"Double-flowered" describes varieties of flowers with extra petals, often containing flowers within flowers. A flower, also known as a bloom or Blossom, is the reproductive structure found in Flowering plants (plants of the division Magnoliophyta, also A petal (from Ancient Greek petalon "leaf" "thin plate" regarded as a highly modified leaf is one member or part of the corolla [1][2] The double-flowered trait is often noted alongside the scientific name with the abbreviation fl. pl. (flore pleno, meaning "full flowered"). [3] The first abnormality to be documented in flowers, double flowers are popular varieties of many commercial flower types, including roses, camellias and carnations. A rose is a perennial flowering Shrub or vine of the Genus Rosa, within the family Rosaceae, that contains over 100 species Camellia ( ( Japanese: 椿 Tsubaki) is a Genus of Flowering plants in the family Theaceae, native to eastern and southern Dianthus caryophyllus ( Clove Pink) is a species of Dianthus. Where seed is available few double varieties "come true" from seed; many double flower varieties have no reproductive organs — as a result, they are sexually sterile and must be propagated through cuttings.
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History
Double flowers are the earliest documented form of floral abnormality, first recognized more than two thousand years ago. [2] Theophrastus mentioned double roses in his Enquiry into Plants, written before 286BC. Theophrastus ( Greek:; 371 – c 287 BC a Greek native of Eressos in Lesbos, was the successor of Aristotle in the Peripatetic Pliny also described double roses in 1st century BC. Gaius or Caius Plinius Secundus, ( AD 23 – August 25, AD 79 better known as Pliny the Elder, was an ancient Author In China, double peonies were known and selected by around 750AD, and around 1000AD double varieties of roses were cultivated to form the China rose (one of the ancestors of modern Hybrid Tea roses). For the ancient Balkan region and tribe see Paionia. The peony or paeony ( Paeonia) is the only genus in the Rosa chinensis, known commonly as the China Rose is a member of the genus Rosa native to central China in Guizhou, Hybrid Tea is a Cultivar Group of Roses created by cross-breeding two different types of roses [4] Today, most cultivated rose varieties bear this double-flower trait.
Herbalists of the Renaissance recognized double flowers and began to cultivate them in their gardens — Rembert Dodoens published a description of double flowers in 1568, and John Gerard created illustrations of many double flowers beside their wild-type counterparts in 1597. Rembert Dodoens ( Mechelen June 29, 1517 &ndash Leyden March 10, 1585) was a Flemish Physician and See also John Gerard SJ John Gerard ( Nantwich, 1545 &ndash February 1611/12 in London) was an English A double-flowered variety of Marsh Marigold was discovered and cultivated in Austria in the late 16th century, becoming a valued garden plant. Caltha palustris commonly known as Kingcup or Marsh Marigold (also known as Calthus palustris syn [5]
The first documented double-flowered mutant of Arabidopsis, a model organism for plant development and genetics, was recorded in 1873. Arabidopsis thaliana ( A-ra-bi-dóp-sis tha-li-á-na; thale cress, mouse-ear cress or Arabidopsis) is a small [6] The mutated gene likely responsible for the phenotype, AGAMOUS, was cloned and characterized in 1990 in Elliot Meyerowitz's lab as part of his study of molecular mechanisms of pattern formation in flowers. Elliot Meyerowitz (born May 22, 1951) is a US biologist He is currently George W [7]
Genetics of double-flower mutations
Double-flower forms often arise when some or all of the stamens in a flower are replaced by petals. The stamen ( Plural stamina or stamens, from Latin stamen meaning "thread of the warp " is the male A petal (from Ancient Greek petalon "leaf" "thin plate" regarded as a highly modified leaf is one member or part of the corolla These types of mutations, where one organ in a developing organism is replaced with another, are known as homeotic mutations. Homeosis is the transformation of one body part into another arising from Mutation in or misexpression of specific developmentally critical Genes It may be caused They are usually recessive, although the double flower mutation in carnations exhibits incomplete dominance. [8]
In Arabidopsis, which has been used as a model for understanding flower development, the double-flower gene AGAMOUS encodes a protein responsible for tissue specification of stamen and carpel flower segments. Arabidopsis thaliana ( A-ra-bi-dóp-sis tha-li-á-na; thale cress, mouse-ear cress or Arabidopsis) is a small A gynoecium (from Ancient Greek gyne, "woman" is the Female reproductive part of a Flower. When both copies of the gene are deleted or otherwise damaged, developing flowers lack the signals to form stamen and carpel segments. Regions which would have formed stamens instead default to petals and the carpel region develops into a new flower, resulting in a recursive sepal-petal-petal pattern. A sepal (from Latin separatus "separate" + petalum "petal" is a part of the flower of Angiosperms or flower plants Because no stamens and carpels form, the plants have no reproductive organs and are sexually sterile.
Mutations affecting flower morphology in Arabidopsis can be described by the ABC model of flower development. In this model, genes involved in flower formation belong to one of three classes of genes: A class genes which affect sepal and petal formation, B class genes which affect petal and stamen formation, and C class genes which affect stamen and carpel formation. These genes are expressed in certain regions of the developing flower and are responsible for development of organs in those regions. Agamous is a C class gene, a transcription factor responsible for activating genes involved in stamen and carpel development. In the field of Molecular biology, a transcription factor (sometimes called a sequence-specific DNA binding factor is a Protein that binds to specific sequences
Gallery
 Most garden roses are double-flowered |
 Double-flowered lilac, often called "French lilac" |
 Double-flowered Camellia |
 Double-flowered carnations |
 Double-flowered petunia |
 Double-flowered peony |
References
- ^ Genes for unusual 'flower within a flower' are identified by UCSD scientists. A rose is a perennial flowering Shrub or vine of the Genus Rosa, within the family Rosaceae, that contains over 100 species The unrelated but somewhat similar-looking Chinaberry ( Melia azedarach) is sometimes called "lilac" too Camellia ( ( Japanese: 椿 Tsubaki) is a Genus of Flowering plants in the family Theaceae, native to eastern and southern Dianthus caryophyllus ( Clove Pink) is a species of Dianthus. For Petunia Pig, a Looney Tunes character see Petunia Pig For Aunt Petunia see Aunt Petunia For For the ancient Balkan region and tribe see Paionia. The peony or paeony ( Paeonia) is the only genus in the Retrieved on 2008-03-06. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1079 - Omar Khayyám completes the Iranian calendar. 1454 - Thirteen Years' War: Delegates of
- ^ a b Meyerowitz EM, Smyth DR, and Bowman JL (1989). "Abnormal flowers and pattern formation in floral development". Development 106: 209-217.
- ^ William Thomas Stearn (2004). Botanical Latin. Timber Press, 355. ISBN 0881926272.
- ^ Wang GuoLiang (2007). "A study on the history of Chinese roses from ancient works and images". Acta Horticulturae 751: 347-356.
- ^ D. Onno Wijnands (1993). "The double-flowered Caltha palustris". Euphytica 73 (3).
- ^ E. M. Meyerowitz (2001). "Prehistory and History of Arabidopsis Research". Plant Physiology 125: 15-19.
- ^ M. F. Yanofsky, H. Ma, J. L. Bowman, G. N. Drews, K. A. Feldmann & E. M. Meyerowitz (1990). "The protein encoded by the Arabidopsis homeotic gene agamous resembles transcription factors". Nature 346: 35-39.
- ^ Sagawa Y and Mehlquist GAL. "Some X-ray Induced Mutants In Carnation". Journal of Heredity 50 (2): 78-80.
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