The Atlantic Forest is a biome that has suffered anthropic actions, such as the extraction of hardwood, which can lead to the extinction of endemic species of great economic and ecological value, such as Dalbergia nigra. In this perspective, large-scale multiplication studies are necessary to contribute to the conservation of this species. The objective of this work was to establish a protocol for the in vitro production of axenic seedlings of D. nigra. Four experiments were performed: I. Immersion times in NaOCl. II. Disinfecting agents in seed germination of D. nigra. III. NaOCl toxicity in seeds of the model species Lactuca sativa L. IV. Culture media and glutamine in the germination and initial growth of D. nigra. All experiments were arranged in a completely randomized design. For a better disinfestation and less harmful effects to the seedlings, it is recommended that the seeds be treated with 70% alcohol (1 min) and NaOCl (14 min). NaOCl has a high phytotoxic, cytotoxic, and genotoxic effect, and its mechanism of action in the L. sativa cell cycle is clastogenic and aneugenic, suggesting the formation of abnormal seedlings in D. nigra. The WPM medium and its supplementation with glutamine (0.75 mg.L-1) are recommended.

Plants have developed several dormancy mechanisms essential for resilience in adverse environments. Understanding these mechanisms allows for the development of weed control strategies and enhances seedling production. This study aimed to investigate the anatomical and ecophysiological mechanisms associated with seed coat impermeability and physical dormancy in Mimosa camporum Benth. and other Amazonian Mimosa L. species, emphasizing their effects on water uptake, germination behavior, and ecological adaptation. For M. camporum, the imbibition curve, seed coat anatomy through scanning electron microscopy, and germination tests of seeds subjected to chemical scarification (H₂SO₄) were determined. Data from 25 Amazonian Mimosa species were compiled for ecological and physiological characterization, with subsequent Multiple Correspondence Analysis. Immersion in H₂SO₄ for 5 min is adequate to break dormancy in Mimosa camporum Benth. seeds. In Mimosa camporum Benth., sulfuric acid scarification effectively promoted water uptake and germination, demonstrating the close relationship between seed anatomy, imbibition behavior, and dormancy regulation. Physical dormancy in Amazonian Mimosa L. species is directly associated with seed coat impermeability, especially the presence of macrosclereids in the palisade layer. In the Amazon, the reproductive success and resilience of Mimosa L. species are related to the physical dormancy and desiccation tolerance of their seeds.

Volumetric models are a crucial tool for forest management. The study aimed to adjust the mixed model by Schumacher and Hall for estimating commercial volume in a dense ombrophilous forest situated in Ferreira Gomes, Amapá, Brazil. Cubage data from 100 sample trees of 5 species were used to adjust the Schumacher and Hall model in fixed and mixed non-linear forms with the diameter class as a random effect. In addition, the same model was also adjusted for each class to verify whether good equations will be generated by stratifying by diameter class. After analysis, it was found that most of the equations by diameter class do not present all significant parameters. On the other hand, the mixed models using class as a random effect showed good results. Finally, it can be seen that mixed models are a much better alternative than stratification by diameter class for volume estimation.

O Brasil possui mais de 10% do território composto de Terras Indígenas, Áreas Quilombolas e Unidade de Conservação visando a conservação da biodiversidade in situ. Entretanto, para a maioria das espécies não há estratégia de conservação ex situ via sementes. Desta forma, o objetivo do presente trabalho é a avaliação da tolerância à dessecação e armazenamento de sementes de Erythroxylaceae da Amazônia. Uma revisão de literatura on line foi realizada com os seguintes termos, nas Línguas Portuguesa, Espanhola e Inglesa: “sementes Erythroxylaceae”, “armazenamento Erythroxylaceae”, “secagem Erythroxylaceae”, “sementes Erythroxylum”, “armazenamento Erythroxylum”, “secagem Erythroxylum”. Houve registro de informações sobre a tolerância à dessecação ou armazenamento de sementes ou conservação de sementes para apenas 12 espécies. A maioria das espécies de Erythroxylaceae da Amazônia apresentam teores de água acima de 45% após dispersão natural de suas sementes. Em sementes recentemente coletadas, a porcentagem de germinação de sementes está acima de 54%, exceto para as espécies E. deciduum A.St.-Hil. (3,7%) e E. campestre A.St.-Hil. (2,0%). Independente das formas de armazenamento, a perda de água reduz ou inviabiliza a germinação de suas sementes. As espécies da família Erythroxylaceae da Amazônia possuem sementes caracteristicamente recalcitrantes, ou seja, sensíveis a dessecação/secagem.

Aspectos morfo-anatômicos do fruto, semente e desenvolvimento pós-seminal e emergência de plântulas de mari ( Poraqueiba paraensis Ducke) - DOI:10.5039/agraria.v13i1a5508