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The scarce availability of good quality water for irrigation in semi-arid regions leads to the reuse of waters, such as reject brine. Associated with this, the use of alternatives, such as hydroponic cultivation in substrates suitable for the development of profitable crops, such as watermelon, a species considered moderately sensitive to salinity, will allow new opportunities for communities assisted by desalination plants. An experiment was conducted in a plastic greenhouse to evaluate the growth, physiological responses, yield, and fruit quality of ‘Sugar Baby’ mini-watermelon cultivated in a hydroponic system with reject brine from desalination plants and different substrates. The experimental design was randomized blocks, with treatments arranged in a 5 × 4 factorial scheme, corresponding to five mixtures of reject brine (9.50 dS m−1) and tap water (0.54 dS m−1) applied to mini-watermelon plants, in an open hydroponic system, with four types of substrate and four replicates, with two plants per plot. Mini-watermelon plants grown in coconut fiber substrate showed the best growth and production. On the other hand, washed sand was the substrate that most hampered the development of plants in all mixtures. The use of reject brine to prepare the nutrient solution reduced the growth and production of mini-watermelon, mainly in mixtures with salinity above 4.00 dS m−1. The changes in gas exchange caused by salt stress in mini-watermelon were of stomatal nature. Mini-watermelon has high energy stability under conditions of salt stress.

The viability of T. aurea seeds is evaluated through the germination test, taking 21 days, which makes it difficult to obtain quick information about the viability of its seeds. In this context, using the tetrazolium test as an evaluation method would be appropriate because it provides faster and more reliable information for several species. In view of the above, the objective of this study was to adapt the tetrazolium test methodology to evaluate the viability of T. aurea seeds. Initially, the imbibition curve was constructed to determine the appropriate hydration period for the seeds and the germination test was conducted, both for evaluating the initial quality and for comparison with the tetrazolium test results. For the tetrazolium test, the seeds were hydrated for 24 hours, then their coats were removed and the seeds were immersed in tetrazolium solutions. The concentrations used were 0.05, 0.075 and 0.1% for three staining periods 2, 4 and 6 hours, at 35 and 40 °C, in the absence of light. The experimental design was completely randomized in a 3 x 3 + 1 factorial scheme (three concentrations of tetrazolium solution x three staining periods + one control = germination test) with four replicates of 25 seeds. Tetrazolium test was adequate to evaluate the viability of T. aurea seeds using the concentration of 0.05% for four hours at 40 °C. RESUMO A avaliação da viabilidade de sementes de T. aurea é realizada por meio do teste de germinação, demorando 21 dias, o que dificulta a obtenção de informações rápidas sobre a viabilidade de suas sementes. Nesse sentido, a utilização do teste de tetrazólio como método de avaliação seria adequado por proporcionar informações com maior agilidade e confiável para várias espécies. Diante do exposto, objetivou-se adequar a metodologia do teste de tetrazólio para avaliar a viabilidade de sementes de T. aurea. Inicialmente, realizou-se a curva de embebição para determinar o período adequado de hidratação das sementes e o teste de germinação, tanto para avaliar a qualidade inicial, quanto para fins comparativos com os resultados do teste de tetrazólio. Para a instalação deste, as sementes foram hidratas por 24 horas, posteriormente, o tegumento foi removido e as sementes imersas em soluções de tetrazólio. As concentrações utilizadas foram de 0,05; 0,075 e 0,1% por três períodos de coloração 2, 4 e 6 horas, a 35 e 40 °C, em ausência de luz. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 3 x 3 + 1 (três concentrações da solução de tetrazólio x três períodos de coloração + uma testemunha = teste de germinação), com quatro repetições de 25 sementes. O teste de tetrazólio mostrou-se adequado para avaliar a viabilidade de sementes de T. aurea utilizando a concentração de 0,05%, por quatro horas, a 40 °C.

