ABSTRACT: Microbial biodiversity of an environment can contribute to plant growth and increase crop yield. Plant extracts from soybean (Glycine max (L.) Merrill) were investigated on soybean plants grown after inoculation with these extracts. Soil samples were collected from two important Brazilian soybean-growing regions to produce the extracts used in the experiments. The extracts were produced with material collected from aboveground biomass and rhizosphere of soybean plants cultivated in a controlled greenhouse (phase 1). The extracts produced in phase 1 were applied in a sequential experiment (phase 2). Phase 2 was conducted to examine the plant microbiome after the microbial alteration process in the greenhouse through seed inoculation with the extracts produced previously. Samples of aboveground biomass were collected to determine root dry matter and crop yield. Bacterial 16S rRNA sequences were processed to determine the final microbial content of soybean. The inoculated treatments had lower species diversity; however, the phyla Firmicutes and Bacteroidetes were more abundant in the treatments than in the non-inoculated treatment. The soybean plant stem in the inoculated treatment also had a positive response to enrichment of the bacterial classes Betaproteobacteria, Bacilli and Flavobacteria. Inoculation affected the microbial composition of soybean plants. The alteration of microbiome changes revealed differences for crop yield between the inoculated and non-inoculated treatments, with up to 93.5 % higher crop yields per plant according to the extract applied.

ABSTRACT Objective: to determine risk factors for suicidal behavior among students and employees of a federal public university in the Brazilian Western Amazon. Methods: an analytical cross-sectional study of survey and association between variables with a sample of 475 participants. Statistical analyzes were performed using the Mann-Whitney test, Pearson’s chi-square test, likelihood ratio test or Fisher’s exact test and a logistic regression model. A significance level of 5% was used (p-value< 0.05). Results: a higher proportion of suicidal behavior was found in younger participants, females, who had no religion or had one, but were non-practicing, who did not have children and/or had a monthly family income of less than two minimum wages. Lower proportions of suicidal behavior were identified in heterosexuals and/or married or in a stable relationship. Conclusion: the study suggests a relationship between sociodemographic factors and suicidal behavior in the studied academic community.

RESUMEN Objetivo: determinar los factores de riesgo para la conducta suicida entre estudiantes y empleados de una universidad pública federal en la Amazonía occidental brasileña. Métodos: estudio analítico transversal de encuesta y asociación entre variables con una muestra de 475 participantes. Los análisis estadísticos se realizaron mediante las pruebas Mann-Whitney, chi-cuadrado de Pearson, razón de verosimilitud o exacta de Fisher y un modelo de regresión logística. Se utilizó un nivel de significancia del 5% (p-valor <0,05). Resultados: se encontró mayor proporción de conducta suicida en los participantes más jóvenes, mujeres, que no tenían religión o la tenían pero no la practicaban, que no tenían hijos y/o tenían un ingreso familiar mensual inferior a dos salarios mínimos. Se identificaron menores proporciones de conducta suicida en heterosexuales y/o casados o en relación estable. Conclusión: el estudio sugiere una relación entre factores sociodemográficos y conducta suicida en la comunidad académica estudiada.

RESUMO Objetivo: determinar os fatores de risco para o comportamento suicida entre estudantes e servidores de uma universidade pública federal da Amazônia Ocidental brasileira. Métodos: estudo do tipo transversal analítico de levantamento e associação entre variáveis com uma amostra de 475 participantes. As análises estatísticas foram feitas por Teste de Mann-Whitney, Teste Qui-Quadrado de Pearson, Teste da Razão de Verossimilhança ou Teste Exato de Fisher e modelo de regressão logística. Foi utilizado um nível de significância de 5% (p-valor < 0,05). Resultados: foi encontrada maior proporção de comportamento suicida em participante com idade menor, sexo feminino, que não possuía religião ou possuía, mas não era praticante, que não tinha filhos e/ou possuía renda familiar mensal inferior a dois salários mínimos. Menores proporções de comportamento suicida foram identificadas em heterossexuais e/ou casados ou em união estável. Conclusão: o estudo sugere relação entre fatores sociodemográficos com o comportamento suicida na comunidade acadêmica estudada.

