Respostas ecofisiológicas e bioquímicas de plantas jovens de Ochroma pyramidale (cav. ex lam) urb. submetidas à deficiência hídrica e alagamento.

O objetivo da pesquisa foi avaliar os efeitos da deficiência hídrica e do alagamento nos comportamentos fisiológicos e metabólicos do carbono e nitrogênio em plantas jovens de pau-de-balsa (Ochroma pyramidale). Para isso foi conduzido um experimento em casa-de-vegetação da Universidade Federal Rural da Amazônia, Campus de Capitão/Poço, em julho de 2013. Utilizado o delineamento experimental inteiramente casualizado em esquema fatorial (3x4) em três condições hídricas: controle (irrigado), deficiência hídrica e alagamento, em quatro períodos (0, 4, 8 e 12 dias), com 5 repetições, totalizando 60 unidades experimentais. As variáveis fisiológicas avaliadas foram: Potencial Hídrico de Antemanhã, (Ψam); Condutância Estomática, (gs) e Transpiração, (E); As variáveis bioquímicas foram: Ácido Abscísico, Teores de Amido, Carboidratos Solúveis Totais, Sacarose, Nitrato, Atividade da Redutase do Nitrato, Teores de Amônio Livre, Atividade da Glutamina Sintetase, Aminoácidos Solúveis Totais, Proteínas Solúveis Totais, Teores de Prolina e Glicina Betaína. O potencial hídrico antemanhã e as trocas gasosas decresceram significativamente ao longo do tempo nas plantas sob estresse hídrico, enquanto que as concentrações de Ácido Abscísico aumentaram nas plantas sob deficiência hídrica e alagamento. Já os teores de amido ecresceram tanto nas plantas sob deficiência hídrica quanto nas em alagamento representando uma queda de 2,06 e 8 vezes respectivamente, quando comparado as plantas controle. O conteúdo de carboidratos solúveis totais e sacarose aumentaram nas plantas sob deficiência hídrica representando 1,65 e 1,54 vezes, quando comparado as plantas controle. O mesmo não ocorrendo com as plantas sob alagamento para as mesmas variáveis onde decresceram em torno de 2 e 6,93 vezes respectivamente. Os teores de nitrato, atividade da redutase do nitrato e glutamina sintetase reduziram significativamente nas plantas sob estresse hídrico ao longo do tempo, fato não observado nas concentrações de amônio livre que aumentou significativamente. As concentrações de aminoácidos, glicina betaína e prolina aumentaram nas plantas sob deficiência hídrica, entretanto na condição de alagamento essas variáveis decresceram consideravelmente a partir do 4º dia. Os teores de proteínas decresceram nas plantas sob deficiência hídrica e alagamento. Contudo, a pesquisa concluiu que as condições sob deficiência hídrica e alagamento por um período de doze dias foi o suficiente para alterar os processos fisiológicos e metabólicos das plantas de pau-de-balsa.The objective of the research was evaluates the effects of water deficit and the flooding in the physiological and metabolic behaviors of the carbon and nitrogen in young plants of balsa wood (Ochroma pyramidale). For this was carried out an experiment on a greenhouse of the Universidade Federal Rural da Amazônia, Capitão Poço campus, on July, 2013. Was used a completely randomized desing on factorial scheme (3x4) on three water conditions: control (irrigated), water deficit and flooding, in four periods (0, 4, 8 and 12 days), with five replications, totaling 60 experimental units. The physiological variables evaluated were: predawn water potential, (Ψam); stomatal conductance, (gs) and transpiration, (E). The biochemical variables were: abscisic acid, contents of starch, total soluble carbohydrate, sucrose, nitrate, nitrate reductase activity, contents of free ammonium, glutamine synthetase, total soluble amino acids, contents of proline and glycine betaine. The predawn water potential and the gas exchanges decreased significantly over time in the plants under water stress, while abscisic acid increased in the plants under water deficit and flooding. The contents of starch decreased as in the plants under water deficit as in the plants under flooding, representing a down to 2,06 and 8 times respectively , when compared to control plants. The contents of total soluble carbohydrate and sucrose increased in the plants under water deficit, representing 1,65 and 1,54 times, when compared to control plants; Which did not occur with plants under flooding to the same variables that decreased around to 2 and 6,93 times respectively. The contents of nitrate, nitrate reductase activity and glutamine synthetase decreased significantly in the plants under water stress over time, fact not observed in the free ammonium concentrations that increased significantly. The concentrations of amino acids, glycine betaine and proline increased in the plants under water deficit. However, in the flooding condition these variables decreased substantially from the fourth day. The contents of proteins decreased in the plants under water deficit and flooding. However, the research concluded that the conditions of water deficit and flooding for a period of twelve days were enough to change the physiological and metabolic process of the plants of balsa wood