This study aimed to evaluate the effect of irrigation with saline water and phosphate fertilization on phytomass accumulation and tissue mineral composition of cowpea shoots. The research was carried out in a greenhouse utilizing randomized block design in a 5 x 3 factorial scheme consisting of five levels salinity of irrigation water (0.5 as control, 1.5, 2.5 3.5 and 4.5 dS m-1) and three doses of P2O5- (60, 100 and 140% from a recommended dose of 60 kg P2O5- ha-1), with 5 replicates. The plants were grown in pots up to flowering and then phytomass accumulation and mineral composition of cowpea (indicate cultivar name) shoot were measured. Irrigation with saline water from 0.8 dS m-1 reduced phytomass accumulation and mineral composition of cowpea plants, making the plants to be considered moderately tolerant up to EC 2.5 dS m-1. The 40% increase in recommended phosphorus dose promotes high iron and copper accumulations and, less sodium accumulation into tissues of cowpea shoot as influenced by saline stress. 60% reduction of the recommended dose of phosphate fertilizer increased the manganese and zinc accumulation of tissues of cowpea shoot under salt stress.

Salvia hispanica L. is an alternative crop cultivated by farmers who want to diversify their production. However, this species is sensitive to salinity, which affects its germination negatively. Seed priming with different attenuators is a technique with potential to mitigate the effects of salt stress. Thus, the objective of this study was to evaluate the effect of seed priming with the use of different attenuators on the germination, growth, and organic solute accumulation of S. hispanica seedlings under salt stress. The experimental design was completely randomized, with treatments distributed in a 4 × 5 factorial scheme, corresponding to four seed priming treatments and five osmotic potentials, with four replicates of 50 seeds in each treatment. The seed treatments consisted of presoaking seeds for 4h in salicylic acid, gibberellic acid, and distilled water and the control treatment, which did not involve soaking. These seeds were germinated at osmotic potentials of 0.0, -0.1, -0.2, -0.3, and -0.4 MPa, using NaCl as an osmotic agent to simulate the different salinity levels. Among all the treatments implemented, S. hispanica seed priming with salicylic acid was the most efficient in mitigating the salt stress effects. Salvia hispanica L. is an alternative crop cultivated by farmers who want to diversify their production. However, this species is sensitive to salinity, which affects its germination negatively. Seed priming with different attenuators is a technique with potential to mitigate the effects of salt stress. Thus, the objective of this study was to evaluate the effect of seed priming with the use of different attenuators on the germination, growth, and organic solute accumulation of S. hispanica seedlings under salt stress. The experimental design was completely randomized, with treatments distributed in a 4 × 5 factorial scheme, corresponding to four seed priming treatments and five osmotic potentials, with four replicates of 50 seeds in each treatment. The seed treatments consisted of presoaking seeds for 4h in salicylic acid, gibberellic acid, and distilled water and the control treatment, which did not involve soaking. These seeds were germinated at osmotic potentials of 0.0, -0.1, -0.2, -0.3, and -0.4 MPa, using NaCl as an osmotic agent to simulate the different salinity levels. Among all the treatments implemented, S. hispanica seed priming with salicylic acid was the most efficient in mitigating the salt stress effects.

The use of effluent from fish farming in the greenhouse increases the availability of water and reduces the risk of environmental contamination due to improper disposal. Therefore, a study in a greenhouse was carried out to evaluate the effects of fertigation utilizing fish farming effluent at different phenological stages of cherry tomato. Plants of cherry tomato were fertigated with fish farming effluent (E) alternated with tap water (W) at the four phenological stages of the crop (growth, flowering, fruit formation and ripening). The growth, gas exchange, chlorophyll a fluorescence, chloroplast pigments, electrolyte leakage, production and postharvest quality were evaluated. The fertigation with fish farming effluents did not reduce the growth of tomato plants. The fertirrigated plants with fish farming effluents obtained photosynthetic rates and photochemical efficiency similar or superior to the control. There was no interference on photochemical quenching when the plants were fertigated with fish farming effluents. When applied at the flowering stage, fish farming effluent reduces the average fruit weight and increases acidity. For greenhouse cultivation, each application of fish farming effluents, two successive applications of tap water are required.Novelty statement: Use of fish farming effluent did not compromise the growth and photosynthetic activity of cherry tomato plants. Cherry tomato production was compromised when the effluent was applied during growth, flowering and, beginning of fruit set. The fish farming effluent can be used in irrigation without yield losses if alternating with tap water.

