Phosphorus use efficiency in anthocyanin-free tomato (Lycopersicon esculentum Mill.)

An anthocyanin-free tomato plant, H957, and its parental wild type, H883, were hydroponically grown to test for tolerance to a low phosphorus (P) in H957. The tolerance was evaluated by comparing growth and metabolism of H957 vs. H883 at different P concentrations ranging 25–400 μM. Fresh weights were measured weekly. Dry weight, mineral contents, photosynthetic rate, and P utilization ratios of the plants were measured after five weeks of growth in the hydroponic culture. Although the growth of both varieties was severely impaired at 25 μM P, H957 showed a greater fresh weight and dry weight at 50–400 μM P. H957 showed a higher net photosynthetic rate on older leaves while both varieties showed similar photosynthetic rate on young leaves. H957 tissue contains an overall lower P concentration in its tissue than H883. These observations together indicate that the anthocyaninless mutant H957 tolerate to lower P concentration. It does so by utilizing internal P with better efficiency rather than by absorbing external P better.