Salinity is one of the modern agriculture major obstacles, causing several physiological disturbances in plants, adversely affecting its growth and development. Therefore, some techniques are required in order to alleviate the negative effects of salinity stress on plants, as for example an adequate nitrogen fertilization. The aim of this study was to assess the ecophysiological responses of sugar apple plants (Annona squamosa L.) submitted to different salinity levels and nitrogen fertilization doses. The experimental design was a randomized block in an incomplete factorial scheme, with five electrical conductivities of the irrigation water (ECw: 0.5, 1.01, 2.25, 3.49 and 4.0 dS m-1) and five nitrogen doses (0, 101, 350, 598.2 and 700 mg dm-3), with four replicates, generated from the Box Central Composite experimental design matrix. Through a daily course, it was observed variations in gas exchange, chlorophyll content and fluorescence parameters. The gas exchange, chlorophyll content and fluorescence parameters were measured on photosynthetically active leaves. There was significant interaction between the salinity levels (ECw) and nitrogen doses for the chlorophyll indexes. The electrical conductivity of the irrigation water caused significant negative effects on chlorophyll fluorescence. Therefore, it can be stated that the sugar apple plants ecophysiology varies through the day and that salinity affects its chlorophyll content and fluorescence.

A salinidade da água de irrigação é um dos grandes entraves da agricultura moderna, podendo causar danos ao metabolismo e, consequentemente, ao desenvolvimento das plantas. Atualmente há uma grande demanda por substâncias que possam atenuar tais efeitos, dentre elas destaca-se o ácido salicílico. Com isso, objetivou-se avaliar os efeitos da aplicação de ácido salicílico na cultura da melancia (Citrullus lanatus L.) sob estresse salino. O delineamento experimental foi em blocos casualizados, em esquema fatorial incompleto, com quatro repetições e duas plantas por repetição. Os tratamentos resultaram da combinação de cinco concentrações de ácido salicílico (0,00; 0,15; 0,50; 0,85 e 1,00 mM) e cinco condutividades elétricas da água de irrigação (0,50; 1,01; 2,25; 3,49 e 4,00 dS m^-1). Aos 30 dias após transplantio foram avaliados o desenvolvimento, trocas gasosas, índices e fluorescências de clorofila. Os dados foram submetidos a análise de variância e em seguida foram produzidas bandas de confiança (confbands) e correlação de Pearson. A aplicação de ácido salicílico (até 0,85 mM) apresenta efeitos benéficos para a morfofisiologia da melancia, enquanto o aumento da condutividade elétrica da água de irrigação pode apresentar efeitos deletérios.

RESPOSTAS FISIOLÓGICAS DE MULUNGU SUBMETIDA A ESTRESSE SALINO E APLICAÇÃO DE ÁCIDO SALICÍLICO FRANCISCO ROMÁRIO ANDRADE FIGUEIREDO1; MARIA DE FÁTIMA QUEIROZ LOPES2; RONIMEIRE TORRES DA SILVA2; JACKSON SILVA NÓBREGA2; TOSHIK IARLEY DA SILVA3 E RISELANE DE LUCENA ALCÂNTARA BRUNO2 1 Departamento de Ciências Vegetais, Universidade Federal Rural do Semi-Árido - UFERSA, Rua Francisco Mota, 572, Presidente Costa e Silva, 59625-900, Mossoró - RN, Brasil. E-mail: romarioagroecologia@yahoo.com.br 2 Departamento de Fitotecnia e Ciências Ambientais, Universidade Federal da Paraíba - UFPB, Rodovia PB-079, 58397-000, Areia-PB, Brasil. E-mails: fatimaqueiroz0@gmail.com; ronimeiretorres@hotmail.com; jacksonnobrega@hotmail.com; lanebruno.bruno@gmail.com 3 Departamento de Fitotecnia, Universidade Federal de Viçosa - UFV, Avenida Peter Henry Rolfs, s/n - Campus Universitário, 36570-900, Viçosa – MG, Brasil. E-mail: iarley.toshik@gmail.com 1 RESUMO O mulungu (Erythrina velutina Willd.) é uma espécie florestal nativa da região Nordeste do Brasil, sendo utilizada para fins econômicos e medicinal. No entanto, o seu desempenho fisiológico pode ser comprometido por diversos fatores bióticos e abióticos, dentre estes, o estresse salino. Nesse sentido, a aplicação do ácido salicílico, fitohormônio de origem fenólica, torna-se uma estratégia promissora na busca de minimizar esses efeitos deletérios. Assim, o objetivou-se conhecer as respostas fisiológicas do mulungu irrigado com água salina associado a aplicação de ácido salicílico. O delineamento utilizado foi em blocos casualizados, em esquema fatorial incompleto 5x5, gerados a partir da matriz Composto Central de Box com cinco níveis de condutividade elétrica da água de irrigação (0,5; 1,74; 4,75; 7,76 e 9,0 dS m-1) e cinco doses de ácido salicílico (0,0; 0,29; 1,0; 1,71 e 2,0 mM L-1), com quatro repetições. Foram avaliadas as trocas gasosas, fluorescência e índice de clorofila aos 60 dias após a irrigação com água salina. Os dados foram submetidos à análise de variância pelo teste F, nos casos de significância foi realizada análise de regressão polinomial. A salinidade da água de irrigação ocasiona efeitos deletérios nas trocas gasosas de Erythrina velutina Willd. Os índices de clorofila foram afetados positivamente pelos níveis salinos aplicados e a fluorescência inicial das plantas foi atenuada pela aplicação de ácido salicílico. Palavras-chave: Erythrina velutina Willd, caatinga, salinidade, trocas gasosas FIGUEIREDO, F. R. A.; LOPES, M. F. Q.; SILVA, R. T.; NÓBREGA, J. S.; SILVA, T. I.; AND BRUNO, R. A. L. PHYSIOLOGICAL RESPONSES OF MULUNGU SUBMITTED TO SALT STRESS AND APPLICATION OF SALICYLIC ACID 2 ABSTRACT Mulungu (Erythrina velutina Willd.) is a forest species native to the Northeast region of Brazil, being used for economic and medicinal purposes. However, its physiological performance can be compromised by several biotic and abiotic factors, among them, saline stress. That way, the application of salicylic acid, phytohormone of phenolic origin, becomes a promising strategy in the search to minimize these deleterious effects. Thus, the objective was to learn the physiological responses of mulungu irrigated with saline water associated with the application of salicylic acid. The design was a randomized complete block, in an incomplete factorial scheme, using the Box Central Composite (CCB) matrix with five levels of electrical conductivity of irrigation water (0.5; 1.74; 4.75; 7.76 and 9.0 dS m-1), and five salicylic acid doses (0.0, 0.29, 1.0, 1.71 and 2.0 mM), with four replicates. Gas exchange, fluorescence and chlorophyll indices were evaluated 60 days after irrigation with saline water. Data were submitted to analysis of variance by the F test, in cases of significance polynomial regression analysis was performed. The salinity of irrigation water causes deleterious effects on the gas exchange of Erythrina velutina Willd. The chlorophyll indices were positively affected by saline levels applied and the initial fluorescence of the plants was attenuated by the application of salicylic acid. Keywords: Erythrina velutina Willd, caatinga, salinity, gas exchange