Salt stress is the cause of low yield in many arid and semi-arid regions. Strategies to increase crop yields in salt stress conditions are very important, especially in systems with higher production costs, such as irrigated fruticulture. This study proposes to assess the photosynthetic efficiency and growth of Annona squamosa irrigated with saline water under different doses of nitrogen, phosphorus, and potassium fertilization. The assay was conducted in a greenhouse and consisted of two factors, which corresponded to two electrical conductivity of water (ECw) (0.8 and 3.0 dS m−1) and eight combinations of fertilization with nitrogen, phosphorus, and potassium ranging from 100 to 140% of the recommended dose, arranged in a 2 × 8 factorial scheme, with three replicates. Plants were evaluated for growth, chlorophyll a fluorescence, gas exchanges, and production over a period of 1 year. The photosynthetic efficiency in the vegetative stage of A. squamosa plants is the most affected by salt stress. Stomatal closure and damage to the quantum efficiency of photosystem II are the main factors responsible for the reduction of photosynthesis and growth. In the reproductive stage, A. squamosa plants acclimated to salt stress, with no effect of salinity on the photochemical efficiency and stomatal conductance, but the damage to photosynthesis was not reversed and contributed to reducing production. The fertilizer combination C6 (140:100:140% or 56:60:84 g plant−1 year−1 of N:P2O5:K2O) is recommended to mitigate salt stress and increase A. squamosa production.

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.

Water availability and substrate type are essential factors in seed germination tests, influencing imbibition and seedling development. The objective of this study was to evaluate the influence of two substrates and different water volumes on the germination and vigor of chia seeds. The experimental design was completely randomized in a 2 x 6 factorial scheme, which consisted of two substrates, paper towel (Germitest®) and blotting paper, soaked with six water volumes equivalent to 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 times their dry weight, in four replicates of 50 seeds each. Germination percentage, mean time of germination, shoot length, radicle length, shoot dry matter, radicle dry matter, total dry matter (seedling), and root/shoot ratio were evaluated. Based on our results, germination tests for seeds of chia should be conducted using blotting paper (on paper) as substrate, with a water volume of 2.5 to 4.0 times its dry weight. Chia seedlings grown on blotting paper showed greater growth and dry matter accumulation compared to those grown on paper towel. A disponibilidade de água e o tipo de substrato são requisitos essenciais para a condução do teste de germinação em sementes, por influenciarem na embebição e no desenvolvimento das plântulas. Objetivou-se avaliar a influência de dois substratos e diferentes volumes de água sob a germinação e vigor de sementes de chia. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 2 x 6, sendo dois substratos substratos de papel toalha (Germitest®) e mata-borrão umedecidos com seis volumes de água equivalentes a 1,5; 2,0; 2,5; 3,0; 3,5 e 4,0 vezes o seu peso seco, em quatro repetições de 50 sementes. Avaliou-se a percentagem e o tempo médio de germinação, comprimento da parte aérea e da radícula, massa seca da parte aérea, radícula e total (plântula) e a relação raiz/parte aérea. O teste de germinação de sementes de chia deve ser conduzido no substrato mata-borrão (sobre papel) com quantidade de água entre 2,5 a 4,0 vezes o peso do papel seco. As plântulas de chia oriundas do papel mata-borrão obtiveram maior crescimento e acúmulo de matéria seca em relação às do papel toalha.

