouring rush, Equisetum variegatum
change the appearance of, especially by marking with different colors

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(特に,花・葉が)不規則な色の斑点がある,まだら模様の
(特に植物の)多彩な色合い,雑色,まだら

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/04/27 11:24:11」(JST)

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This article is about variegation in botany. For histology, see Variegation (histology).

Variegation of fruits and wood in Ficus carica Panascè, a bicolor (yellow-green) common fig cultivar. This italian cultivar is a chimera

Variegation is the appearance of differently coloured zones in the leaves, and sometimes the stems, of plants. This may be due to a number of causes. Some variegation is attractive and ornamental and gardeners tend to preserve these. The term is also sometimes used to refer to colour zonation in flowers, minerals, and the skin, fur, feathers or scales of animals.

Chimeral

Plants bearing such variegation are chimeras, with more than one type of genetic makeup in their tissues. A lack of chlorophyll producing tissue in some tissues causes variegation with white or yellow coloured zones on the leaf, contrasting with the usual green tissue. It is due to some of the plant’s meristematic tissue losing the ability to produce chloroplasts, so that the tissue it produces is no longer green.

In a common type of such variegation, the part of the meristem that produces epidermal tissue loses the ability to produce chloroplasts. The margins of leaves may be composed only of cells derived from this merismatic tissue. Hence, this marginal tissue is white or yellow, rather than green. There are several other types of such variegation, depending on the tissues that have been affected, and their relationship to each other. Variegation may be consistent and symmetric in appearance throughout the whole plant, or it may be quite random in location. In some plants, entire branches or stems including the leaves may be variegated. The variegation in some forms is unstable. The extent and nature of the variegation can vary, and sometimes the plant will return to the green form. In others it is stable and does not change under normal conditions.

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 cuttings, bud and stem grafting, and other propagation methods that results in growth from leaf axil buds will preserve variegation. Cuttings with complete variegation may be difficult if not impossible to propagate. Root cuttings will not usually preserve variegation, since the new stem tissue is derived from a particular tissue type within the root.

As these plants have some of their tissue unable to carry out photosynthesis, the plant will be weaker than the plain green plant. They should generally be expected to die out in nature and their only real source of survival is through cultivation.

Reflective

Variegation in holly leaves

Reflective variegation in Pilea cadierei.

Some variegation is due to visual effects due to reflection of light from the leaf surface. This can happen when an air layer is located just under the epidermis resulting in a white or silvery reflection. It is sometimes called blister variegation.

Pilea (aluminum plant) is an example of a house plant that shows this effect. Leaves of most Cyclamen species show such patterned variegation, varying between plants, but consistent within each plant.

Another type of reflective variegation is caused by hairs on parts of the leaf, which may be coloured differently from the leaf. This is found in various Begonia species and garden 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 aroids.

The 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

Leaves of Red Clover (Trifolium pratense) have a typical v-shaped variegation.

A common cause of variegation is the masking of green pigment by other pigments, such as anthocyanins. 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, bromeliads, certain Pelargonium and Oxalis species. On others, such as the commonly grown forms of 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). Hosta Virus X (HVX)^[1] has caused such dramatic and attractive mosaic-type variegations that, when the disease was new to the United States, affected plants were mistakenly thought to be new mutations and were registered as new cultivars.^[2]

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.

Nomenclature

By convention, the italicised term variegata as the second part of the Latin 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.

Garden plants

Variegated foliage used in an English garden. Plants shown include Aralia elata 'Aureovariegata' and Carex ornithopoda 'Variegata'

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. Several gardening books which deal exclusively with variegated plants are available.

The rare rainforest plant, Cryptocarya williwilliana showing leaf venation and variegated leaves

Notes

^ Hosta Library: HVX
^ HVX-Infected Cultivars in the Marketplace

References

Variegated Plants - article from Union County College, New Jersey.
BBC: Earth News - article suggesting that some variegation is to feign disease.

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English Journal

Anatomical and physiological differences and differentially expressed genes between the green and yellow leaf tissue in a variegated chrysanthemum variety.

Chang Q, Chen S, Chen Y, Deng Y, Chen F, Zhang F, Wang S.SourceCollege of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
Molecular biotechnology.Mol Biotechnol.2013 Jun;54(2):393-411. doi: 10.1007/s12033-012-9578-8.
The leaves of the chrysanthemum variety 'NAU04-1-31-1' are variegated with distinct green and yellow sectors. The chlorophyll content of the yellow leaf tissue is less than that in the green one. The chloroplasts in the yellow leaf tissue were vacuolated, lacked thylakoid membrane structure and cont
PMID 22782702

Gray matter density in relation to different facets of verbal creativity.

Fink A, Koschutnig K, Hutterer L, Steiner E, Benedek M, Weber B, Reishofer G, Papousek I, Weiss EM.SourceInstitute of Psychology, University of Graz, Universitaetsplatz 2/III, 8010, Graz, Austria, andreas.fink@uni-graz.at.
Brain structure & function.Brain Struct Funct.2013 May 1. [Epub ahead of print]
Neuroscience studies on creativity have revealed highly variegated findings that often seem to be inconsistent. As recently argued in Fink and Benedek (Neurosci Biobehav Rev, 2012), this might be primarily due to the broad diversity in defining and measuring creativity as well as to the diversity of
PMID 23636224

Silence, activate, poise and switch! Mechanisms of antigenic variation in Plasmodium falciparum.

Guizetti J, Scherf A.SourceUnité de Biologie des Interactions Hôte-Parasite, Département de Parasitologie et Mycologie, Institut Pasteur, 25 Rue du Dr. Roux, Cedex 15, F-75724, Paris, France; CNRS URA2581, Institut Pasteur, 25 Rue du Dr. Roux, Cedex 15, F-75724, Paris, France.
Cellular microbiology.Cell Microbiol.2013 May;15(5):718-26. doi: 10.1111/cmi.12115. Epub 2013 Feb 21.
Phenotypic variation in genetically identical malaria parasites is an emerging topic. Although antigenic variation is only part of a more global parasite strategy to create adaptation through epigenetically controlled transcriptional variability, it is the central mechanism enabling immune evasion a
PMID 23351305

Japanese Journal

Positive correlation between tolerance to continuous UV-B irradiation, chloroplast numbers, chlorophyll content, and starch grain content in normal and variegated Japanese butterbur (Petasites japonicus) leaves

YAMASAKI Seiji,AKIYOSHI Yuko,YAMANAKA Saori [他]
福岡教育大学紀要. 第3分冊, 数学・理科・技術科編 = Bulletin of Fukuoka University of Education. 福岡教育大学編 (64), 59-68, 2015
NAID 40020373433

Variegated Adaptations : State Formation in Bengal from the 5th to the 7th Century (Conferences & Lectures : The Second International Symposium of Inter-Asia Research Networks : State Formation and Social Integration in Pre-modern South and Southeast Asia : A Comparative Study of Asian Society) -- (Formation of State and Society during the Period of the 5th-14th Centuries)