Sesame is considered an alternative crop for small and medium farmers in the Brazilian Northeast region. However, under the conditions of the northeastern semi-arid region, the scarcity of good quality water for irrigation may lead to a reduction in the quality of the final product. This study aimed to evaluate the physiological quality of sesame seeds produced under levels of soil salinity. The experiment was carried out in a completely randomized design, in a 5 × 5 factorial scheme, with three replicates, corresponding to sesame cultivars (BRS Seda, BRS G2, BRS G3, BRS G4 and BRS Anahi) and soil salinity levels with the following values for electrical conductivity: 0.6 dS m^-1, 1.2 dS m^-1, 1.8 dS m^-1, 2.4 dS m^-1 and 3.0 dS m^-1. The physiological quality was characterized based on tests of germination, first germination count, germination speed index, radicle length, seed electrical conductivity, emergence, emergence speed index and seedling dry matter. BRS Seda, BRS G2 and BRS G3, cultivated under salinity levels, present seeds with a better physiological quality, demonstrating a higher tolerance to salt stress conditions. The BRS Seda and BRS G2 cultivars tolerate salinity levels of up to 2.4 dS m^-1, while BRS G3 tolerates levels of up to 1.8 dS m^-1. BRS G4 and BRS Anahi have the physiological quality of their seeds compromised by the increase in the soil salinity, during their production.

Basil is a medicinal and spice plant widely used in the Northeast region of Brazil. However, its production can be affected by the soil salinity and water used for irrigation. For the development of plants in saline conditions to occur, it is necessary that their nutritional status is adequate. Thus, the objective was to evaluate the effect of nitrogen fertilization on growth and gas exchange of purple basil submitted to salinity. The experiment was performed at the Federal University of Paraíba, adopting a randomized block design in an incomplete 5 x 5 factorial scheme, with five electrical conductivities (ECw = 0.0, 0.81, 2.75, 4.69 and 5.50 dS m⁻¹) and five doses of nitrogen (N = 0.00, 58.58, 200.00, 341.42 and 400.00 mg L⁻¹), generated through the central composite design. Plant height, number of leaves, stem diameter, leaf area and root length were evaluated at 45 days. Stomatal conductance, net CO₂ assimilation rate, transpiration, water use efficiency, intrinsic water use efficiency, intrinsic efficiency of carboxylation and leaf temperature were evaluated. The data were analyzed through analysis of variance and regression. Foliar N fertilization attenuated the harmful effect of salt stress, increasing stem diameter, net CO₂ assimilation rate, intrinsic efficiency of carboxylation and leaf temperature. Salinity reduced the growth of basil plants as the ECw rised. Gas exchange was stimulated by salinity and reduced by the foliar N fertilization. The number of leaves and leaf area increased with nitrogen fertilization.