Effect of salicylic acid on cowpea seedlings under saline stress

The aim of this work was applying salicylic acid (SA) in cowpea seedlings under saline stress. The experiment took place in the seed laboratory of the Universidade Federal Rural da Amazônia with a completely randomized experimental design in a 2 x 2 x 3 factorial scheme, with two bean cultivars (Canapu and Pingo-de-ouro), two levels of salicylic acid (0, and 0.50 mM) and three salt stress levels (0, 25, 50 mM). The seeds were previously soaked in salicylic acid (0 and 0.50 mM) for a period of 12 hours and then placed in germitest paper rolls for treatments with NaCl (0, 25, 50 mM) for a period of 12 days at room temperature constant 27 °C. There was a significant effect of cultivars, AS dose and NaCl concentrations and their interactions on most of the analyzed variables. Root and leaf proline concentrations were higher in pingo-de-ouro cultivar, Canapu cultivar had better performance in biomass accumulation. Salicylic acid reduced proteins in the leaves by 13.33%, while in the root there was an increase of 12.61%, ammonium concentrations reduced in the roots by 11.9%. When applied to salinity (25 and 50 mM) there was an increase of proteins in the leaves 40.83% and 27.48% respectively, and a reduction of amino acids of 30.24 and 25.24% in NaCl dosages (25 and 50 mM) respectively. Salinity reduced biomass accumulation and interfered with cellular solute production. However, the application of salicylic acid promoted salt stress tolerance in Canapu cultivar

Chlorophyll, nitrogen and antioxidant activities in Cumaru (Dipteryx odorata (Aubl.) Willd) (Fabaceae) in two water regimes

The Cumaru (Dipteryx odorata (Aubl.) Willd.) is a species used by traditional populations and industries using timber and non-timber forest products. This study aimed to analyze the levels of chlorophyll A, B, total ammonia levels, nitrate, proline, electrolyte leakage and activity of oxidative enzymes in evaluation to tolerance of cumaru plants subjected to drought for 21 days of stress. The experiment was conducted in a greenhouse at the Federal Rural University of Amazonia (UFRA), Belém, Pará, in the period from March to July 2015. The results showed a significant decrease in the relative water content of 50.8 and 55% for chlorophyll b, 45% to total chlorophyll and an increase in proline to the plants under drought. There was no significant difference to chlorophyll a, ammonium and nitrate. Increases in electrolyte leak with 22.74% for roots and 39.55% for leaves were observed. The enzyme catalase (CAT) showed a significant increase from the 14th day of the experiment, while changes in superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities were observed from the 7th day of the experiment. Cumaru plants are not drought tolerant over 21 days; also, young plants of cumaru respond negatively to conditions of low water availability in the soil.Key words: Drought, oxidative stress, chlorophyll, tolerance, Dipteryx odorata

Characterization of biochemical behavior of sorghum (Sorghum bicolor [Moench.]) under saline stress conditions using multivariate analysis

The aim of this research was to characterize the biochemical behavior of sorghum plants under saline stress using multivariate statistical analysis methods for efficient management of Sorghum bicolor [Moench.]). The experimental design was completely randomized design composed of three saline concentrations (0, 1.5 and 2.0 M) in 10 replications. In the multivariate analysis (hierarchical method), there were distinct and sub-groups in the sorghum plant treatments. Group 1 consisted of the root parts and under this group there were two subgroups: 1.5 to 2.0 concentration (Group 1) and 2 concentration (Group 2). The increase of NaCl concentration in the roots and leaves has inverse correlation with decrease of nitrate reductase, amino acids, protein and starch. The amounts of amino acids, carbohydrates, sucrose and proline in the roots and carbohydrates, sucrose and proline in the leaves of sorghum plants are reliable biological indicators of saline stress conditions in the soil. The nitrate compound differed (p ≤ 0.05) in the sorghum plant roots; it had an average value of 0.04 μmol kg-1 of nitrate in the control treatment dry matter. The nitrate average was between 0.04 and 0.06 μmol kg-1, but without statistical difference for all concentrations.Key words: Multivariate statistics, salt concentration, proline, carbohydrate

