Zinc and phosphorus interaction in nutrient solution affecting lettuce growth and yield

The experiment was carried out to evaluate the effect of Zn and P levels in nutrient solution on Zn and P absorption and lettuce yield (Lactuca saliva L.). A randomized block experimental design in 3 x 3 factorial arrangement with three replications was used. The treatments were three Zn levels: low , normal and high, corresponding to 0.0, 1.5 and 6.0 muM L-1 and three P le vels: low, normal and high, corresponding to 0.01, 1.5 and 6.0 mM L-1 as Zn SO4. 7H(2)O and KH2PO4. Twenty six days after transplantation (DAT), the le af area and leaf dry weight were not influenced by the treatments. At 52 DA T, the leaf area, the leaf number and the shoot dry weight were not affecte d by Zn addition when the P level was low; but when P levels were normal an d high, the normal and high Zn levels lead to the highest leaf area, leaf n umber, and shoot dry weight. Phosphorus concentrations in the marketable le aves at each Zn level were similar at P normal and high addition levels. Th e highest P concentration was observed in the stem followed by roots and ma rketable leaves. Zinc concentrations in the marketable leaves, stem and roo ts, increased with Zn addition to the nutrient solution.