RESUMO A presença de águas com elevados concentrações de sais se destaca como fator limitante da qualidade da produção agrícola. Assim, objetivou-se com este estudo avaliar a qualidade de frutos da aceroleira cv. Flor Branca, submetida à irrigação com diferentes níveis de águas salinas e combinações de adubação com nitrogênio-potássio, entre 630 e 750 dias após o transplantio a campo. Utilizou-se delineamento de blocos ao acaso em arranjo fatorial 5 × 4, com três repetições, cujos tratamentos foram cinco condutividades elétricas da água - CEa (0,3; 1,3; 2,3; 3,3 e 4,3 dS m-1) e quatro combinações de adubação com nitrogênio e potássio: 70-50; 100-75; 130-100 e 160-125% da recomendação de N e K2O, respectivamente. A CEa acima de 0,3 dS m-1 diminuiu o diâmetro polar e equatorial, potencial hidrogeniônico, teores de flavonoides e aumentou a acidez titulável nos frutos de aceroleira. A combinação de 70-50% da recomendação de N e K2O, diminuiu o efeito do estresse salino da água de irrigação sobre o teor de antocianina nos frutos na CEa de 1,3 dS m-1, e ácido ascórbico, nas salinidades de 3,3 e 4,3 dS m-1.

ABSTRACT The presence of waters with high salt concentration stands out as a limiting factor for the quality of agricultural production. Thus, this study aimed to evaluate the fruit quality of West Indian cherry cv. Flor Branca, subjected to irrigation with water of different salinity levels and combinations of nitrogen-potassium fertilization, between 630 and 750 days after transplanting in the field. A randomized block design was used in a 5 × 4 factorial arrangement, with three replicates, whose treatments consisted of five values of electrical conductivies of irrigation water - ECw (0.3, 1.3, 2.3, 3.3 and 4.3 dS m-1) and four combinations of nitrogen and potassium fertilization (70-50, 100-75, 130-100 and 160-125% of recommendation of N and K2O, respectively). Electrical conductivity of irrigation water above 0.3 dS m-1 reduces the polar and equatorial diameters, hydrogen potential and flavonoid concentration and increases titratable acidity in West Indian cherry fruits. N-K2O combination of 70/50% of fertilizer recommendation reduces the effect of salt stress of irrigation water on the anthocyanin concentration in the fruits at ECw of 1.3 dS m-1 and ascorbic acid at ECw of 3.3 and 4.3 dS m-1.

A previous study for the identification of acetylcholinesterase (AChE) inhibitors demonstrated that the hybrid between tyrosol, the 1,2,3-triazole nucleus, and the coumarin group, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (10), has a high enzyme inhibitory activity. Here, we synthesized analogues of 10 via triazole with pharmacophoric groups represented by tyrosine, phenylalanine, tryptophan, and glycine in addition to evaluating the impact of coumarin-linked amino acids on AChE inhibition. We obtained eight triazoles, six of which are undescribed. In general, the presence of carboxylic acid decreased the inhibitory activity, while aromatic amino acids increased enzymatic inhibition compared to glycine. The derivative containing tyrosine, structurally most similar to 10, presented the lowest inhibition percentage, indicating that phenolic hydroxyl is not the preponderant factor for inhibition. Molecular docking was not enough to explain in vitro experiments. On the other hand, MlogP (logP calculated by the Moriguchi method) was related positively to enzymatic inhibition. To increase the hydrophobicity of the molecules, we tested the esterified triazole derivatives comparatively with the enzyme. The compound ethyl 2-(4-(((4-methyl-2-oxo-2H-chromen-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)acetate (6) presented an increment of inhibitory activity of 46.97 ± 1.75% at 100 μmol L-1. We also associated the best activity with the lowest van der Waals volume and molar mass values.

Resumo O objetivo do trabalho foi avaliar a influência de combinações de doses de nitrogênio e potássio sobre a fisiologia e a produção de frutos de aceroleira irrigada com água de diferentes salinidades, no segundo ano de cultivo. O experimento foi conduzido no município de Pombal-PB, Brasil, em recipientes plásticos adaptados como lisímetros instalados em campo, em delineamento de blocos ao acaso, esquema fatorial 5 x 4 referentes a cinco níveis de condutividades elétricas da água de irrigação (CEa): 0,3; 1,3; 2,3; 3,3 e 4,3 dS m-1 e quatro combinações de adubação nitrogenada e potássica: 70% N + 50% K2O; 100% N + 75% K2O; 130% N + 100% K2O e 160% N + 125% K2O da dose recomendada para aceroleira, com três repetições e uma planta por parcela. Estudou-se a cv. Flor Branca enxertada sobre a cv. Junco, entre 420 e 550 dias após o transplantio. As combinações de nitrogênio e potássio não mitigam os efeitos deletérios da salinidade da água sobre a fisiologia e a produção de frutos da aceroleira. O aumento na CEa intensifica os danos às membranas celulares, reduz o potencial hídrico no ramo, teor de clorofila nas folhas, taxa de assimilação de CO2, diâmetro equatorial e polar e a massa de frutos. A adubação das plantas com 70% de N + 50% de K2O, em relação às outras combinações de adubação, causa menor extravasamento de eletrólitos e proporciona maior taxa de assimilação de CO2, teor de clorofila nas folhas, frutos de maior tamanho e massa.