Como o estresse nutricional do solo limita a restauração na Amazônia? : Respostas fisiológicas, bioquímicas e anatômicas de espécies arbóreas

Forest restoration is an urgent demand in the national and global scenario, especially in the Amazon due to the advance of forest cover loss. On the other hand, the nutritional limitation of soils in this biome is a challenge for this practice, considering the entire impact of stress on plants. Considering it, this review sought to compile the findings on the impacts of nutritional stress on tree species, as well as the strategies used to reverse this impasse in the Amazon. As a result, it was possible to observe biochemical, physiological, and morphological responses in tree species. In general, we found that nutritional stress results in changes in the biochemical and physiological activities of the plant since most nutrients are related to the function, structure, and/or composition of cellular elements. For morphological characteristics, a decrease in height, biomass and leaf area are the most recurrent damages. Regarding restoration methods used to minimize nutritional stress, besides conventional techniques such as phosphate fertilization and liming, it was observed the scientific community has invested in strategies mainly based on the reuse of waste. Furthermore, the application of biostimulants, biochar, and biofortification is increasingly common and promising. In this context, the promotion of research in the Amazon biome is strongly recommended to reduce existing gaps.A restauração florestal é uma demanda urgente no cenário nacional e global, especialmente na Amazônia devido ao avanço da perda de cobertura florestal. Por outro lado, a limitação nutricional dos solos do bioma é um gargalo para esta prática, tendo em vista uma série de impactos causados pelo estresse às plantas. Diante disso, está revisão buscou compilar os achados sobre os impactos do estresse nutricional para espécies arbóreas, bem como as estratégias utilizadas para reverter este impasse na Amazônia. Por meio da revisão, foi possível observar respostas bioquímicas, fisiológicas e morfológicas em espécies arbóreas. De maneira geral, constatou-se que o estrese nutricional resulta nas alterações de atividades bioquímicas e fisiológicas do vegetal, já que a maioria dos nutrientes constituem funções relacionadas à função, estrutura e/ou composição de elementos celulares. Para as características morfológicas, decréscimo em altura, biomassa e área foliar são os prejuízos mais recorrentes. Em relação aos métodos de restauração utilizados para minimizar o estresse nutricional, além de técnicas convencionais como a adubação fosfatada e a calagem, observou-se que a comunidade científica tem investido em estratégias orgânicas, baseadas principalmente no reaproveitamento de resíduos. Ademais, o uso de bioestimulantes, do biochar e da biofortificação são cada vez mais usuais e promissores. Nesse contexto, recomenda-se incisivamente o fomento de pesquisas no bioma, visando diminuir as lacunas existentes

Trocas Gasosas, Crescimento e Comportamento Bioquímico em Plantas Jovens de Paricá (Schizolobium Amazonicum Huber ex Ducke) em Diferentes Concentrações de Cádmio

