Impact of long-term cadmium exposure on mineral content of Solanum lycopersicum plants: Consequences on fruit production

• In fruit pericarp Cd increased between the early development stage and late ripening stages.
• Cadmium toxicity altered plant contents of macronutrients.
• Cadmium affected micronutrient distribution in plant tissues.
• Cadmium effects on fruit mineral contents were more pronounced at 25 DPA than at ripening stages.

In young tomato plants, modifications in mineral composition by short-term cadmium (Cd) treatments have been extensively examined. However, long-term Cd treatments have been fewly investigated, and little information about Cd-stress in fruiting plants is available. In the present work, we examined the changes in mineral nutrients of roots, stems, leaves, flowers, seeds and fruit pericarp of tomato plants submitted to a long-term Cd stress. After a 90-day culture period in hydroponic contaminated environment (0, 20 and 100 μM CdCl2), fruit production was affected by increasing external Cd levels, with the absence of fruit set at 100 μM Cd. Meanwhile, Cd altered the plant mineral contents with an element- and organ-dependent response. At 20 μM, Cd triggered a significant increase in Ca content in roots, mature leaves, flowers and developing fruits. However, at 100 μM Cd, Ca content was reduced in shoots, and enhanced in roots. Cd stress reduced Zn and Cu contents in shoots and increased them in roots. High Cd level led to a significant decrease in K and Mg content in all plant organs. Furthermore, Fe concentration was reduced in roots, stems and leaves but increased in flowers, seeds and red ripe fruits. Our results suggest that tomato plants acclimatize during long-term exposure to 20 μM Cd, while 100 μM Cd results in drastic nutritional perturbations leading to fruit set abortion.