The tetrazolium test is one of the promising alternatives to determine the viability of dormant, recalcitrant and slow-germinating seeds. The objective of this study was to adapt the tetrazolium test methodology to estimate the viability and vigor of Piptadenia stipulacea (Benth.) Ducke seeds. For this, a sample of seeds was classified into three sublots using round sieves, corresponding to six, five and four millimeters in diameter, respectively. Moisture content, imbibition curve, germination, emergence, germination and emergence speed indices, mean germination time and seedling emergence were initially evaluated. The second stage was conducted using a completely randomized experimental design, in 3 x 9 factorial scheme, corresponding to three sublots and nine combinations between concentrations and time of immersion in tetrazolium salt (0.05%/2 h; 0.05%/4 h; 0.05%/6 h; 0.075%/2 h; 0.075%/4 h; 0.075%/6 h; 0.1%/2 h; 0.1%/4 h; 0.1%/6 h), totaling twenty-seven treatments with four replicates of 25 seeds, evaluated separately at 35 and 40 °C. For each treatment, the seeds were divided into four classes: viable and vigorous seeds (class I), viable and non-vigorous (class II), unviable (class III) and dead (class IV). The period of 8 h of pre-imbibition and 4 h of staining in tetrazolium solution at 0.075%, under 35 or 40 °C, is adequate to estimate the viability and vigor of P. stipulacea seeds. RESUMO O teste de tetrazólio constitui uma das alternativas promissoras para determinar a viabilidade de sementes dormentes, recalcitrantes e de germinação lenta. Objetivou-se adequar a metodologia do teste de tetrazólio para estimar a viabilidade e vigor em sementes de Piptadenia stipulacea (Benth.) Ducke. Para isso, uma amostra de sementes foi classificada em três sublotes utilizando peneiras de crivo redondo, correspondendo a seis, cinco e quatro milímetros de diâmetro, respectivamente. Inicialmente, avaliou-se o teor de água, curva de embebição, germinação, emergência, índice de velocidade de germinação e emergência, tempo médio de germinação e emergência de plântulas. Na segunda etapa, utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 3 x 9, sendo três sublotes e nove combinações entre concentrações e tempo de imersão no sal de tetrazólio (0,05%/2 h; 0,05%/4 h; 0,05%/6 h; 0,075%/2 h; 0,075%/4 h; 0,075%/6 h; 0,1%/2 h; 0,1%/4 h; 0,1%/6 h), totalizando vinte e sete tratamentos com quatro repetições de 25 sementes, avaliados separadamente a 35 e 40 °C. Para cada tratamento, as sementes foram divididas em quatro classes: sementes viáveis e vigorosas (classe I), viáveis e não vigorosas (classe II), inviáveis (classe III) e mortas (classe IV). O período de 8 h de pré-embebição e 4 h de coloração na solução de tetrazólio a 0,075%, sob 35 ou 40 °C, é adequado para estimar a viabilidade e vigor de sementes de P. stipulacea.

Water availability and temperature are among the main abiotic factors that influence seed germination and vigor, since they act directly on biochemical and physiological processes, which result in the production of the primary root. The objective of this study was to verify the effects of stress on germination and vigor of H. impetiginosus (‘ipê-roxo’) seeds under different temperatures and osmotic agents. The experimental design was completely randomized, in a 6 x 2 factorial scheme (osmotic potentials x temperatures) with four replicates of 25 seeds for each osmotic agent. In order to simulate water stress, polyethylene glycol (PEG 6000) and mannitol solutions were used and distilled water was used as control. Osmotic potentials of 0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa were evaluated at temperatures of 25 and 30 °C, under 8 h photoperiod. The variables analyzed were: germination, germination speed index, shoot length, root length, and total dry matter of seedlings. Simulated water stress affected seed germination and seed vigor of H. impetiginosus at both temperatures and osmotic agents from -0.6 MPa. RESUMO A disponibilidade de água e temperatura estão entre os principais fatores abióticos que influenciam sobre a germinação e vigor de sementes, uma vez que atuam diretamente sobre processos bioquímicos e fisiológicos, que resultam na emissão da raiz primária. Dessa forma, objetivou-se verificar os efeitos do estresse hídrico sobre a germinação e vigor de sementes de H. impetiginosus (ipê-roxo) sob diferentes temperaturas e agentes osmóticos sob foto-período de 8 h. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 6 x 2, correspondente a seis níveis de potenciais osmóticos (0; -0,2; -0,4; -0,6; -0,8 e -1,0 MPa ) e duas temperaturas (25 e 30 ºC), com quatro repetições de 25 sementes para cada agente osmótico (polietileno glicol-PEG 6000 e manitol). As variáveis analisadas foram germinação, índice de velocidade de germinação, comprimento da parte aérea e da raiz e a massa seca total de plântulas. A germinação e o vigor de sementes de H. impetiginosus são comprometidos em condições de estresse hídrico, à medida que o potencial osmótico decresce, em ambas as temperaturas e agentes osmóticos a partir de -0,6 MPa.