O objetivo deste trabalho foi avaliar os parâmetros fisiológicos, de crescimento e bioquímicos de plantas jovens da espécie (Schizolobium amazonicum Huber ex Ducke) quando submetidas em diferentes concentrações de cádmio. O experimento foi desenvolvido em casa de vegetação do Instituto de Ciências Agrárias (ICA), pertencente a Universidade Federal Rural da Amazônia (UFRA), localizado em Belém-Pará, no período de dezembro de 2017 a junho de 2018. Inicialmente foram produzidas mudas a partir de sementes de paricá oriundas da Associação das Indústrias Exportadoras de Madeira do Estado do Pará em Benevides-Pará. As sementes foram semeadas em vaso tipo Leoanard com capacidade de 4,6 L adaptados com garrafas pet contendo areia lavada e esterilizada (120 ºC por 40 min.) Decorridos 15 dias após o semeio as mesmas receberam solução nutritiva de Sarruge. Transcorridos 60 dias após o semeio foi iniciada a aplicação das concentrações de cádmio na forma de cloreto de cádmio hidratado (CdCl2.H2O). Foi utilizado o delineamento experimental inteiramente casualizado (DIC), com 5 tratamentos sendo constituídos de plantas controle (sem cádmio) e com doses de Cádmio (CdCl2 178μM, CdCl2 356 μM, CdCl2 534μM, CdCl2 712 μM) Os dados foram submetidos análise de variância pelo teste F (p < 0,05) e as diferenças entre os tratamentos analisadas pelo teste de Tukey (p<0,05) e foram ajustadas por equações de regressão polinomial P<0,01 ou 0,05 usando-se o programa Sisvar. As principais variáveis fisiológicas (fotossíntese, condutância estomática e transpiração) desestabilizaram-se em suas funções com o aumento das doses de cádmio, influenciando no processo energético das mesmas. Para as variáveis de crescimento (altura, diâmetro, número de folhas e folíolos), o cádmio proporcionou uma diminuição à medida que as doses eram aumentadas, interferindo em menor produção de biomassa foliar. As alterações dos parâmetros fisiológicos, consequentemente levaram a mudanças no metabolismo do carbono e nitrogênio dessas plantas, evidenciando baixas concentrações das variáveis que contem nitrogênio em suas estruturas como aminoácidos, prolina, glicina. O cádmio acumulou-se principalmente nas raízes, mas porém houve translocação para parte aérea. Diante disso, pode-se caracteriza-lá como fitoextratora.The aim of this work was to evaluate the physiological, growing and biochemical parameters of young plants of (Schizolobium amazonicum Huber ex Ducke) when submitted in diferente dosages of cadmium. The experimente was developed in greenhouse of Instituto de Ciências Agrárias (ICA), belonging to Universidade Federal Rural da Amazônia (UFRA), located in Belém-Pará, in a period of december 2017 to june 2018. Initially seedlings were produced from paricá seeds from Associação das Indústrias Exportadoras de Madeira do Estado do Pará in Benevides-Pará. The seeds were seeded in a Leonard type pot with a capacity of 4.6 L adapted with pet bottles containing washed and sterilized sand. After 15 days after sowing, they received nutritive solution of Sarruge (1/4 and 1/2 strength). After 60 days after sowing the application of increasing concentrations of cadmium in the form of cadmium chloride (CdCl2.H2O). Was utiized a randomized experimental design (RED), with 5 treatments being constituted of control plants (without cadmium dosages) and with cádmium dosages(CdCl2 178μM, CdCl2 356 μM, CdCl2 534μM, CdCl2 712 μM) with 7 repetitions each (one plant per pot) totalizing 35 experimental units. The obtained data were submitted to variance analysis by F test (p < 0,05) and the means were compared by the least significant difference of the Tukey's test (p<0,05) and were adjusted by polynomial regression equations P <0.01 or 0.05 using the Sisvar program. The mainly physiological variables (photosynthesis, stomatal conductance and transpiration) destabilized in their functions with the increase of the cadmium doses, influencing in the energy process of the same ones. The growth, diameter, leaf number and leaflet variables, cadmium provided a reduction as the doses were increased, interfering in the production of foliar biomass. Changes in physiological effects have consequently led to changes in plant metabolism and nitrogen, evidencing the low concentrations of nitrogen-containing molecules in their structures such as amino acids, proline, and glycine. The cadmium accumulated in the roots, but there was a translation for the aerial part. Given this, it can be corresponded as a phytoextractor

Bioquímico em Plantas Jovens de Paricá (Schizolobium Amazonicum Huber ex Ducke) em Diferentes Concentrações de Cádmio.

