Enhanced impacts of lanthanum on organic acid accumulation and transport in tomato plants compared to yttrium

The study investigates the effects of lanthanum (La) and yttrium (Y) on the accumulation of these rare earth elements by tomato plants and their impact on organic acid profiles. Tomato seedlings were treated with varying concentrations of La and Y (0, 0.07, 0.1, 0.3, 0.5, 0.7, 1.0, and 3.0 mmol L^-1) in hydroponic solutions for 48 h. The roots' maximum La concentration reached 155.03 ± 6.20 µmol g^-1 DW, while Y showed a maximum concentration of 125.62 ± 5.02 µmol g^-1 DW. Both elements accumulated more in the roots than in the stems and leaves, suggesting a role in enhancing root metabolism and nutrient uptake. Analysis of organic acids revealed that La treatment significantly increased tartaric acid concentrations in roots, peaking at 25.37 ± 2.22 µmol g^-1 FW, and acetic acid levels reached 435.40 ± 14.82 µmol g^-1 FW. In contrast, Y treatment had a more modest effect, with formic acid levels rising from 103.38 ± 6.74 µmol g^-1 FW (control) to 169.11 ± 9.10 µmol g^-1 FW (1 mmol L^-1 Y), but there was no significant change in tartaric acid levels. These findings suggest that La more effectively stimulates specific metabolic pathways than Y. Further research is needed to explore the underlying mechanisms for sustainable agriculture practices under stress conditions.