Gossypium hirsutum L., cotton
Taxonomic lineage
cellular organisms - Eukaryota - Viridiplantae - Streptophyta - Streptophytina - Embryophyta - Tracheophyta - Euphyllophyta - Spermatophyta - Magnoliophyta - eudicotyledons - core eudicotyledons - rosids - eurosids II - Malvales - Malvaceae - Malvoideae - Gossypium - Gossypium hirsutum
Brief facts
- The genus Gossypium consists of about 50 species, only four of which (G. hirsutum, G. barbadense, G. arboreum, and G. herbaceum) are domesticated and produce spinnable fiber. G. hirsutum and G. barbadense are New World tetraploids (2n = 4x = 52; AD genome species), and G. arboreum and G. herbaceum are Asian-African diploids (2n = 26; A) genome species. India is the only country where all four species are grown and where about 20-30% of cotton produced consists of G. arboreum.
- G. hirsutum is considered the most important of the cotton-yielding plants, providing about 87% of commercial cottons.
- The archeological evidence from five caves in the Tehuacán Valley area of Mexico shows that cotton (New World tetraploid) together with maize, peppers, beans, squash, avocados, and other plants were cultivated as early as 7,000 years ago. Cotton appears both in manufactured material and in the form of crude fiber and boll fragments.
- Wild cotton is a perennial shrub or occasionally a small tree up to 5 m tall. In nature it grows mainly in coastal and river overflow areas, along roads and other disturbed habitats.
- Vegetative parts of cotton contain gossypol, a sesquiterpinoid, which has been shown to have strong antifertility, antitumor, anti-parasite, and anti-HIV properties.
Developmental stages (life cycle)
Cotton is cultivated as an annual. It takes about 130-160 days from plant emergence to harvest.
- seed stage
- dormant seed Cotton seed can maintain viability for several years.
- germination Germination and emergence can take 4-14 days (up to 41 days); cotton germination is epigeal: at the soil surface the hypocotyl straightens and pulls the folded cotyledons out of the soil.
- vegetative
- seedling
- emergence After the cotyledons are pulled through the soil surface, they unfold and expose the epicotyl and the apical meristem; at this point, germination and seedling emergence are complete and the plant begins its active vegetative growth.
- first true leaf The first true leaf appears in a week or so after seedling establishment; most active root development begins.
- first square A first square, a fruiting bud, appears on the main stem in 35-45 days after emergence; the square develops into a fruiting branch that can also produce up to four squares.
- Nth square A new node with a square is produced from the apical meristem in average of every 3 days.
- seedling
- reproductive
- flowering
A cotton plant typically blooms or flowers for about 6 weeks;
it takes about 21 days from square to bloom; one flower stays open for about
5-7 days; pollination occurs on first day when the flower is white; next day the flower
becomes pink;
the stage of cotton development is measured in terms of Nodes Above White Flower (NAWF).
- early flowering When the cotton plant first begins to bloom there will be approximately 9 to 10 NAWF.
- late flowering As the flowering approaches the top of the plant, the plant eventually puts all of its energy into boll development; this event is called cutout; cutout generally occurs at 4-5 NAWF; at cutout, no more harvestable fruit is set.
- boll development
It takes approximately 50 days for a boll to open after
fertilization occurs.
- boll enlargement Boll enlargement lasts about 3 weeks; during this time the fibers produced on the seed are elongating and the maximum volume of the boll is attained.
- boll filling This phase begins during the fourth week after flowering; after this time, fiber elongation stops and secondary wall formation of the fiber begins; cellulose is deposited inside the fiber, filling the void space inside it.
- open boll After seed maturation is complete, the capsule walls of the boll dry; eventually the carpel walls split and the boll opens.
- flowering
A cotton plant typically blooms or flowers for about 6 weeks;
it takes about 21 days from square to bloom; one flower stays open for about
5-7 days; pollination occurs on first day when the flower is white; next day the flower
becomes pink;
the stage of cotton development is measured in terms of Nodes Above White Flower (NAWF).
References
-
Chaudhary B, Hovav R, Flagel L, Mittler R, Wendel JF.
Parallel expression evolution of oxidative stress-related genes in fiber from wild and domesticated diploid and polyploid cotton (Gossypium). BMC Genomics. 2009 Aug 17;10:378.