O objetivo deste trabalho foi avaliar os parâmetros fisiológicos, de crescimento e bioquímicos de plantas jovens da espécie (Schizolobium amazonicum Huber ex Ducke) quando submetidas em diferentes concentrações de cádmio. O experimento foi desenvolvido em casa de vegetação do Instituto de Ciências Agrárias (ICA), pertencente a Universidade Federal Rural da Amazônia (UFRA), localizado em Belém-Pará, no período de dezembro de 2017 a junho de 2018. Inicialmente foram produzidas mudas a partir de sementes de paricá oriundas da Associação das Indústrias Exportadoras de Madeira do Estado do Pará em Benevides-Pará. As sementes foram semeadas em vaso tipo Leoanard com capacidade de 4,6 L adaptados com garrafas pet contendo areia lavada e esterilizada (120 ºC por 40 min.) Decorridos 15 dias após o semeio as mesmas receberam solução nutritiva de Sarruge. Transcorridos 60 dias após o semeio foi iniciada a aplicação das concentrações de cádmio na forma de cloreto de cádmio hidratado (CdCl2.H2O). Foi utilizado o delineamento experimental inteiramente casualizado (DIC), com 5 tratamentos sendo constituídos de plantas controle (sem cádmio) e com doses de Cádmio (CdCl2 178μM, CdCl2 356 μM, CdCl2 534μM, CdCl2 712 μM) Os dados foram submetidos análise de variância pelo teste F (p < 0,05) e as diferenças entre os tratamentos analisadas pelo teste de Tukey (p<0,05) e foram ajustadas por equações de regressão polinomial P<0,01 ou 0,05 usando-se o programa Sisvar. As principais variáveis fisiológicas (fotossíntese, condutância estomática e transpiração) desestabilizaram-se em suas funções com o aumento das doses de cádmio, influenciando no processo energético das mesmas. Para as variáveis de crescimento (altura, diâmetro, número de folhas e folíolos), o cádmio proporcionou uma diminuição à medida que as doses eram aumentadas, interferindo em menor produção de biomassa foliar. As alterações dos parâmetros fisiológicos, consequentemente levaram a mudanças no metabolismo do carbono e nitrogênio dessas plantas, evidenciando baixas concentrações das variáveis que contem nitrogênio em suas estruturas como aminoácidos, prolina, glicina. O cádmio acumulou-se principalmente nas raízes, mas porém houve translocação para parte aérea. Diante disso, pode-se caracteriza-lá como fitoextratora.The aim of this work was to evaluate the physiological, growing and biochemical parameters of young plants of (Schizolobium amazonicum Huber ex Ducke) when submitted in diferente dosages of cadmium. The experimente was developed in greenhouse of Instituto de Ciências Agrárias (ICA), belonging to Universidade Federal Rural da Amazônia (UFRA), located in Belém-Pará, in a period of december 2017 to june 2018. Initially seedlings were produced from paricá seeds from Associação das Indústrias Exportadoras de Madeira do Estado do Pará in Benevides-Pará. The seeds were seeded in a Leonard type pot with a capacity of 4.6 L adapted with pet bottles containing washed and sterilized sand. After 15 days after sowing, they received nutritive solution of Sarruge (1/4 and 1/2 strength). After 60 days after sowing the application of increasing concentrations of cadmium in the form of cadmium chloride (CdCl2.H2O). Was utiized a randomized experimental design (RED), with 5 treatments being constituted of control plants (without cadmium dosages) and with cádmium dosages(CdCl2 178μM, CdCl2 356 μM, CdCl2 534μM, CdCl2 712 μM) with 7 repetitions each (one plant per pot) totalizing 35 experimental units. The obtained data were submitted to variance analysis by F test (p < 0,05) and the means were compared by the least significant difference of the Tukey's test (p<0,05) and were adjusted by polynomial regression equations P <0.01 or 0.05 using the Sisvar program. The mainly physiological variables (photosynthesis, stomatal conductance and transpiration) destabilized in their functions with the increase of the cadmium doses, influencing in the energy process of the same ones. The growth, diameter, leaf number and leaflet variables, cadmium provided a reduction as the doses were increased, interfering in the production of foliar biomass. Changes in physiological effects have consequently led to changes in plant metabolism and nitrogen, evidencing the low concentrations of nitrogen-containing molecules in their structures such as amino acids, proline, and glycine. The cadmium accumulated in the roots, but there was a translation for the aerial part. Given this, it can be corresponded as a phytoextractor

Padrão fenológico de Attalea maripa (Aubl.) Mart. em áreas de pastagens na Amazônia Oriental.

