|
|
|
|
|
Saharan Cypress
The Saharan Cypress Cupressus dupreziana is a very rare coniferous tree native to the Tassili n'Ajjer mountains in the central Sahara Desert, southeast Algeria, where it forms a unique population of trees hundreds of kilometres from any other trees. There are only 231 specimens of this critically endangered species, the largest about 20 m tall. The majority are very old, estimated to be over 2000 years old, with very little regeneration due to the increasing desertification of the Sahara. Rainfall totals in the area are estimated to be about 30 mm annually. This species is distinct from the allied Mediterranean Cypress C. sempervirens in its much bluer foliage with a white resin spot on each leaf, the smaller shoots often being flattened in a single plane. It also has smaller cones, only 1.5-2.5 cm long. The Moroccan Cypress C. atlantica is more similar, and is treated as a variety of the Saharan Cypress (C. dupreziana var. atlantica) by some authors. Probably as a result of its isolation and low population, the Saharan Cypress has evolved a unique reproductive system of male apomixis whereby the seeds develop entirely from the genetic content of the pollen. There is no genetic input from the female "parent", which only provides nutritional sustenance (Pichot et al., 2000). The Moroccan Cypress does not share this characteristic. The Saharan Cypress is occasionally cultivated in southern and western Europe, in part for ex situ genetic conservation, but also as an ornamental tree. References - Stewart, P.J. 1969. Cupressus dupreziana, threatened conifer of the Sahara. Biological Conservation 2: 10-12.
- Pichot, C., Fady, B., & Hochu, I. 2000. Lack of mother tree alleles in zymograms of Cupressus dupreziana A. Camus embryos. Ann. For. Sci. 57: 1722. Full article (pdf file)
- Pichot, C., El Mataoui, M., Raddi, S. & Raddi, P. 2001. Surrogate mother for endangered Cupressus. Nature 412: 39.
External link
|
 |
|
| Copyright 2005-2009 OnPedia.com. All Rights Reserved |
|
|