The comparison of some drought resistance parameters in two Calligonum species (Calligonum persicum, C. stenopterum) in natural conditions

Drought is one of the most important factors in desert ecosystems that affect plant growth. In this study some of drought parameters were studied on Calligonum persicum, and C. stenopterum, under control and irrigated conditions in a field experiment. Water potential was estimated -34.2 and -27.8 in C. stenopterum and C. persicum respectively. Two species showed no significant differences on praline contents but soluble sugar was significantly higher in C. persicum compared to C. stenopterum. In contrast, relative water content and chlorophyll were significantly higher in C. stenopterum compared to Calligonum persicum. The amount of Na+ and K+ was not significant for the two species. Irrigation significantly decreased water potential in C. persicum and C. stenopterum. Irrigation also decreased proline content in two species, but its effects were significant on C. stenopterum. Irrigation decreased water potential and soluble sugar in C. stenopterum. Comparison of drought effects in control and irrigated conditions showed that osmotic adjustment is active in both species. We concluded that the two species may be able to adapt to their habitats because they are able to adjust their osmotic potential via proline accumulation.