Cowpea is widely cultivated in semiarid regions; however, these regions face serious problems with salinity of water and soil, thus constituting an abiotic stress that limits the development of this species. The objective of this study was to study the influence of phosphate fertilization on the morphophysiological components of cowpea plants irrigated with salinized water during the vegetative and reproductive phase. The research was carried out in a greenhouse from September to December 2015. A randomized complete block design with treatments arranged in a 5 x 3 factorial scheme with five replications was used. The factors consisted of the use of five levels of electrical conductivity of irrigation water: 0.5; 1.5; 2.5; 3.5 and 4.5 dS m-1 and three doses of phosphorus corresponding to 60%, 100% and 140% of the dose recommended for the culture that was 60 kg ha-1. The plants of cowpea cv. Paulistinha were cultivated in lysimeters with a capacity of 8 dm3. At 30 and 49 days after sowing, periods corresponding to the vegetative (V4) and reproductive (V8 / R1) phases of the culture were evaluated gas exchange, chlorophyll fluorescence and growth. The increase in the electrical conductivity of the water reduced the growth, the photochemical activity and the phytomass accumulation of the cowpea plants, independent of the phenological phase. The higher dose of simple superphosphate increased the growth and photosynthetic activity of cowpea, mainly in the reproductive phase; Independent of the salinity of irrigation water.

RESUMO: A elevada taxa de evaporação e a limitação de água, em quantidade e qualidade principalmente nas áreas áridas e semiáridas, requerem a busca de estratégias que viabilizem a atividade agrícola. Com este trabalho objetivou-se avaliar a salinidade da água, o revestimento da cova e cálcio na produção e qualidade de maracujazeiro amarelo 'BRS Gigante Amarelo'. O experimento foi desenvolvido no município de Remígio-PB. Os tratamentos foram organizados em parcela subdividida 2A x (2R x 5Ca), correspondente a salinidade da água (0,3 e 4,0 dS m-1), sem e com proteção lateral das covas e doses de cálcio (0, 30, 60, 90 e 120 kg ha-1). A água salina reduziuo número de frutos por planta e produtividade,com maior intensidade com o uso de revestimento lateral das covas, dependendo da dose de cálcio aplicada. O aumento de cálcio reduziu a acidez titulável (AT) da polpa dos frutos das plantas irrigadas com água não salina. Os sólidos solúveis (SS) aumentaram em função do revestimento das covas. A relação SS/AT e os açúcares não redutores não foram afetados pelas fontes de variação. A aplicação de cálcio aumentou a produção, o rendimento em polpa e diminuiu a acidez dos frutos.

The objective of this study was to evaluate the interaction between water salinity and doses of nitrogen and phosphorus on chlorophyll a fluorescence and on the growth of West Indian Cherry (‘acerola’) plants in the initial growth stage. The research was carried out in a protected environment, in lysimeters filled with Regolithic Neosol of loamy clay texture and low initial phosphorus content. The experiment was conducted in a randomized block design, arranged in a factorial scheme with two factors, five levels of electrical conductivity of the irrigation water - ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four proportions of the recommendation of phosphorus/nitrogen - P/N (100:100, 140:100, 100:140 and 140:140% P/N of recommendation), with three replicates, and each plot consisted of one plant. Water salinity above 2.2 dS m-1 decreases the quantum efficiency of photosystem II and the growth of west indian cherry plants. Increase in nitrogen and/or phosphorus supply improves the energy stability of west indian cherry plants by reducing the effects of salt stress on the quantum efficiency of photosystem II. The increase of 40% in the nitrogen dose increased the chlorophyll a fluorescence, but did not influence the plant growth.

