Concurrent herbivory and metal accumulation: The outcome for plants and herbivores

• Published in: Plant-environment interactions (Hoboken, N.J. : 2018) N.J. : 2018), 2022-08, Vol.3 (4), p.170-178
• Main Authors: Godinho, Diogo P., Serrano, Helena C., Magalhães, Sara, Branquinho, Cristina
• Format: Article
• Language: English
• Subjects: Abiotic stress; Accumulation; biotic stress; Cadmium; Drinking water; elemental defense; Enzymes; Growth rate; Heavy metals; Herbivores; Herbivory; Hydrogen peroxide; Leaves; Long-term effects; Metals; Mites; Physiology; Plants; Reflectance; spectral reflectance; spider mites; Tomatoes; Toxicity; Wavelengths
• ISSN: 2575-6265; 2575-6265
• DOI: 10.1002/pei3.10088

The effects of metals on plants and herbivores, as well as the interaction among the latter, are well documented. However, the effects of simultaneous herbivory and metal accumulation remain poorly studied. Here, we shed light on this topic by infesting cadmium‐accumulating tomato plants (Solanum lycopersicum), either exposed to cadmium or not, with herbivorous spider mites, Tetranychus urticae or T. evansi during 14 days. Whereas on plants without cadmium T. evansi had higher growth rate than T. urticae, on plants with cadmium both mite species had similar growth rates, which were lower than on plants without metal. Plants were affected by both cadmium toxicity and by herbivory, as shown by leaf reflectance, but not on the same wavelengths. Moreover, changes in leaf reflectance on the wavelength affected by herbivores were similar on plants with and without cadmium, and vice versa. Long‐term effects of cadmium and herbivory did not affect H2O2 concentrations in the plant. Finally, plants infested with spider mites did not accumulate more cadmium, suggesting that metal accumulation is not induced by herbivory. We thus conclude that cadmium accumulation affects two congeneric herbivore species differently and that the effects of herbivory and cadmium toxicity on plants may be disentangled, via leaf reflectance, even during simultaneous exposure. Infestation with spider mites does not lead to higher cadmium accumulation in tomato plants, despite this metal negatively affecting the herbivores. Simultaneous exposure to metals and herbivores leads to distinct effects on plant physiology that can be detected through leaf spectral reflectance.