Diurnal water relations of inland and coastal halophytic populations from Pakistan

The diurnal water relations of three halophytic species common to both inland and coastal habitats in saline flats of Karachi, Pakistan were studied. The first hypothesis was that species with different adaptation modes [leaf succulent (Suaeda fruticosa(L.) Forssk.), recreting (Atriplex griffithiiMoq. var.stocksiiBoiss.) and non-recreting (Heliotropium currassavicumL.)] have different patterns of water relations. The second hypothesis was that the coastal populations were more stressed in comparison to inland populations. The first hypothesis was rejected because the overall diurnal variation pattern of water relations was similar in all three species. There were quantitative differences in all parameters studied in various species from inland and coastal populations, and species also showed some individual differences in their responses to stress. The second hypothesis was accepted because coastal populations were generally more stressed in comparison to inland populations.