Leaf structural traits of two Restinga plant species with different resistance pattern to iron toxicity

Iron mining activities are a source of particulate iron, which contaminates soil and plants of Restinga biome (Brazil). To investigate the possible effects of iron toxicity to Ipomoea pes-caprae and Canavalia rosea leaves, plants were submitted to different exposure times (12, 36, 108 and 228 hours) and iron concentrations (0.5 or 150 mg L-1, Fe2+ as FeSO4.7H2O). After 108 hours C. rosea leaves were chlorotic while I. pes-caprae leaves presented venal chlorosis and bronzing after 228 hours, both from iron excess treatment. The anatomical alterations in I. pes-caprae were more intense and appeared earlier than in C. rosea, after 36 hours exposed to iron excess. The leaf epidermal cells of I. pes-caprae presented alterations in organization, size and shape and for both species the epicuticular wax was altered and wax rupture occurred close to the stomata. The positive staining for the presence of iron in leaf tissues matches with damaged areas in I. pes-caprae leaves, indicating direct iron toxicity. I. pes-caprae was the species with the most severe symptoms while C. rosea was the most resistant one. The results support that over time, the emission of particulate matter may negatively impact the ecological succession and biodiversity of Restinga.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author