This study aimed to evaluate the interaction between the fertilization with nitrogen (N) and phosphorus (P) and irrigation with saline water on the water relations, gas exchanges and chlorophyll a fluorescence in West Indian cherry in the vegetative stage. The study was carried out in protected environment, using lysimeters filled with clay loam Regolithic Neosol, with low P content, installed in a randomized block design, arranged in a factorial scheme with five levels of electrical conductivity of irrigation water (ECw), and four managements of P and N fertilization, with three replicates and one plant per plot. Along the experiment, water relations, gas exchanges and chlorophyll a fluorescence were evaluated in West Indian cherry plants. The increase in irrigation water salinity reduces the gas exchanges of the plants, but the increment of 40% in N supply increases the photosynthetic activity of West Indian cherry at recommendation levels higher than 100:100% of the P/N ratio, when irrigated with ECw of up to 3.0 dS m

ABSTRACT. This study evaluated the effects of different light regimes and temperatures on the germination of S. hispanica seeds and used a factorial scheme in a completely randomized experimental design, in which three light conditions were combined with six temperatures (constant 20, 25, 30 and 35°C and alternating 20-30 and 25-30°C), totaling 18 treatments with four 50-seed replications. The seeds were sown on blotting paper in transparent plastic boxes and then allowed to germinate in Biochemical Oxygen Demand germinators. The seeds were evaluated over a period of eight days with respect to the following variables: germination percentage, average germination time, shoot and root lengths, shoot and root dry weights and root-shoot ratio. The data were submitted to Tukey's test (p ≤ 0.05%). The S. hispanica seed (beige colored) germination test can be carried out at constant (25°C) or alternating (25-30°C) temperatures. The germination of the seeds was indifferent to the light conditions evaluated; however, there was increased seedling growth and dry matter accumulation in the presence of light. The duration of the S. hispanica seed germination test can be five days, with the first count on the second day after sowing.Keywords: chia, seeds analysis, germination test.Regime de luz e temperatura na germinação de sementes de Salvia hispanica L. RESUMO.A pesquisa teve como objetivo avaliar os efeitos de diferentes regimes de luz e temperaturas sob a germinação de sementes de S. hispanica. Adotou-se delineamento experimental inteiramente casualizado em esquema fatorial constituído pela combinação de três condições de luminosidade (luz constante, escuro constante e alternância luz/escuro com 8h de luz e 16h de escuro) e seis temperaturas (quatro temperaturas constantes 20, 25, 30 e 35°C, e duas alternadas 20-30 e 25-30°C), perfazendo 18 tratamentos em quatro repetições de 50 sementes. As sementes foram semeadas em caixas plásticas transparentes, tendo como substrato papel mata-borrão e colocadas para germinar em Biochemical Oxigen Demand. As sementes foram avaliadas durante oito dias através das seguintes variáveis: percentagem de germinação, tempo médio de germinação, comprimento da parte aérea e da radícula, massa seca da parte aérea e da radícula e relação raiz/parte aérea. Os dados foram submetidos ao teste de Tukey (p ≤ 0,05%). O teste de germinação de sementes de S. hispanica (coloração bege) pode ser conduzido em temperaturas constante de 25°C e alternada de 25-30°C. A germinação das sementes mostrou-se indiferente à luminosidade, no entanto, verificou-se maior crescimento das plântulas e acúmulo de massa seca na presença de luz. A duração do teste de germinação de sementes S. hispanica pode ser de cinco dias, com a primeira contagem realizada no segundo dia após a semeadura.Palavras-chave: chia, análise de sementes, teste de germinação.

The quantitative and qualitative scarcity of water resources is a frequent problem in the semi-arid region of the Brazilian Northeast. The availability of water for irrigation with high content of dissolved salts is common, affecting the growth and development of the crops. Thus, it is necessary to adopt strategies that allow the establishment of irrigated agriculture in this region. The objective of this study was to evaluate the effect of water salinity and phosphorus/nitrogen combinations on the ecophysiology of the West Indian cherry grafted in the first year of cultivation. The research was carried out in a protected environment, in lysimeters filled with a Regolithic Neosol of loamy clay texture, having low initial phosphorus content. The experiment was arranged in a randomized block design, arranged in a 5x4 factorial scheme, with five levels of electrical conductivity of the irrigation water-ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four managements of fertilization with phosphorus and nitrogen (100:100; 140:100; 100:140 and 140:140% P/N of the recommendation), with three replications, each plot consisting of one plant. Increased salinity of irrigation water reduced growth, photosynthesis and the production of West Indian cherry. Fertilization with 140% of recommendation of the phosphorus and nitrogen minimizes the deleterious effect of salinity on West Indian cherry irrigated with water up to 3.0 dS m-1 .

