Effect of NaCl Salinity on Growth and Mineral Composition of Ziziphus spina-christi (L.) Willd.

Ziziphus spina-christi (L.) Willd. is a fruit tree species growing wild in arid and semi-arid areas of Asia and Africa where rural populations intensively use its fruits, leaves, bark and wood. However, little is known about the effects of salinity, a widespread problem in these regions, on early growth and mineral composition of this species. This study was conducted under controlled conditions to contribute to filling this gap. Six weeks old seedlings of Z. spina-christi germinated in a full strength Hoagland solution were subjected to 0, 40, 80 and 160 mM NaCl. Compared to the unstressed control salinity levels of 80 and 160 mM reduced plant height, leaf number, leaf chlorophyll, total leaf area and dry matter by >50%. Salinity levels of 40, 80 and 160 mM enhanced leaf water contents by 14, 16 and 17%, respectively and 160 mM NaCl raised the concentration of Na and Cl ions in leaf tissues 81- and 21-fold. The K/Na ratio, in contrast, was hardly affected by increasing salinity indicating adaptation or tolerance of Z spina-christi to low or moderate NaCl salinity. These results suggest that Z spina-christi could be an interesting species for re-vegetation of moderately degraded saline lands.