Abstract This study evaluated the influence of combinations of nitrogen and potassium doses on the physiology and fruit production of West Indian cherry irrigated with waters of different salinities in the second year of cultivation. The experiment was conducted in the municipality of Pombal-PB, Brazil, in plastic containers adapted as lysimeters installed in the field, in a randomized block design, 5 x 4 factorial scheme corresponding to five levels of electrical conductivity of irrigation water (ECw): 0.3, 1.3, 2.3, 3.3 and 4.3 dS m-1, and four combinations of nitrogen and potassium fertilization: 70% N + 50% K2O; 100% N + 75% K2O; 130% N + 100% K2O and 160% N + 125% K2O of the dose recommended for West Indian cherry, with three replicates and one plant per plot. The cv. ‘Flor Branca’ was grafted on the cv. ‘Junco’, between 420 and 550 days after transplanting. Nitrogen and potassium combinations did not mitigate the deleterious effects of water salinity on the physiology and fruit formation of West Indian cherry. An increase in ECw intensifies the intercellular electrolyte leakage and reduces the water potential in the branch, chlorophyll content in the leaves, CO2 assimilation rate, equatorial and polar diameters as well as the mass of fruits. Fertilization of plants with 70% N + 50% of K2O, compared to the other fertilization combinations, causes less intercellular electrolyte leakage and promotes higher CO2 assimilation rates, higher chlorophyll content in leaves, and fruits of larger size and mass.

Carpotroche brasiliensis is a tree native to Brazil, belonging to the family Flacurtiaceae, whose seeds contain a group of cyclopentenyl fatty acids: gorlic (12%), chaulmugric (27%), and hydnocarpic (48.7%). These compounds are considered the main therapeutic agents in the treatment of leprosy. In the present study, a series of novel triazole compounds were obtained by conjugation between hydnocarpic acid and functionalized azides via copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC). Hydnocarpic acid and its derivatives were tested against estrogen-positive breast carcinoma (MCF-7), hepatocellular carcinoma (HepG2), and non-small cell lung cancer (A549) cell lines. The (R)-(1-(pyridin-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl-11-(cyclopent-2-en-1-yl)undecanoate (8) displayed promising antiproliferative activity against A549 cells. We demonstrated that this compound selectively inhibited the viability of A549 cell cultures. Furthermore, compound 8 inhibited the clonogenic capacity of A549 cells, and this effect was associated to its ability to inhibit cell cycle progression at G1 phase. These findings indicate that 8 is a promising antitumor agent on A549 cells and support further studies to evaluate the molecular mechanisms underlying its antiproliferative activity. In addition, hydnocarpic acid should be considered as a promising chemical prototype to obtain novel antineoplastic agents.

Nematode is a major problem in agriculture, the effective way to control this pest is through chemical control, but the efficient molecules present in the market have great toxicity to mammals and birds. Thus, there is a constant demand for the development of new nematicide molecules. This study describes the synthesis of 21 novel esters derived from norbornadiene and evaluation of their potential activity against Meloidogyne javanica. The esters 5-25 presented 50% mortality of the nematodes. The acid 3 and the ester 4 caused 96 and 93% mortality of the nematodes, respectively. The lethal concentration to kill 50% of the nematodes (LD50) were determined as being 11.8 µg mL-1 for the acid 3 and 99.4 µg mL-1 for the ester 4. According to the results obtained it is believed that polarity seems to be a key factor for the higher activity of compound 3 compared to structurally similar ester derivatives.

