Morphoanatomical responses induced by excess iron in roots of two tolerant grass species

• Published in: Environmental science and pollution research international 2015-02, Vol.22 (3), p.2187-2195
• Main Authors: de Araújo, Talita Oliveira, de Freitas-Silva, Larisse, Santana, Brenda Vila Nova, Kuki, Kacilda Naomi, Pereira, Eduardo Gusmão, Azevedo, Aristéa Alves, da Silva, Luzimar Campos
• Format: Article
• Language: English
• Subjects: aerenchyma; Analysis; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Cell Wall - metabolism; cell walls; Chemical contaminants; color; Contaminants; cortex; Detoxification; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Grasses; Iron; Iron - metabolism; Iron - toxicity; iron absorption; Iron compounds; Medical prognosis; Metals; Microscopy, Electron, Scanning; nutrient solutions; Paspalum - drug effects; Paspalum - metabolism; Paspalum - ultrastructure; phenolic compounds; Phenols; Plant Roots - drug effects; Plant Roots - metabolism; Plant Roots - ultrastructure; Plant tolerance; Plants; Poaceae; Pollution; Pollution monitoring; Research Article; Roots; Setaria parviflora; Setaria Plant - drug effects; Setaria Plant - metabolism; Setaria Plant - ultrastructure; sieve elements; Studies; Toxicity; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-014-3488-1

We aimed to verify whether morphoanatomic alterations occur in response to excess iron, in roots of Setaria parviflora and Paspallum urvillei (Poaceae), and to localize the presence of the sites of iron accumulation. Plants were subjected to 0.009, 1, 2, 4, and 7 mM Fe-EDTA in nutrient solution. Both species presented iron contents in the roots above the critical toxicity level. The presence of iron plaque on roots of the two species was confirmed, and it may have reduced iron absorption by the plants. Roots from the two species showed typical visual symptoms of stress by excess iron: change in color and mucilaginous and flaccid appearance. Anatomical damage was observed in both species: aerenchyma disruption, alterations in endodermal cells, and irregular shape of both vessel and sieve tube elements. The metal was histolocalized in the cortex and in protoxylem and metaxylem cell walls in both species, which suggests a detoxification strategy for the excess iron. Phenolic compounds were not histolocalized in roots. Microscopic analyses were therefore effective in evaluating the real damage caused by excess iron.