A pesquisa avaliou a fenologia de Attalea maripa (inajá), relacionando os eventos fenológicos com a precipitação pluviométrica. Os dados foram obtidos em 100 palmeiras adultas provenientes de regeneração natural, em 3,25 hectares de área de pastagens em Bonito, PA, no período de agosto de 2009 a dezembro de 2011. Os dados foram analisados por meio de fenogramas, índice de sincronia e análise fatorial. Pelo que a pesquisa evidenciou, o padrão fenológico do inajá não é sazonal. A floração e a frutificação ocorrem durante todo o ano; são eventos de longa duração, que sofrem oscilações ao longo do ano. A fenofase espata fechada é altamente sincrônica. A frutificação é um evento fenológico pouco sincrônico. A precipitação é um fator climático importante para a fenologia do inajá, pois afeta negativamente a produção de espata aberta com flores e a queda de folhas e positivamente a queda de frutos maduros.The research evaluated the Attale amaripa (inajá) phenology relating the phenological events with rainfall. Data were obtained from 100 adult palms from natural regeneration in 3.25 acres of pasture in Bonito-PA, from August 2009 to December 2011. Data were analyzed using phenograms, synchrony index and factor analysis. The research showed that the phenological pattern of inajá is not seasonal. Flowering and fruiting occur throughout the year and are long-lasting events and suffer fluctuations throughout the year. The closed spathe phenology is highly synchronous. The fruiting is a slightly synchronous phenological event. Rainfall is a major climatic factor for phenology inajá because negatively affects production of open spathe with flowers and leaves fall and positively mature fruit drop

Padrão Fenológico de Attalea maripa (Aubl.) Mart. em Áreas de Pastagens na Amazônia Oriental

RESUMO A pesquisa avaliou a fenologia de Attalea maripa (inajá), relacionando os eventos fenológicos com a precipitação pluviométrica. Os dados foram obtidos em 100 palmeiras adultas provenientes de regeneração natural, em 3,25 hectares de área de pastagens em Bonito, PA, no período de agosto de 2009 a dezembro de 2011. Os dados foram analisados por meio de fenogramas, índice de sincronia e análise fatorial. Pelo que a pesquisa evidenciou, o padrão fenológico do inajá não é sazonal. A floração e a frutificação ocorrem durante todo o ano; são eventos de longa duração, que sofrem oscilações ao longo do ano. A fenofase espata fechada é altamente sincrônica. A frutificação é um evento fenológico pouco sincrônico. A precipitação é um fator climático importante para a fenologia do inajá, pois afeta negativamente a produção de espata aberta com flores e a queda de folhas e positivamente a queda de frutos maduros

Aspectos epidemiológicos, fatores de risco e achados clinicopatológicos do melanoma em cães no Sertão, Nordeste do Brasil