Abstract This study aimed to isolate lactic acid bacteria from sheep milk products and to characterize these microorganisms with a focus on their antimicrobial, proteolytic and lipolytic activities. Raw milk, pasteurized milk, pasteurized cream, and butter samples were collected, lactic acid bacteria were isolated and their proteolytic, lipolytic and antimicrobial activities were evaluated. Lactic acid bacteria counts were higher in raw milk collected at the farm number 4 (8.91 ± 0.05 log CFU/mL), in which adequate hygienic practices were observed for pre- and post-milking. A total of 253 isolates were obtained, and among them 37 were lactic acid bacteria, where 19 showed some type of activity, most of which from raw milk. Among the isolates of lactic acid bacteria, 48.65% (n=18) showed proteolytic activity, 13.51% (n=5) lipolytic activity, 10.81% (n=4) showed both proteolytic and lipolytic activities, and only 2.70% (n=1) showed antimicrobial activity. Isolation of lactic acid bacteria with technological properties demonstrated their potential use as starter cultures in processing of fermented dairy products.

Resumo: O objetivo deste trabalho foi avaliar o uso da altura do dossel da planta como variável de ajuste para melhorar as medições indiretas do índice de área foliar (IAF). Três experimentos foram conduzidos com diferentes culturas - milho (Zea mays), soja (Glycine max) e cana-de-açúcar (Saccharum officinarum) -, para comparar o desempenho do IAF medido indiretamente (IAFind) e corrigido pela variável de ajuste com o IAF medido diretamente (IAFref). Sem a correção proposta, o IAFind tendeu a ser superestimado em 20%, em média, em relação ao IAFref, para as três culturas. Após o uso da altura da colheita para ajustar o IAFind, observaram-se fortes relações positivas entre o IAFref e o IAFind corrigido (R2 = 0,96); a superestimação foi reduzida para 4% e o erro médio quadrático diminuiu para 0,35 m2 m-2. A variável altura do dossel mostra-se promissora para correção do IAF das culturas de soja, milho e cana-de-açúcar.

Abstract: The objective of this work was to evaluate the use of plant height as a calibration variable for improving indirect measurements of the leaf area index (LAI). Three experiments were conducted with different crops - corn (Zea mays), soybean (Glycine max), and sugarcane (Saccharum officinarum) -, to compare the performance of the LAI measured indirectly (LAIind) and corrected by the calibration variable with the LAI measured directly (LAIref). Without the proposed correction, the LAIind tended to be overestimated by 20%, on average, compared with the LAIref, for the three crops. After crop height was used to adjust the LAIind, a strong positive relationship was observed between the LAIref and the corrected LAIind (R2 = 0.96); overestimation was reduced to 4% and the root-mean-square error decreased to 0.35 m2 m-2. The variable canopy height is promising for the correction of the LAI of the soybean, corn, and sugarcane crops.

RESUMO O manejo da adubação tem sido uma das tecnologias estudadas no propósito de diminuir o desequilíbrio nutricional nas plantas submetidas ao estresse salino. Neste sentido, objetivou-se com a pesquisa, analisar o efeito da combinação de adubação nitrogenada e potássica sobre a morfologia e produção da aceroleira irrigada com águas salinas no primeiro ano de cultivo. O experimento foi conduzido no CCTA/UFCG, em lisímetros de 60 L instalados em campo, em delineamento de blocos ao acaso e esquema fatorial 5 x 4, referentes a cinco níveis de salinidade da água de irrigação (CEa): 0,3; 1,3; 2,3; 3,3 e 4,3 dS m-1 e quatro combinações (C) de adubação nitrogenada-potássica: C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3 = 130% N + 100% K2O e C4 = 160% N + 125% K2O da dose recomendada para aceroleira, com três repetições e uma planta por parcela constituída de um lisímetro. Estudou-se a cv. Flor Branca enxertada sobre porta-enxerto da cv. Junco. A combinação de adubação com 70% N + 50% K2O promoveu maiores valores das variáveis morfológicas e de produção e, mitigou o efeito da salinidade sobre diâmetro de fruto até a CEa de 1,3 dS m-1. A adubação nitrogenada-potássica a partir da combinação de 130% N + 100% K2O prejudicaram a morfologia e a produção das plantas. A CEa acima de 0,3 dS m-1 diminuiu o diâmetro de caule, o tamanho e peso médio de frutos da aceroleira no primeiro ano de cultivo.