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. RESUMO Objetivou-se avaliar a interação entre salinidade da água e doses de nitrogênio e fósforo sobre a fluorescência da clorofila a e o crescimento das plantas de aceroleira na fase inicial de crescimento. A pesquisa foi realizada em ambiente protegido, em lisímetros preenchidos com Neossolo Regolítico de textura franco-argilosa e baixo teor inicial de fósforo. O experimento foi instalado em delineamento de blocos casualizados, arranjados em esquema fatorial com dois fatores, sendo cinco níveis de condutividade elétrica da água de irrigação - CEa (0,6; 1,4; 2,2; 3,0 e 3,8 dS m-1) e quatro proporções da recomendação de fósforo nitrogênio -P/N (100:100; 140:100; 100:140 e140:140% P/N da recomendação), com três repetições sendo cada parcela foi constituída de uma planta. Água de salinidade superior à 2,2 dS m-1 diminui a eficiência quântica do fotossitema II e o crescimento das plantas de aceroleira. O incremento no fornecimento de nitrogênio e/ou fósforo melhora a estabilidade energética das plantas de acerola, reduzindo os efeitos do estresse salino sobre a eficiência quântica do fotossitema II. O incremento de 40% na dose de nitrogênio aumentou a florescência da clorofila a das plantas de acerola, porém não influenciou o crescimento das plantas.

This study aimed to evaluate the physiology and phytomass accumulation of sorghum plants, in saline-sodic soil treated with amendments and doses of single superphosphate. The experiment was conducted in the period from January to June 2013, in a greenhouse in the municipality of Pombal, Paraiba, Brazil, using samples of a saline-sodic soil. The experimental design was randomized blocks, in a 2 x 5 factorial scheme, relative to two types of amendments of sodic soil and 5 levels of single superphosphate, with 3 replicates, totaling 30 experimental units. Each plot was represented by two pots with capacity for 2 dm3 with one plant each. At 30 days after sowing, sorghum plants were evaluated for gas exchanges, chlorophyll a fluorescence and phytomass accumulation. Single superphosphate application positively stimulated the gas exchanges of sorghum plants at the doses of 97.9 mg dm-3, for the soil treated with gypsum, and 88.1 mg dm-3, for the soil treated with elemental sulfur. Soil treatment with agricultural gypsum promoted the highest levels of chlorophyll a fluorescence, in comparison to elemental sulfur treatment. Phytomass accumulation was favored by the single superphosphate, with highest accumulation when the dose of 75 mg dm-3 was applied.

The objective of this work was to study the effects of irrigation with saline water associated with phosphate fertilization on the emergence and early growth of cowpea plants. The assay was conducted in the greenhouse of the Department of Environmental Sciences and Technology of the Federal Rural University of the Semi-Arid (UFERSA) in Mossoró-RN, during October and November of 2015. The study adopted a randomized block with treatments arranged in a 5 x 3 grid, corresponding to five levels of water salinity (0.5, 1.5, 2.5, 3.5 and 4.5 dS m-1) and three doses of superphosphate, based upon the soil analysis (60%, 100% and 140% of the recommended dose for the crop 60 kg P2O5 ha-1), with five repetitions. The cowpea plants, cv. Paulistinha, were grown in lysimeters with capacity of 8 dm3. During the first 15 days of the initial stage of development the plants were evaluated for emergence, growth and biomass accumulation. The increase in water salinity above 1.5 dSm-1 reduced the emergence, growth and dry matter accumulation of cowpea plants. The increase of 40% in the recommendation of phosphorus fertilization of cowpea increased the growth and biomass accumulation of shoot plants, regardless of salinity. Resumo Objetivou-se estudar os efeitos da irrigação com água salina associada à adubação fosfatada com superfosfato simples na emergência e crescimento inicial de plantas de feijão-caupi. A pesquisa foi realizada em casa de vegetação do Departamento de Ciências Ambientais e Tecnológicas da Universidade Federal Rural do Semi-Árido (UFERSA), em Mossoró-RN, no período de outubro a novembro de 2015, no delineamento experimental de blocos casualizados com tratamentos arranjados em esquema fatorial 5 x 3, relativos a cinco níveis de salinidade da água (0,5; 1,5; 2,5; 3,5 e 4,5 dS m-1) e três doses de superfosfato simples, tendo como base a análise de solo (60%, 100% e 140% da dose recomendada para a cultura- 60 kg P2O5 ha-1), com cinco repetições. As plantas de feijão-caupi cv. Paulistinha foram cultivadas em lisímetros com capacidade de 8 dm3. Durante os primeiros 15 dias da fase inicial de desenvolvimento, as plantas foram avaliadas quanto à emergência, crescimento e acúmulo de biomassa. O aumento da salinidade da água de irrigação acima de 1,5 dS m-1 reduziu a emergência, o crescimento e o acúmulo de massa seca das plantas de feijão-caupi. O incremento de 40% na recomendação da adubação fosfatada do feijão-caupi promoveu incrementos no crescimento e no acúmulo de biomassa da parte aérea da planta, independente da salinidade.

