How does drought affect native grasses’ photosynthesis on the revegetation of iron ore tailings?

• Published in: Environmental science and pollution research international Vol. 28; no. 12; pp. 14797 - 14811
• Main Authors: Rios, Camilla Oliveira, Siqueira-Silva, Advanio Inácio, Pereira, Eduardo Gusmão
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2021; Springer Nature B.V
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Catalase; Conductance; Drought; Droughts; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Grasses; Hydrogen Peroxide; Iron; Iron compounds; Iron ores; Leaves; Malondialdehyde; Mine tailings; Moisture content; Oxidative stress; Paspalum densum; Photochemicals; Photosynthesis; Photosystem II; Plant growth; Plant Leaves; Recovery; Rehydration; Research Article; Resistance; Revegetation; Species; Stomata; Stomatal conductance; Substrates; Tailings; Transpiration; Waste Water Technology; Water; Water availability; Water content; Water deficit; Water Management; Water Pollution Control; Water stress; Water use; Water use efficiency; Mining; Revegetation; Oxidative stress; Water stress; Setaria parviflora; Paspalum densum
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-11599-x

The revegetation of areas degraded by iron ore mining is a difficult challenge mainly due to water availability and impoverished metal-rich substrates. We sought to understand the photosynthetic responses to drought of native tropical grasses Paspalum densum (Poir.) and Setaria parviflora (Poir.) grown in iron ore tailing. The grass P. densum presented better photosynthetic adjustments when grown in the iron ore tailing and S. paviflora in response to water stress. Both species accumulated iron above the phytotoxic threshold when grown in an iron ore tailing. The net photosynthesis, stomatal conductance, transpiration, and water use efficiency decreased followed by a reduction in leaf relative water content in response to water stress for both species. The photochemical efficiency of photosystem II only decreased at the point of maximum drought. At this point, the water-stressed grass grown in the iron ore tailing presented higher H 2 O 2 concentrations, particularly S. parviflora . After rehydration, full recovery of photosynthetic variables was achieved with decreased malondialdehyde concentrations, increased catalase activity, and, consequently, decreased H 2 O 2 concentrations in leaves for both species. The fast recovery of the native grasses P. densum and S. parviflora to drought in the iron ore tailing substrate is indicative of their resistance and potential use in the revegetation of impoverished mined areas with high iron content and seasonal water deficit.