Phytoremediation has become a promising technique for cleaning Pb-contaminated soils. Grasses have a phytoextractor potential for extracting metal from soil by transporting it and accumulating it in high concentrations in their shoots, and they have the ability to immobilize and inactivate it via phytoliths. The objective of this work was to evaluate the phytoremediation potential of forage grasses through the production of phytoliths and the occlusion of Pb in the phytoliths cultivated in Pb-contaminated soils. Three greenhouse experiments were conducted in a completely randomized design, separated by soil type (Typical Hapludox, Xanthic Hapludox and Rhodic Hapludox), in a 3 × 4 factorial scheme consisting of three forage grasses (Megathyrsus maximus, Urochloa brizantha and Urochloa decumbens) and four Pb rates (0, 45, 90 and 270 mg kg⁻¹) with four repetitions. The forage grasses were influenced by increases in the Pb concentrations in the soils. The higher Pb availability in Typic Quartzipsamment promoted Pb toxicity, as indicated by the reduced dry weights of the shoots, increased phytolith production in the shoots, increased Pb in the shoots and Pb occlusion in the phytoliths of the forage grasses. The production and Pb capture in the phytoliths in the grasses in the Pb-contaminated soils were related to the genetic and physiological differences in the forage grasses and the Pb availability in the soils. Urochloa brizantha was the most tolerant forage to the excess Pb, with a higher production of phytoliths and higher Pb occlusion in the phytoliths, making it a forage grass that can be used in the future for the phytoremediation of Pb-contaminated soils.

Diante dos expressivos desequilíbrios climáticos observados atualmente, torna-se uma necessidade revisar os impactos destas mudanças nas plantas, abordando os efeitos fisiológicos e morfológicos decorrentes de alterações nas condições atmosféricas. O aumento gradativo de gases de efeito estufa lançados diariamente na atmosfera, que se fez maior no período pós revolução industrial, afeta a fotossíntese e o crescimento das plantas, além de trazer problemas como o aumento da temperatura ao redor do mundo e crises hídricas que assolam os mais diversos países e biomas. Podemos ressaltar ainda, que o impacto de fenômenos climáticos como El Niño aflige as mais diversas culturas agrícolas, causando doenças nas plantas e perda de qualidade dos grãos. Além disso, o aumento da temperatura afeta a produtividade das plantas, enquanto a seca intensa altera ecossistemas e biomas, podendo levar à desertificação. A partir disso, foi elaborada uma revisão de literatura, com o objetivo de discutir fatores científicos que destacam a conexão intrínseca existente entre as mudanças climáticas e os seus resultados sob a biodiversidade e qualidade de vida urbana. Com isso, o estudo visa destacar a necessidade de mais pesquisas para enfrentar os desafios iminentes e garantir a sustentabilidade ambiental e alimentar. E por fim, o presente artigo pode concluir que há uma necessidade de ações urgentes, tanto biotecnológicas quanto políticas, que atuem de maneira eficaz sobre o meio ambiente visando mitigar os impactos das mudanças climáticas e preservar a biodiversidade.

The effectiveness of phytoremediation in Cd-contaminated soils is crucial for enhancing nutrient availability and plant tolerance to Cd. We simulated soil contamination with varying textures and fertilization conditions. Two experiments were conducted: one without liming and fertilization and another with soil fertilization for grasses. The soil types used were Oxisol and Entisol, and the grasses tested were Megathyrsus maximus and Urochloa brizantha at three Cd levels: 0 mg kg(-1) (Control), 2 mg kg(-1) (Low), and 12 mg kg(-1) (High). Soil amendments and fertilization did not significantly change Cd availability. Soil chemical attributes were unaffected by Cd contamination but were influenced by fertilization, which kept the pH below optimal levels. Cd availability was higher in more contaminated soils, with Entisol showing greater concentrations than Oxisol. Dry matter production of the grasses decreased with higher contamination, with U. brizantha being more productive than M. maximus in fertilized soils. Cd accumulation was higher in highly contaminated soils, particularly for U. brizantha. The bioconcentration factor was higher in Entisol, while the translocation factor exceeded 1.0 only for M. maximus in low-contamination Oxisol. Fertilization can mitigate Cd contamination effects, with U. brizantha showing greater tolerance and accumulation capacity in fertilized soils.

