Mining contributes significantly to the world's economy. However, it brings strong environmental impacts, including the destruction of the original vegetation. In this way, the recovery of degraded areas by mining has been a mandatory procedure in many countries. With the objective to review this subject, a bibliometric analysis was carried out using scientific articles published in the period 1990-2018. A total of 700 articles in 171 journals were sampled. Ecological Engineering and Restoration Ecology were the journals with the largest number of articles. There was a significant increase of articles along time approaching the use of geotechnologies and arbuscular fungi. Recovered or recovering ecosystems were studied in 45 countries, mainly in Brazil, Australia, USA, China, and Spain. Coal and bauxite were the most common resources mined. The most frequent recovery methods were: seedling planting, direct seeding, natural regeneration, and hydroseeding, with techniques employed in some of them. In 35.71% of the articles, a small number of species (2-5) were used for the initial plant's establishment. The number of articles decreased as the number of both, plant species used in the initial recovery phase, and ecosystem's age increased. In monitoring, the most important indicators were classified as functional or functional plus structural. From the functional indicators, the Technosols or rebuilt soils were the most evaluated. Future perspectives on forests recovery includes methods tailored to peculiar features (soil and economic) of each ecosystem. For the forest recovery monitoring, the use of geotechnologies, mainly the Unmanned Aerial Vehicles (UAVs), as well as wildlife indicators tend to increase rapidly.

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Water deficit is the most limiting abiotic stress to plants because it affects several physiological and biochemical processes. Brassinosteroids, including 24-epibrassinolide (EBR), are steroids that regulate growth and positively act on gas exchange. This research aims to determine whether EBR can attenuate the negative effects of water deficit, revealing possible contributions of this steroid on photosynthetic machinery of young Eucalyptus urophylla plants under water deficit. The experiment had a completely randomized factorial design with two water conditions (control and water deficit) and three levels of EBR (0, 50, and 100 nM EBR). Water deficit caused a decrease in the levels of total chlorophyll and carotenoids, but these photosynthetic pigments increased by 135 and 226%, respectively, in plants sprayed with EBR when compared to the water deficit + 0 nM EBR treatment. Regarding the antioxidant system, 100 nM EBR induced significant increments in superoxide dismutase (42%), catalase (52%), ascorbate peroxidase (147%), and peroxidase (204%).Steroid application in E. urophylla plants exposed to water deficit increased the effective quantum yield of the photosystem II (PSII) photochemistry and electron transport rate. However, interestingly, it decreased the nonphotochemical quenching and relative energy excess at the PSII level, indicating improvements related to PSII efficiency. This research revealed that application of 100 nM EBR attenuated the negative effects caused by water deficit, being explained by the positive repercussions on antioxidant enzyme activities, chloroplastic pigments, PSII efficiency, electron flux, and net photosynthetic rate. | INTRODUCTIONThe genus Eucalyptus has more than 700 species, distributed across more than 20 million hectares of the world's temperate and tropical regions (Mora et al.

& Key message Our research revealed that 24-epibrassinolide alleviated nickel toxicity in young Eucalyptus urophylla plants, inducing benefits on nutritional, physiological, biochemical, anatomical and morphological responses. & Context Soil contamination by heavy metals may limit the Eucalyptus production. Disturbances caused by nickel (Ni) toxicity interfere with the absorption of other essential nutrients. 24-Epibrassinolide (EBR) is one form of brassinosteroid (BR) that provides benefits for plant metabolism under Ni toxicity. & Aims The aim of this study was to determine whether exogenous EBR can improve ionic homeostasis by evaluating nutrient concentrations, anatomical characteristics and chlorophyll fluorescence in young Eucalyptus urophylla plants subjected to Ni toxicity. & Methods The experiment was randomized into four treatments, including two Ni concentrations (0 and 600 μM Ni) and two 24epibrassinolide concentrations (0 and 100 nM EBR). & Results EBR significantly reduced Ni contents. Plants exposed to Ni 2+ and sprayed with steroid had increases in the Ca 2+ /Ni 2+ and Mn 2+ /Ni 2+ ratios in the leaves of 38% and 15%, respectively, compared with the same treatment without EBR. The treatment of Ni 2+ toxicity + EBR presented an increase of 42% in effective quantum yield of PSII photochemistry, when compared with plants exposed to Ni without EBR. Ni toxicity induced negative effects on stomatal functionality, but EBR application mitigated these effects. & Conclusion Benefits on effective quantum yield of PSII photochemistry after EBR spray can be related to increases in manganese contents. EBR reduced oxidative stress, alleviating the deleterious effects induced by Ni toxicity and inducing positive repercussions on antioxidant enzymes, photosynthetic pigments and biomass.