Background: Melanoma is a malignant neoplasm that arises from melanocytes and malanoblasts. It is also more frequently reported in dogs than in other species. They may arise from melanocytes in the skin, on the surfaces of the mucous membranes, and eyes. The aim of this study was to describe the epidemiological aspects, risk factors and clinicopathological findings of melanoma in dogs in the backlands, northeastern Brazil. Materials, Methods &amp; Results: A retrospective study was carried out in all biopsy samples and necropsy examinations of dogs, from January 2003 to December 2021, at the Animal Pathology Laboratory of the Federal University of Campina Grande, Patos, Paraiba, northeastern Brazil. Epidemiological data, clinical signs, and gross lesions were reviewed from the diagnostic laboratory reports. Samples of the skin, lymph nodes, central nervous system and organs of the thoracic and abdominal cavities were fixed in 10% buffered formalin, processed routinely for histopathology, embedded in paraffin wax, cut into 4 µm sections, and stained with hematoxylin and eosin (HE). Histological sections were also submitted to immunohistochemistry with the primary antibody anti-Melan A. Of the 4717 records found, 1158 (24.5%) were diagnosed with neoplasms, of which 48 (4.14%) cases were of melanoma. Of this total, 28 (58.3%) dogs were elderly, 19 (39.6%) were adults, and 1 (2.1%) was young. Mixed breed animals were the most affected (42.6%), followed by the pinscher breed (19.1%). According to the anatomical region, the most affected site was the skin (38/53=71.7%), followed by the oral cavity (12/53=22.65%) and the eyes (3/53=5.7%). Grossly, the skin lesions were characterized by exophytic and usually blackened, sometimes irregular and firm, nodules. At cut, they had a smooth, compact and blackened surface. Lesions in the oral cavity were characterized by blackened, irregular and infiltrating nodules or masses. The ocular lesions were always unilateral and were characterized by an enlarged and diffusely blackened eyeball, with areas of ulceration and subversion of tissue architecture. In 5 animals there was more than one anatomical site affected, totaling 53 lesions. In 9 (17%) cases, metastases were identified, 8 in regional lymph nodes and 1 in the lung. Histopathology showed a densely non-encapsulated, poorly delimited, expansive and infiltrative neoplasm, composed of neoplastic cells arranged in islands or nests and supported by fibrovascular stroma, containing a variable amount of brownish pigment (melanin). Immunohistochemistry showed strong immunostaining of the neoplastic cells in brown by the anti-Melan A antibody. Discussion: The diagnosis of melanoma was established based on epidemiological, clinical, anatomopathological, and immunohistochemical findings. Gender is not a predisposing factor, and although there was no statistically significant relationship, males were more affected. Senescence is a conditioning risk factor. Elderly animals were more affected (P &lt; 0.0001) than adult ones, with OR = 4.38; and young ones (P = 0.0051), with OR = 12.65. Some breeds, especially those with marked skin pigmentation, were more affected, however the most affected ones in this survey were pinscher and poodle. Cutaneous melanoma accounted for almost 72% of cases, contesting recent studies where oral cavity melanoma was more frequent. Therefore, it is believed that the climatic conditions of the backlands sub-region, in northeastern Brazil, associated with the individual characteristics of the dogs, are involved in the development of these neoplasms, since the climate is predominantly dry, with high temperatures throughout the year, with maximums that can reach 40ºC, favoring the exposure to high incidence of ultraviolet radiation. Keywords: dog disease, dermatopathy, neoplasm, melanocytes. Título: Melanomas em cães no Sertão do Nordeste do Brasil - epidemiologia, fatores de risco e achados clinicopatológicos Descritores: doença de cão, dermatopatia, neoplasma, melanócitos.Background: Melanoma is a malignant neoplasm that arises from melanocytes and malanoblasts. It is also more frequently reported in dogs than in other species. They may arise from melanocytes in the skin, on the surfaces of the mucous membranes, and eyes. The aim of this study was to describe the epidemiological aspects, risk factors and clinicopathological findings of melanoma in dogs in the backlands, northeastern Brazil. Materials, Methods &amp; Results: Biopsies and necropsies performed on dogs at the Animal Pathology Laboratory of the Federal University of Campina Grande during the period from 2000 to 2021 were reviewed. Of the 4717 records found, 1158 (24.5%) were diagnosed with neoplasms, of which 48 (4.14%) cases were of melanoma. Of this total, 28 (58.3%) dogs were elderly, 19 (39.6%) were adults, and one (2.1%) was young. Mixed breed animals were the most affected (42.6%), followed by the pinscher breed (19.1%). The neoplasms were in the skin, oral cavity, and eyeball. In nine (18.75%) cases, metastases were identified, eight in lymph nodes and one in the lung. The lesions were located mainly on the skin and were characterized by a nodular and blackened growth pattern. Discussion: The diagnosis of melanoma was established based on epidemiological, clinical, anatomopathological, and immunohistochemical findings. Gender is not a predisposing factor, and although there was no statistically significant relationship, males were more affected. Senescence is a conditioning risk factor. Elderly animals were more affected (p &lt; 0.0001) than adult ones, with OR = 4.38; and young ones (p = 0.0051), with OR = 12.65. Some breeds, especially those with marked skin pigmentation, were more affected, however the most affected ones in this survey were pinscher and poodle. Cutaneous melanoma accounted for almost 72% of cases, contesting recent studies where oral cavity melanoma was more frequent. Therefore, it is believed that the climatic conditions of the Sertão sub-region, in Northeastern Brazil, associated with the individual characteristics of the dogs, are involved in the development of these neoplasms, since the climate is predominantly dry, with high temperatures throughout the year, with maximums that can reach 40ºC, favoring the exposure to high incidence of ultraviolet radiation. Keywords: Dog disease, dermatopathy, neoplasm, melanocytes