Earth:Basics of white flower colouration
White flower colour is related to the absence or reduction of the anthocyanidin content.[1] Unlike other colors, white colour is not induced by pigments. Several white plant tissues are principally equipped with the complete machinery for anthocyanin biosynthesis including the expression of regulatory genes. Nevertheless, they are unable to accumulate red or blue pigments, for example Dahlia ´Seattle´ petals showing a white tip.[2] Several studies have revealed a further reduction of the anthocyanidin to colorless epicatechin by the enzyme anthocyanidin reductase (ANR).[3]
Cultivation & Modification of Colour
Many external factors can influence colour: light, temperature, pH, sugars and metals.[4] There is a method to turn petunia flowers from white to transparent. The petunia flower is immersed into a flask of water, connected to a vacuum pump, after which the flower appeared colourless. The white colour is expressed by the air present in the vacuoles that absorb the light, without air the flower loses the white colour.
There is an increasing interest in flower colour,[citation needed] since some colorations are currently unavailable in plants. Ornamental companies create new flower colour by classical and mutation breeding and biotechnological approaches. For example, white bracts in Poinsettia are obtained by high frequency irradiation.
See also
References
- ↑ Kazuma, Kohei; Noda, Naonobu; Suzuki, Masahiko (November 2003). "Flavonoid composition related to petal color in different lines of Clitoria ternatea". Phytochemistry 64 (6): 1133–1139. doi:10.1016/s0031-9422(03)00504-1. ISSN 0031-9422. PMID 14568080. Bibcode: 2003PChem..64.1133K.
- ↑ Rosati*, Carlo; Cadic, Alain; Duron, Michel; Renou, Jean-Pierre; Simoneau, Philippe (1997-10-01). "Molecular cloning and expression analysis of dihydroflavonol 4-reductase gene in flower organs of Forsythia × intermedia" (in en). Plant Molecular Biology 35 (3): 303–311. doi:10.1023/A:1005881032409. ISSN 0167-4412. PMID 9349254.
- ↑ Fischer, Thilo C.; Mirbeth, Beate; Rentsch, Judith; Sutter, Corina; Ring, Ludwig; Flachowsky, Henryk; Habegger, Ruth; Hoffmann, Thomas et al. (2013-10-01). "Premature and ectopic anthocyanin formation by silencing of anthocyanidin reductase in strawberry (Fragaria × ananassa)" (in en). New Phytologist 201 (2): 440–451. doi:10.1111/nph.12528. ISSN 0028-646X. PMID 24117941.
- ↑ Biotechnology of ornamental plants. Geneve, R. L., Preece, John E., Merkle, Scott Arthur, 1953-. Wallingford, Oxon, UK: CAB International. 1997. ISBN 978-0851991108. OCLC 36340408.
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