Phytoremediation is a technique with high viability due to its low cost and minimal environmental impact. However, there are a few results regarding the use of tropical grasses in the phytoremediation of manganese (Mn), and there is no clear definition of which extractor is more suitable for assessing Mn availability in soils. The objective of this study was to evaluate the growth potential and phytoremediation of five tropical grasses in Mn‐contaminated soil, as well as to assess the efficiency of four extractors in Mn extraction. The grass cultivars evaluated included Aruana and Tanzânia of Megathyrsus maximus, Xaraés and Marandu of Urochloa brizantha, and Basilisk of Urochloa decumbens grown in Typic Hapludox (Oxisol) amended with 0, 50, 150, and 450 mg of Mn per kg⁻¹ of soil. The experiment was conducted in a greenhouse, using a completely randomized experimental design in a 5 × 4 factorial scheme, with five replications. The experimental period lasted for 90 days. The dry matter of the shoot and root of the grasses was evaluated. Mn concentration in dry matter and its availability in soil were extracted by Mehlich‐1 and DTPA pH 7.3, while the semitotal concentration was determined by USEPA 3051 and total Mn by USEPA 3052 method. Tropical grasses showed reduced growth with increasing Mn rates in the soil, with the following sequence in the reduction in growth: Aruana > Basilisk > Marandu > Xaraés and lastly the Tanzânia. The Aruana cultivar showed greater potential for phytoextraction due to its higher ability to accumulate Mn in its biomass, followed by the Basilisk cultivar. The four different evaluated extractors were efficient in measuring Mn concentrations in the soil, with higher toxicity critical levels for the USEPA 3051 method due to the semitotal extraction nature and USEPA 3052 due to total Mn extraction. The growth of tropical grasses is reduced with increasing Mn rates applied to the soil. The Aruana of M. maximus grass has greater potential for phytoextraction of Mn‐contaminated soils, followed by Basilisk of Urochloa decumbens, Xaraés and Marandu of U. brizantha, and Tanzânia of M. maximus. The Mehlich‐1, DTPA pH 7.3, USEPA 3051, and 3052 extractors were efficient in extracting and evaluating Mn availability in soil for tropical grasses. The USEPA 3051 and 3052 methods presented higher toxicity critical levels.

Lead is an element intensively used by human activities, representing serious risks to food security due to soil contamination, making it essential to implement control strategies to mitigate its harmful effects. The objective of this study was to evaluate the influence of soil fertilization on the growth and lead accumulation of grasses used in the phytoremediation process. The experiments were conducted in a greenhouse using two soil types: Typic Quartzipsamment and a Xanthic Hapludox. A randomized block design was used in a 2 × 2 × 3 factorial scheme with three replicates, consisting of two soil types, two grasses ( Megathyrsus maximus cultivar “Mombaça” and Urochloa brizantha cultivar “Marandu”), and three levels of Pb contamination: no contamination, low contamination (45 mg kg ⁻¹ ), and high contamination (270 mg kg ⁻¹ ). The grasses were cultivated for 90 days after thinning, after which both shoot and root parts were collected for dry matter analysis and determination of Pb concentrations. Soil fertilization resulted in higher dry matter production of grasses compared to unfertilized soils, which allowed for the extraction of Pb from the soil into plant structures, increasing Pb accumulation in the grasses. The bioconcentration factor of grasses grown in fertilized soil was lower compared to unfertilized soil. U. brizantha under fertilization conditions showed greater growth even under stress, along with a high Pb accumulation in dry matter, especially in the shoots, indicating its potential as a Pb phytoextractor. On the other hand, M. maximus under fertilization conditions translocated less Pb to the shoots but exhibited a good capacity for soil extraction and root accumulation, demonstrating its potential as an alternative for Pb phytostabilization compared to U. brizantha .

Lead (Pb) is a highly toxic metal that threatens environmental and human health by impairing soil functioning and plant development and potentially entering the food chain. However, some plant species possess Pb tolerance mechanisms, making them promising candidates for the remediation of contaminated soils. This study aimed to evaluate the phytoremediation potential of Urochloa brizantha cv. Marandu cultivated in Pb‐contaminated soil microcosms by assessing its capacity for Pb absorption, accumulation, translocation, and tolerance. A greenhouse experiment was conducted using 100 dm ³ microcosms filled with Typic Quartzipsamment and four Pb levels (0, 72, 180, and 300 mg kg ⁻¹ ), under fertilization and liming conditions recommended for the species. At 180 days after the uniformity cut, the dry mass production of the aerial part and root (SDM and RDM), the concentrations and accumulation of Pb and nutrients in the soil and plant tissues, bioconcentration factor (BCF), and the translocation factor (TF) were evaluated. U. brizantha maintained biomass production under increasing levels of soil Pb contamination, demonstrating high tolerance to the metal. TF values <1, together with shoot BCF values <1, indicated restricted Pb translocation from roots to shoots and limited bioconcentration in aboveground tissues, supporting the phytostabilization potential of U. brizantha rather than its use for phytoextraction. Its high Pb tolerance and ability to maintain biomass production in contaminated soil further support its potential use in assisted revegetation strategies. However, its long‐term phytostabilization effectiveness should be confirmed by assessing root bioconcentration and changes in soil Pb mobility and availability.