ABSTRACT Fertilization management is one of the technologies studied to reduce nutritional imbalance in plants submitted to saline stress. In this context, we analyzed the effect of the combination of nitrogen and potassium fertilization on the morphology and production of West Indian cherry irrigated with saline waters in the first year of cultivation. The experiment was carried out in the CCTA/UFCG, in 60-L lysimeters installed in the field, in a randomized block design and 5 x 4 factorial scheme, referring to five levels of irrigation water salinity (ECw), i.e., 0.3, 1.3, 2.3, 3.3, and 4.3 dS m-1, and four combinations (C) of nitrogen-potassium fertilization, i.e., C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3 = 130% N + 100% K2O, and C4 = 160% N + 125% K2O of the recommended dose for West Indian cherry, with three replicates and one plant per plot consisting of a lysimeter. The cv. ‘Flor Branca’, grafted on cv. Junco, was studied. The combination of fertilization with 70% N + 50% K2O promoted higher morphology and production values and mitigated the effect of salinity on fruit diameter up to an ECw of 1.3 dS m-1. Nitrogen-potassium fertilization in the combination of 130% N + 100% K2O impaired plant morphology and production. The ECw above 0.3 dS m-1 decreased the stem diameter, size, and average weight of fruits of West Indian cherry in the first year of cultivation.

ABSTRACT Maize (Zea mays) is considered one of the most important crops for world food security. Globally, Brazil is the second largest maize producer and the fourth largest maize consumer. The climate variables is one of the main determining factors for crop yield. Given the possibility of future climate changes, our objective was to evaluate the impact of climate change on maize crop growth and development, assessed strategies to cope with the future crop andto quantify the impacts on various producing regions of Brazil. The DSSAT/CERES-Maize model was calibrated with field data and then used to simulate current and six future climate scenarios, according to the AgMIP protocols. We selected three regional climate circulation models (GCMs) and two representative concentration pathways (RCPs) for the period of 2040-2069. For most of the producing regions, the simulations showed a decreasing trend during both the summer and autumn sowing seasons, except the autumn crops in Southern Brazil. We found the air temperature rise as the main factor for yield decreasing, and this finding provides an adaptation option to cope with future climate, as the country has a great latitudinal range for crop management, meaning genotypes with extended cycles could compensate the climate change, and thereby avoid the yield loss for maize crops.

Propôs-se com a presente pesquisa avaliar o efeito de diferentes combinações de doses de nitrogênio e potássio sobre o crescimento e a fisiologia da cultura da aceroleira irrigada com águas salinas. O experimento foi realizado em campo, no CCTA/UFCG, em delineamento de blocos ao acaso, e tratamentos dispostos em esquema fatorial 5 x 4, referentes a cinco salinidades da água de irrigação (CEa) de 0,3; 1,3; 2,3; 3,3 e 4,3 dS m-1 e quatro combinações (C) de doses recomendadas de nitrogênio e potássio, sendo C1 = 70%N + 50%K2O; C2 = 100%N + 75%K2O; C3= 130%N + 100%K2O e C4= 160%N + 125%K2O, com três repetições, uma planta por parcela, totalizando 60 parcelas sem bordadura. A combinação das doses de 70%N (35 g de N) + 50% K2O (20 g de K2O por planta) foi mais efetiva no aumento das trocas gasosas, promovendo maior crescimento de plantas. A maioria das variáveis de crescimento e as fisiológicas não foram comprometidas pela irrigação com salinidade da água de até 4,3 dS m-1 e, não houve mitigação do estresse salino pela combinações das doses de adubação nitrogenada e potássica.

This research aimed to evaluate the effect of different combinations of nitrogen and potassium doses on the growth and physiology of the crop of the West Indian cherry irrigated with saline waters. The experiment was carried out in the field at the CCTA/UFCG, in a randomized block design, with treatments arranged in a 5 x 4 factorial scheme, referring to five irrigation water salinities (ECw) of 0.3, 1.3, 2.3, 3.3 and 4.3 dS m-1 and four combinations (C) of doses of nitrogen (N) and potassium (K2O), with C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3 = 130% N + 100% K2O and C4 = 160% N + 125% K2O, with three replications, one plant per plot, totaling 60 plots without border. Most of the growth and physiological variables were not compromised by irrigation with water salinity up to 4.3 dS m-1 and, there was no salt stress mitigation by combinations of doses of nitrogen and potassium fertilization. The combination of the doses of 70% N (35 g of N) + 50% K2O (20 g of K2O per plant) was more effective in increasing the gas exchange, promoting greater plant growth.

