Work

Quantification of spatial heterogeneity of different chlorophyll fluorescence parameters over tomato leaf areas affected by Cd2+ stress

Year: 2026

Type: article

Abstract: Cadmium impairs plant growth by inducing oxidative damage through excessive ROS production. Sulfur and nitrogen supplementation can affect Cd mobility, uptake, and toxicity. This study quantifies the spatial heterogeneity of Cd-induced photochemical limitation in Solanum lycopersicum leaves using chlorophyll fluorescence imaging, and examines Cd2+ distribution in roots, stems, and leaves of hydroponic plants treated with ammonium sulfate. We assessed four treatments: control, ammonium sulfate (5 mM), cadmium (100 µM CdCl2), and their combination, using fluorescence imaging, the JIP-test, and polarography. Cd stress was intrinsically heterogeneous within single leaves, with the strongest PSII inhibition along vascular tissue and leaf tips. Contrary to expectations, ammonium sulfate failed to mitigate Cd toxicity, suggesting an adverse ammonium-Cd interaction. OJIP analysis revealed severe oxygen-evolving complex damage under combined treatment, marked by prominent K- and L-bands. These findings highlight the localised nature of Cd stress and reveal responses missed by whole-leaf measurements.

Source: Photosynthetica

DOI: 10.32615/ps.2026.035

Authors: D. GIORDANO, A. SAADATI, A.M. ASHRAFI, L. RICHTERA, M. BARTÁK