Editorial: Costs and tradeoffs in plant adaptation and acclimation to metals

COPYRIGHT © 2023 Muszyńska, Rossini-Oliva and Wiszniewska. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Editorial PUBLISHED 24 July 2023 DOI 10.3389/fpls.2023.1245426

into the mechanism of Hg phytostabilization, may facilitate further studies on phytoremediation.
The role of quercetin (Qu) in ameliorating chromium (Cr) toxicity was evaluated by Aslam et al. in fenugreek (Trigonella corniculata). The seeds were primed with various doses of Qu prior to Cr treatment. Cr toxicity in non-primed plants was manifested by reduced biomass accretion, lower photosynthetic efficiency, and significant oxidative stress. The study revealed that a concentration of 25 µM Qu significantly improved growth parameters, as well as several biochemical characteristics, such as protein, fiber, and flavonoid content, proline accumulation and concentration of photosynthetic pigments. Interestingly, plants benefited from Qu application also in non-stressful conditions, without exposure to Cr. In the presence of Cr, the most pronounced effect of Qu priming was the elevated activity of antioxidant enzymes. In conclusion, the Authors proposed to test the Qu effect also for other abiotic stresses, as this is a non-harmful compound that may accelerate plant recovery in stressful conditions.
Another approach to mitigate metal toxicity was tested by El-Okkiah et al. in pea (Pisum sativum). They employed foliar application of silicon (Si) to improve plant growth in the soil contaminated with cadmium (Cd), and to evaluate its effects on anatomical and biochemical features. The authors conducted data modelling with the use of an artificial neural network to get an insight into the mechanisms of Cd-Si interactions. They revealed that Si ameliorated Cd-induced disturbance in organ anatomy, increasing lignification and other modifications of the cell walls due to deposition of Si inside root cortex cells. Additionally, Si contributed to the widening of metaxylem vessels and pith thickness. These adaptations could restrict Cd translocation to the shoots, thus improving overall growth performance in pea plants. Si was also found to boost the activity of antioxidant enzymes and alleviate oxidative damage. This relatively cheap method of crop protection may bring crop yield improvement in contaminated areas.
In the study of Tan et al. on pakchoi (Brassica chinensis), an interesting relationship was elucidated between chloroplast biogenesis (indirectly related to photosynthetic efficiency), ascorbate-glutathione (AsA-GSH) cycle and dose of lead (Pb) present in the soil. Increasing Pb concentrations caused a progressive reduction of the activity of enzymes involved in the AsA-GSH cycle, as well as a decrease in the content of reduced forms of ascorbic acid and glutathione. These changes contributed to the inhibited expression of genes involved in chloroplast development and were manifested in the disturbed structure of chloroplasts, including membranes and stromal sheets, particularly under higher Pb concentrations. These findings broaden current knowledge on the interconnection between photosynthetic apparatus and antioxidant machinery under Pb toxicity.
In summary, the published articles in our Research Topic are in accordance with Paracelsus's statement 'Omnia sunt venena, nihil est sine veneno. Sola dosis facit venenum', and indicate dose-and timedependent effects of metallic trace elements on plants. They represent valuable contributions to deciphering plant ability to repair metalinduced damage and describing the networks that make the life of stressed plants easier. Although the tested variety of both metals and priming agents, the general conclusion of all research clearly highlights the crucial role of antioxidant machinery in plant survival under metal exposure. We hope that the results of the presented experiments will be an inspiration for further research in this field, and will facilitate the development of novel solutions against the progressive heavy metal contamination of the environment.

Author contributions
EM and AW wrote the manuscript. All authors revised the manuscript and gave final approval for publication.