Objetivou-se com este trabalho avaliar os efeitos de distintas salinidades da água de irrigação sobre o crescimento de porta-enxertos de goiabeira cv. Paluma adubada com doses crescentes de potássio, em experimento conduzido sob condições de estufa do CCTA/UFCG município de Pombal - PB. O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial 5 x 4, cujos tratamentos resultaram da combinação de cinco níveis de condutividade elétrica da água de irrigação (CEa = 0,3; 1,1; 1,9; 2,7 e 3,5 dS m-1) e quatro doses de potássio (70, 100, 130 e 160% de K) sendo a dose referente a 100% de K correspondente a 726 mg de K dm-3 de substrato, com quatro repetições e duas plantas por parcela, sem bordadura. O aumento da salinidade da água de irrigação reduz o crescimento de porta-enxerto de goiabeira cv. Paluma, sendo os efeitos mais deletérios em níveis superiores a 1,9 dS m-1; doses crescentes de K até 1.161,6 mg de K dm-3 de substrato não atenuaram os efeitos nocivos dos sais, bem como, não exerceram diferença sobre o crescimento da maioria das variáveis de porta-enxerto de goiabeira cv. Paluma aos 120 e 225 dias após a emergência.

The objective of this work was to evaluate the effects of different irrigation water salinities on the growth of guava rootstock cv. Paluma fertilized with increasing doses of potassium, in an experiment conducted under greenhouse conditions of the CCTA / UFCG municipality of Pombal - PB. The experimental design was a randomized complete block design in a 5 x 4 factorial scheme, whose treatments resulted from the combination of five levels of electrical conductivity of the irrigation water (ECw = 0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1) and four doses of potassium (70, 100, 130 and 160% K), the dose corresponding to 100% K corresponding to 726 mg K dm-3 substrate, with four replicates and two plants per plot, no border. The increase of salinity of the irrigation water reduces the growth of guava rootstock cv. Paluma, the most deleterious effects being at levels above 1.9 dS m-1; increasing doses of K up to 1161.6 mg K dm-3 substrate did not attenuate the harmful effects of the salts, nor did they exert any difference on the growth of most of the variables of guava rootstock cv. Paluma at 120 and 225 days after the emergency.

RESUMO A adubação nitrogenada vem sendo testada na mitigação do estresse salino, em algumas espécies inclusive em frutíferas; todavia, atenção especial deve ser dada à fonte de N devido às diferentes composições e os índices salinos dos fertilizantes, principalmente quando se irriga com águas de salinidade restritiva à agricultura. Neste sentido, estudou-se o efeito da adubação com fontes de nitrogênio sobre o crescimento e trocas gasosas de gravioleira irrigada com águas salinas após o transplantio. O experimento foi desenvolvido em casa de vegetação do Centro de Tecnologia e Recursos Naturais da Universidade Federal de Campina Grande, com os tratamentos distribuídos em blocos casualizados, em esquema fatorial 4 x 4, correspondente aos níveis de condutividade elétrica da água de 0,5; 1,1; 2,5 e 3,5 dS m-1 e as fontes de nitrogênio: ureia, sulfato de amônia, nitrato de cálcio e nitrato de potássio, com três repetições. O crescimento e as trocas gasosas da gravioleira aos 110 dias após o transplantio não foram influenciados pela interação entre a salinidade da água e as fontes de nitrogênio e nem pela ação isolada de N, mas foram inibidos pelo aumento da salinidade da água a partir de 0,5 dS m-1. O aumento da salinidade da água inibiu a abertura estomática e a carboxilação no interior das folhas.

ABSTRACT Nitrogen (N) fertilization has been tested for the mitigation of salt stress in some species including fruit crops. However, special attention should be paid to the source of N, due to the different compositions and saline indices of the fertilizers, particularly when irrigation is conducted using waters with salinity levels that are restrictive to agriculture. Thus, this study evaluated the effect of fertilization with N sources on the growth and gas exchanges of soursop irrigated with saline water after transplanting. The experiment was carried out in greenhouse at the Center of Technology and Natural Resources of the Federal University of Campina Grande, and treatments were arranged in randomized blocks, in 4 x 4 factorial scheme, corresponding to electrical conductivity of water - 0.5, 1.1, 2.5 and 3.5 dS m-1, and the N sources urea, ammonia sulfate, calcium nitrate and potassium nitrate, with three replicates. Growth and gas exchanges of soursop at 110 days after transplanting were not influenced by either the interaction between water salinity and N sources or the individual action of N, but were inhibited by the increase in water salinity from 0.5 dS m-1. Increasing water salinity inhibited stomatal opening and carboxylation in the leaves.