Growth and mineral absorption in maize seedlings as affected by increasing NaCl concentrations

The influence of NaCl solutions of decreasing osmotic potentials (¥π = ‐0.44 and ‐0.88 MPa) on seedling growth and on the concentration of the most important macro‐ and micro‐nutrients in the shoots and roots of maize (Zea mays L., cv. Summer II) grown in Hoagland's solution in a growth chamber was studied. Salt stress was imposed on six‐day‐old seedlings for a three day period. Increasing NaCl concentrations induced a reduction in the leaf water potential and a significant decrease in the length and dry weight of the shoots, whereas these two parameters decreased in the roots only at the lowest osmotic potential.

Although the absorption and accumulation of nutrients upon salt stress differed in the two treatments depending on the plant tissue and nutrient, almost all of the macronutrients decreased in the roots and shoots, showing the lowest values at ¥π = ‐0.88 MPa. Sodium and Cl increased continuously, much more in the roots than in the shoots.

A different response was seen in the shoots and roots in terms of micronutrients. In the roots, almost all of the ions reached their maximum concentrations at ¥π = ‐0.88 MPa; whereas in the shoots, they decreased at ¥π = ‐0.44 MPa without undergoing any further decrease at the lowest osmotic potential.