Cadmium toxicity degree on tomato development is associated with disbalances in B and Mn status at early stages of plant exposure

The sweet side of misbalanced nutrients in cadmium‐stressed plants

“…Leaves of both tolerant and sensitive tomato accessions had an increased Mn concentration after 6 days of Cd exposure, despite no additional Mn supplementation (Figures and ). Since all tomato genotypes exhibited concurrent decreases in the root Mn concentration (Carvalho et al, ; Carvalho, Piotto, Franco, et al, ), the data indicate that plants might actively manage Mn distribution among their organs, favouring its accumulation in leaves as a potential protective strategy against Cd toxicity. Consistently, the overexpression of CsMTP9 , which encodes a plasma membrane involved in the Mn 2+ efflux from root cells, confers increased resistance of A. thaliana plants to Cd excess while enhancing translocation of Mn from roots to shoots (Migocka et al, ).…”

“…Roots, which generally have higher Cd concentrations than do shoots (Kato, Carvalho, Gaziola, Piotto, & Azevedo, ; Piotto et al, ), should be able to quickly activate protective mechanisms to counteract the entrance of positive charges originating from Cd accumulation. One of these mechanisms is probably associated with reducing concentrations of positively charged nutrients in roots; this mechanism can involve enhancing translocation of Mn (and also Zn) from roots to shoots (Borges et al, ; Carvalho, Piotto, Franco, ; Carvalho et al, ) (Figures and ) and may be further potentiated by either decreasing uptake (Carvalho, Piotto, Gaziola, et al, ) or increasing exclusion in the root system. A decreased Mn concentration was observed in roots of Brassica campestris accessions, which improved plant biomass after being subjected to Cd exposure (Zhu, Sun, Fang, Qian, & Yang, ).…”

“…The ratios of the values from Cd‐stressed plants over control plants for each accession are represented on the y axis. Based on Carvalho, Piotto, Franco, et al () and Carvalho et al ()…”

“…Reprogramming Mn and B status in Cd‐stressed plants, however, does not come without cost. Its advantages are limited by the toxicity of high Mn and B concentrations (Carvalho et al, ; Carvalho, Piotto, Franco, et al, ), particularly in leaves (Figures and ). Too high concentrations can damage leaves or their parts, leading to decreased biomass production (Raza et al, ).…”

“…Tropic Two Orders (TTO), accession CNPH0920 (C20) and S. pimpinellifolium accession LA0122 (LA0). Graph a uses unpublished data that come from Carvalho, Piotto, Franco, et al () and Carvalho et al (), respectively. Graph b is based on Carvalho, Piotto, Franco, et al () and Carvalho et al ()…”