Nutritional Efficiency of Phosphorus in Lettuce

This work aimed to evaluate the efficiency of phosphorus absorption, translocation, and utilization in lettuce. A greenhouse experiment was arranged in a completely randomized design in a 5x2 factorial scheme to test five phosphorus doses (0, 100, 200, 300, and 500 mg dm-3) and two lettuce varieties (Lisa and Americana). The soil was incubated with limestone for pH correction. Following this procedure, a phosphate fertilization was carried and the lettuce seedlings were transplanted. Fertilization with nitrogen and potassium were applied as cover. Forty days after seedling transplantation, the plants were separated into root and aerial part to determine the following characteristics- aerial part dry matter (APDM); root dry matter (RDM); phosphorus content in the aerial part (PCAP); phosphorus content in the root (PCR); phosphorus accumulation in the aerial part (PAAP); phosphorus accumulation in the roots (PAR); phosphorus absorption efficiency (PAE); phosphorus translocation efficiency (PTE); phosphorus use efficiency in the aerial part (PUEAP) and root-aerial part ratio (R/AP). The results obtained allowed to conclude that RDM and R/AP had a significant interaction between the varieties and the P doses, with Lisa presenting the highest values of these characteristics at the lowest doses evaluated. The characteristics PCAP, PAAP and PAE presented a significant difference between the varieties, with the Americana presenting the highest values. The characteristics PCAP, PAAP, EAP, APDM and PUEAP presented a significant difference between the P doses, with the highest values found at the dose of 500 mg dm-3, except for PUEAP, whose dose was 0 mg dm-3.