NaCl Effects on Water Relations and Accumulation of Mineral Nutrients in Shoots, Roots and Cell Sap of Wheat Seedlings

Two cvs. of Triticum durum Desf. differently sensitive to drought and to heavy metal excess (cv. Ofanto more tolerant than cv. Adamello) were exposed to 0, 50 and 100 mmol/L NaCl nutrient solutions for 9 days in a controlled environment. To investigate the effect of NaCl and to monitor possible differences in the responses of the two cvs., we determined growth parameters, leaf water relations and mineral nutrient accumulation in cell saps of the seedlings. The highest salt concentration reduced shoot growth, particularly in cv. Adamello, and shoot and root biomass production. In both cvs., water potential (ΨW) and osmotic potential (Ψπ) decreased with salinity and the osmotic adjustment that occurred, due to an accumulation of Na, Cl and also K in the cell sap, maintained turgor. NaCl determined an alteration of nutrient uptake, due to an accumulation of Na+ and Cl- both in shoots and roots. In particular, cv. Adamello showed higher decreases in the Ca++ of roots and the K+ of shoots and a higher increase in the Na+ of shoots. Even though both cvs. seem to be able to react to the stress, the results suggest a greater sensitivity of cv. Adamello to NaCl.