This study aimed to evaluate the effect of physiological priming with salicylic acid on the mitigation of water and salt stresses on onion (Allium cepa L.) seeds. For this, seeds of onion, cultivar IPA 11, were soaked in salicylic acid solution (50 µM) for 24 h and placed to germinate at different water and saline potentials. For water stress, the experiment was conducted in a completely randomized design, in a 2 x 5 factorial scheme (salicylic acid with 0 and 50 µM and osmotic potentials of 0, -0.1, -0.2, -0.3, -0.4 MPa induced by polyethylene glycol 6000), with four repetitions of 50 seeds per plot. In salt stress, the adopted experimental design was completely randomized, with treatments distributed in a 2 x 4 factorial scheme (salicylic acid at concentrations of 0 and 50 µM and the osmotic potentials of 0, -0.3, -0.6 and -0.9 MPa induced by NaCl), in four repetitions of 50 seeds. For both experiments, germination, growth and accumulation of organic solutes were evaluated. Salicylic acid did not stimulate the germination of onion seeds in the absence of stress, but the application of 50 µM of salicylic acid increased the germination speed, growth and dry matter accumulation under conditions of water and salt stress. Onion plants were efficient in performing osmotic adjustment up to the potentials of -0.2 MPa induced by PEG 6000 under water stress and of -0.4 MPa induced by NaCl under salt stress.

This work aimed to study the effect of chemical and organic conditioners on the chemical attributes of a saline-sodic soil and on the initial growth of two castor bean cultivars. Two experiments were performed in the green house of the Center of Human and Agrarian Sciences of the Paraíba State University (CCHA-UEPB), Campus IV, Catolé do Rocha-PB. In the first experiment, an entirely randomized experimental design with five treatments [(saline -sodic soil without conditioners (SSC), saline -sodic soil + biofertilizer at 10% of the soil volume (SS + B), saline -sodic soil + chalk at 100% of the chalk requirement (SS + C), saline -sodic soil + chalk + biofertilizer (SS + C + B), and non-saline soil (NSL)] and eight replicates was adopted. In the second randomized experiment the treatments were displayed in a 5 × 2 factorial scheme, referring to the five corrective treatments used in the first experiment and the two castor bean plant cultivars (BRS Nordestina and BRS Paraguaçu), with four replicates. The application of chalk combined with biofertilizer promoted a better initial development of the castor bean plant in comparison with other recovering treatments. This indicates the corrective effect of chalk on sodicity and of both treatments on the nutrient availability for the plants. The bovine biofertilizer alone did not reduce the sodicity of the sodic -saline soil. Under the evaluated conditions, the BRS Nordestina surpassed the BRS Paraguaçu. Key words: Ricinus communis L., salinity, sodicity, soil correction ResumoO objetivo do trabalho foi estudar a aplicação de condicionadores de natureza química e orgânica nos atributos químicos de um solo salino-sódico e no crescimento inicial de duas cultivares de mamoneira. (Solo salino -sódico sem corretivo (SSC), Solo salino -sódico + biofertilizante à 10% do volume do solo (SS + B), Solo salino -sódico + gesso à 100% da necessidade de gesso (SS + G), Solo salino -sódico + gesso + biofertilizante (SS + G + B) e solo não salino (SNS)) com 8 repetições e, no segundo experimento, também conduzido em delineamento inteiramente casualizado, os tratamentos foram arranjados em esquema fatorial 5 x 2, referente aos cinco tratamentos de correção obtidos no primeiro experimento e duas cultivares de mamoneira (BRS Nordestina e BRS Paraguaçu), com quatro repetições. A Aplicação de gesso associado ao biofertilizante promoveu o maior desenvolvimento inicial das plantas de mamoneira quando comparado aos demais tratamentos de recuperação e indica ação positiva do gesso como corretivo da sodicidade e de ambos no aumento da disponibilidade de nutrientes às plantas. O biofertilizante bovino isolado não reduz a sodicidade do solo salino -sódico. Nas condições estudadas, a cultivar BRS Nordestina superou a BRS Paraguaçu.