Selenium is beneficial to plants and is essential for animals and humans, which justifies any efforts for producing Se-enriched wheat grains worldwide. This study aimed to (i) verify if wheat is an efficient species to be used for Se biofortification in tropical agroecosystems and (ii) assess the influence of Se on the physiological and biochemical parameters of wheat plants. Selenium was applied as sodium selenate (Na₂SeO₄) at different doses (12, 21, 38, 68, and 120 g ha⁻¹) in soil. The dose of 120 g ha⁻¹ of Se resulted in Se contents of 7.98 and 2.27 mg kg⁻¹ in the leaves and grains, respectively. The supply of 38 g ha⁻¹ of Se increased the total soluble sugar content by 50%, with reducing sugars increasing by 17% and sucrose augmenting 53%, compared with that in the control. The doses of 12, 68, and 120 g of Se ha⁻¹ promoted a significant increase in catalase activity. In addition, Se application increased carbohydrate and nutrient contents. Our findings indicate that wheat is a good species for agronomic biofortification with Se via soil application in tropical agroecosystems. Selenium proved to be a valuable element for plants since it provides physiological and biochemical benefits.

Climate change causes increasingly longer periods of drought, often causing the death of plants, especially when they are in the early stages of development. Studying the benefits provided by arbuscular mycorrhizal (AM) fungi to plants in different water regimes is an efficient and sustainable strategy to face climate change. Thus, this study investigated the influence of AM fungi on Handroanthus serratifolius seedlings under different water regimes, based on biochemical, and nutritional growth parameters. The experiment was carried out in H. serratifolius seedlings cultivated with mycorrhizas (+AMF) and without mycorrhizas (-AMF) in three water regimes; a severe water deficit (SD), a moderate water deficit (MD), and a well-watered (WW) condition. AM fungi provided greater osmoregulation under water deficit conditions through the accumulation of soluble sugars, total free amino acids, and proline, as well as by reducing sugar. The increase in the absorption of phosphorus and nitrate was observed only in the presence of fungi in the well-watered regimen. A higher percentage of colonization was found in plants submitted to the well-watered regimen. Ultimately, AM fungi promoted biochemical, nutritional, and growth benefits for H. serratifolius seedlings under the water deficit and well-hydrated conditions, proving that AMF can be used to increase the tolerance of H. serratifolius plants, and help them to survive climate change.

The low availability of phosphorus and water in soil can promote the remobilization of carbohydrates in the plant, releasing energy to mitigate stress. In this context, our objective was to analyze the production and allocation of carbohydrates in plants of Carapa guianensis Aubl. submitted to different doses of phosphate fertilization, during the rainy and dry seasons, in the western region of Pará. We used three phosphorus dosages (0, 50, 250 kg ha⁻¹) as treatments. We evaluated the plants during the dry and wet seasons. We quantified dry matter production, phosphorus content, total soluble sugars, reducing sugars, sucrose, and starch. Phosphate fertilization and different evaluation periods influenced carbohydrate concentrations (p < 0.05) in plants. The highest levels of P in the leaves were registered in October and, in the roots the content decreased with the passage of time in all treatments. The control had higher dry matter production in leaves and stems. During the dry season, there was an accumulation of carbohydrates in plants and a low production of dry matter. Soluble sugars and sucrose tended to be allocated to the stem, reducing sugars to the leaves and starch to the roots, in most periods. In general, C. guianensis seedlings were not very responsive to phosphorus addition.

Resíduos de peixe podem ser compostados, gerando biofertilizantes (BFRP) cujo efeito no cultivo de hortaliças na Amazônia é pouco investigado. Esse estudo avaliou a eficácia fitotécnica do BFRP de pescada branca no cultivo do coentro “Verdão”, preparando cinco substratos de cultivo, com diferentes quantidades ou tipos de fertilizantes, aplicados em duas parcelas iguais. Esses substratos foram dois testes (com 1,99 [T1] e 0,93 [T2] % de BFRP), um controle negativo (sem fertilizante, T3), um controle positivo químico (NPK 10:10:10, T4) e um controle positivo orgânico (cama de frango, T5). Sementes foram inoculadas nesses substratos, e as plântulas/plantas observáveis foram avaliadas quanto aos fatores emergência, sobrevivência e altura. Todos os substratos apresentaram elevada taxa de emergência, porém somente aqueles com BFRP apresentaram índi-ce superior a 90%. Em relação à sobrevivência, observou-se melhor desempenho naqueles com BFRP, especialmente T2 com 92%, enquanto T4 apresentou queda acentuada após a segunda parcela de fertilizante. Quanto à altura, os substratos teste foram superiores em todas as biometrias, especialmente T1, com 10,67 cm maior comparado ao T4. Portanto, o BFRP amazônico é mais eficiente do que os fertilizantes tradicionais no cultivo de coentro Verdão.

Lettuce (Lactuca sativa L.) is a widely consumed leafy vegetable cultivated globally, particularly under soilless systems to enable intensive and high-efficiency production. In these systems, precise nutrient solution management is essential, especially regarding calcium, an indispensable macronutrient involved in cell wall stabilization, membrane integrity, root development, and physiological responses to stress. This study evaluated the morphological and nutritional performance of crisp lettuce cultivars Mônica SF 31 and Veneranda grown using a nutrient film technique (NFT) system, using Calcário, Lithocal^®, and LT Supra^® as alternative calcium sources, alongside a control treatment. The experiment followed a randomized block design in a 4 × 2 factorial arrangement. Measured variables included root, leaf, and stem dry mass; stem length and diameter; and nutrient accumulation and gas exchange parameters. Data were subjected to analysis of variance and means were compared using Scott-knott test. Calcium supplementation significantly increased plant growth, with leaf fresh mass rising by 37% and root fresh mass by 56% compared to the control. Foliar calcium and magnesium concentrations were effectively enhanced by the treatments. Calcário, Lithocal^®, and LT Supra^® demonstrated effectiveness as calcium sources in soilless lettuce cultivation, promoting improved nutrient accumulation—particularly calcium and magnesium—and substantial gains in fresh biomass and root system development. Calcium supplementation is therefore recommended as a strategy to enhance productivity and crop quality in intensive soilless systems.

Zinc (Zn) is an essential micronutrient for plant development, playing various physiological roles including photosynthesis, sugar formation, protein synthesis, fertilization, seed production and d...