Gossypium barbadense
Gossypium barbadense
Gossypium barbadense is a species of the genus cotton (Gossypium ). It is native to tropical America and is now widely grown for the production of cotton fibers.
Description
Gossypium barbadense grows as a perennial shrub or subshrub that reaches a height of 2 to 3 m. In cultivation the plant is grown as an annual. The shoot axis is dark reddish and edgy. The hair may extend to the whole plant, or be limited to the petioles and leaf veins on the underside of leaves. The leaves are three - or five-lobed, the leaves of the primary shoot axis also siebenlappig. The underside of the leaves is covered with nectaries. The lobes are oval to inversely egg-shaped and end long drawn out. The sheet reaches a diameter of 7 to 14 cm long, the base sheet has a heart -shaped, the blade shaft is longer than the leaf blade. The stipules are 1-5 cm long, they usually fall off soon.
The flowers appear singly in the leaf axils or terminally. The flower stalks are shorter than the petioles with 1-4 cm. The outer calyx consists of three, according to other data five or more non- intergrown bracts. They are 6 cm long and 4.5 cm wide, heart-shaped front with seven to neun19 pointed prongs at the base. Between the bracts are nectaries. The bowl-shaped cup is just cut off, ciliated, here are often located nectaries. The petals are bright yellow, each with a dark red spot at the base. They are 5-8 inches tall and are hairy on the outside. The Columna is 3.5 to 4 cm long, the stamens are close to her. The scar extends beyond the stamen tube significantly. The fruit capsule is three, rarely four-piece, oval to oblong, pointed toe or beaked. It is 3 to 7 cm long. The oval seeds are smooth and black, to 0.8 cm in size. They are surrounded by long white fibers and short, non-fixed fibers.
The chromosome number is 2n = 4x = 52
Dissemination
Gossypium barbadense is native to tropical America. It is cultivated in the tropics and subtropics worldwide. The four-time set of chromosomes of Gossypium barbadense derived from two different types of output ( Allopolyploidy ). However, a part of the chromosome set similar to that of American types, the second part of the African species. When the intersection of the two parental species took place is unclear: It was suggested a date prior to the separation of Africa and South America (in 60-100 million years ago ), or a replacement with the people a few hundred years ago. However, molecular genetic studies suggest an age of Gossypium barbadense 1-2 million years ago; such as the replacement of the now spatially separated on different continents output types took place is unclear.
Use
Gossypium barbadense is a supplier of cotton fibers. First finds of fibers are associated with the Gossypium barbadense, come from fishing nets on the coast of Peru, and dated to 1500-2400 BC. From there, the plant was used in pre-Columbian South America, the Caribbean and up to the Galápagos Islands. Even at this time, breeding changes can be observed: The short fibers around the seeds were less, the long fibers for longer and longer, also lost the seed coat of strength, so that the seeds germinate faster.