Data/hora: 01/06/2024 00:47:54

Biblioteca(s): | Embrapa Meio-Norte.
Data corrente: | 25/02/2000
Data da última atualização: | 25/02/2000
Autoria: | ADU, A. A.; YEO, A. R.; OKUSANYA, O. T.
Título: | The response to salinity of a population of Dactyloctenium aegyptium from a saline habitat in southern Nigeria.
Ano de publicação: | 1994
Fonte/Imprenta: | Journal of Tropical Ecology, v. 10, n. 2, p. 219-228, 1994.
Idioma: | Português
Conteúdo: | ABSTRACT. The effects of salinity upon the growth, photosynthesis, ion and water contents of a population of Dactyloctenium aegyptium originating froma saline site in Nigeria were investigated. Growth was unaffected by a salinity of 10% artificial sea water, but was reduced by one third in 20% and by two thirds in 30% artificial sea water respectively. Initial adjustment to salinity was due both to increases in the concentrations of sodium and potassium per unit dry weight and to reduced hydration, the latter being the more important at higher salinities. The potassium content of the plants did not fall below 200-250 mM, and the sodium to potassium ratio did not exceed three, even at the highest salinities. Variation in the concentration of nutrients (potassium, nitrate and sulphate) in the medium in the presence of 25% artificial sea water had significant effects upon growth, but these were small in relation to the inhibitory effect of the salinity. The reduction in growth could not be attributed to lack of osmotic adjustment or to nutrient deficiency, and was probably due to ion toxicity within the leaves. The tolerance to reduced hydration, combined with the ability to germinate in saline conditions previously observed, could enable D. aegyptium to establish in a saline soil. The population did not exhibit any halophytic characteristics but did survive with a low growth rate at salinities up to 50% artificial sea water. It is concluded that the species was able to colonize the saline site because of its inherent adaptability, rather than the possession of an ecotype adapted to saline conditions.
Palavras-Chave: | Adaptacao de gramineas.
Thesagro: | Solo Salino.
Thesaurus Nal: | Dactyloctenium aegyptium; Nigeria; salinity.
Categoria do assunto: | --
Registro original: | Embrapa Meio-Norte (CPAMN)
Exemplares: | CPAMN - (8347-1) - ADD - SP - -- - S 6556 -  - S 6556 - DIS