Drought resistance of Calligonum bungei under natural conditions (Case study: Kalmande-Bahadoran Protected Area, Yazd province)

Aridity is one of the most important factors that affect plant growth and distribution in desert ecosystems. In this study, proline, soluble sugar, water potential, RWC, chlorophyll, Na+ and K+ were measured in Calligonum bungei under control and irrigated conditions in southern rangelands of Kalmand Protected Area, Yazd province. The experiment was done with six replicates in a completely randomized design. Results showed that plant water potential was higher before irrigation compared to irrigated conditions (-19.3 and -16.3 before and after irrigation respectively). Proline content was also significantly higher before than after irrigation (2.78 mg/gfw in control). The same pattern was observed for soluble sugar, where the highest amount of soluble sugar (67.8 mg/gfw) was measured in control. The amounts of K+ was significantly higher than Na+. There was nosignificant differences in the amount of Na+ and K+ and chlorophyl before and after irrigation. No significant differences in relative water content of the individuals was found; in average, the relative water content of all individuals was about 38 %. It is concluded that this species adapted to its own habitat to adjust osmotic potential mainly via proline as well as K+ and sugar accumulation.