Evolutionary history of diploid and allotetraploid cotton (Gossypium). Phylogeny of the genus is shown, with the history of repeated domestication at both the diploid (n = 13) and polyploid (n = 26) levels. The ancestral A- and D-genome diploids are inferred to have diverged from a common ancestor ~5–10 million years ago, prior to genomic merger in a common polyploid nucleus ~1–2 million years ago [32]. The newly evolved allopolyploid lineage subsequently diversified into five species (three used for microarray analysis are shown). Two allotetraploid species, G. hirsutum (source of 'upland cotton') and G. barbadense (source of 'Pima cotton'), and the diploid species G. arboreum were domesticated by humans within the past ~7000 years [35,36]. In the present study, we used models of the two progenitor diploids, G. arboreum (A-genome) and G. raimondii (D-genome), and both wild and domesticated forms of G. hirsutum and G. barbadense. We also included G. tomentosum, a wild allopolyploid from Hawaii. A representative image of a single seed at maturation is also shown for each species, with attached trichomes ("cotton fiber") with average fiber length (G. raimondii = 1.6 cm; G. arboreum = 3.0 cm; wild G. hirsutum = 2.0 cm; domesticated G. hirsutum = 3.9 cm; wild G. barbadense = 2.4 cm; domesticated G. barbadense = 4.3 cm; G. tomentosum = 1.2 cm) (modified from Applequist et al. [31]. Arrows denote microarray comparisons between species, with graphs designating the number of differentially up-regulated genes (P < 0.05 and FDR < 0.01) in each species, using the same color codes as in the seed image outlines.
-
Zhang HB, Li Y, Wang B, Chee PW.
Recent advances in cotton genomics. Int J Plant Genomics. 2008.
Phylogeny and evolution of Gossypium species. The phylogenetic data is from Wendel and Cronn [2], the genome sizes are from Hendrix and Stewart [3], and genomic designations follow Endrizzi et al. [4] and Percival [5]. The species in bold face are cultivated. MYA: million years ago.
Cotton fiber development and corresponding morphogenesis stages. The initiation stage is characterized by the enlargement and protrusion of epidermal cells from the ovular surface; during the elongation stage the cells expend in polar directions with a rate of >2 mm/day; during the secondary cell wall deposition stage celluloses are synthesized rapidly until the fibers contain ∼90% of cellulose; and at the maturation stages minerals accumulate in the fibers and the fibers dehydrate.
-
Hovav R, Udall JA, Chaudhary B, Hovav E, Flagel L, Hu G, Wendel JF.
The evolution of spinnable cotton fiber entailed prolonged development and a novel metabolism. PLoS Genet. 2008 Feb;4(2):e25.
An Evolutionary and Development Model Describing Processes That Lead to the Formation of Spinnable Fiber.
An exceptional example of evolutionary innovation is the single-celled seed trichome in Gossypium ("cotton fiber"). Authors suggest that the evolution of long spinnable fibers in cotton was accompanied by novel expression of genes assisting in the regulation of reactive oxygen species levels.
-
Claudio L.
Waste couture: environmental impact of the clothing industry. Environ Health Perspect. 2007 Sep.
Each step of the clothing production process carries the potential for an environmental impact. For example, conventionally grown cotton, one of the most popular clothing fibers, is also one of the most water- and pesticide-dependent crops (a view disputed by Cotton Incorporated, a U.S. cotton growers' group). At the factory stage, effluent may contain a number of toxics (above, waste products from a garment factory in Dhaka, Bangladesh, spill into a stagnant pond).
Fierce global competition in the garment industry translates into poor working conditions for many laborers in developing nations. (top) A worker in Phnom Penh, Cambodia, rests on the floor of a garment factory. More than 2,000 young women work in this factory, producing clothes for shops in Europe and North America. (bottom) The owner of a textile factory in Dhaka threatens a child laborer, who works for 10 hours a day to earn US$1.
-
Frazer L.
New spin on an old fiber. Environ Health Perspect. 2004 Sep.
Spinning gold out of waste? Nearly a quarter of the 9.6 billion pounds of cotton fiber produced each year in the United States is lost to waste during harvesting, transport, and processing. A new technology uses electrospinning of waste cotton fibers, made possible by addition of a relatively benign solvent, to create high-value nanofibers (above).
- Smith CE, MacNeish RS Jr. Antiquity of American Polyploid Cotton. Science, New series, Vol.143, No. 3607 (Feb. 14, 1964), pp.675-676.
- Major topic "Gossypium" free full text articles in PubMed
- Major topic "Cotton Fiber" free full text articles in PubMed
Websites
Back to top