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. RESUMO Objetivou-se avaliar o efeito do condicionamento fisiológico com ácido salicílico na mitigação dos estresses hídrico e salino em sementes de cebola (Allium cepa L.). Para isto, sementes de cebola, cultivar IPA 11, foram embebidas em solução de ácido salicílico (50 µM) por 24 h e colocadas para germinar em diferentes potenciais hídricos e salinos. Para o estresse hídrico, o experimento foi conduzido em delineamento inteiramente casualizado, em esquema fatorial 2 x 5 (ácido salicílico com 0 e 50 µM e potenciais osmóticos de 0; -0,1; -0,2; -0,3; -0,4 MPa induzidos por polietilenoglicol 6000), com quatro repetições de 50 sementes por parcela. No estresse salino, adotou-se o delineamento experimental inteiramente ao acaso, com os tratamentos distribuídos em esquema fatorial 2 x 4 (ácido salicílico nas concentrações de 0 e 50 µM e os potenciais osmóticos de 0; -0,3; -0,6; -0,9 MPa induzidos por NaCl), em quatro repetições de 50 sementes. Para ambos os experimentos, avaliou-se a germinação, o crescimento e o acúmulo de solutos orgânicos. O ácido salicílico não estimulou a germinação de sementes de cebola na ausência de estresse, mas a aplicação de 50 µM de ácido salicílico incrementou a velocidade de germinação, o crescimento e o acúmulo de matéria seca em condições de estresse hídrico e salino. As plantas de cebola foram eficientes em realizar ajustamento osmótico até os potenciais de -0,2 MPa induzidos por PEG 6000 no estresse hídrico, e de -0,4 MPa induzido por NaCl no estresse salino.

Salvia hispanica seedlings have stood out for their potentialities in nutrients for agri-food industries. Nevertheless, studies related to this species are still scarce, especially with respect to agronomic factors that enable its propagation and development. Hence, this study aimed to evaluate germination, vigor and osmotic adjustment of S. hispanica seeds and seedlings subjected to water and thermal stress. The experimental design was completely randomized, with treatments arranged in factorial scheme, corresponding to five levels of polyethylene glycol (PEG 6000) (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and five temperatures (20, 25, 30 and 20-30 °C), with four replicates of 50 seeds in each treatment. Germination test was set on blotter paper, moistened with PEG 6000 solutions at the previously mentioned potentials, under 8-h photoperiod. The following variables were analyzed: germination, germination speed index, seedling shoot length, seedling root length, seedling dry matter and contents of chlorophyll, carotenoids, amino acids, proline and sugars. Polyethylene glycol levels of -0.4 MPa at all temperatures and -0.3 MPa at 30 °C and 20-30 °C enable germination and vigor of S. hispanica seedlings. S. hispanica seedlings are able to perform osmotic adjustment under water stress conditions up to the level of -0.3 MPa, when grown from seeds germinated at temperatures of up to 25 ºC. As sementes de S. hispanica têm se destacado pela sua potencialidade em nutrientes para as indústrias agroalimentares. No entanto, ainda são escassas as pesquisas relacionadas a esta espécie, principalmente no tocante aos fatores agronômicos que viabilizem a sua propagação e desenvolvimento. Com isso, objetivou-se verificar a germinação, vigor e ajustamento osmótico de sementes e plântulas de S. hispanica submetidas aos estresses hídrico e térmico. O delineamento experimental foi o inteiramente casualizado, com tratamentos distribuídos em esquema fatorial, correspondente a cinco níveis de polietileno glicol (PEG 6000) (0,0; -0,1; -0,2; -0,3 e -0,4 MPa) e quatro temperaturas (20, 25, 30 e 20-30 °C), com quatro repetições de 50 sementes para cada tratamento. Para isso, instalou-se o teste de germinação em substrato mata-borrão, umedecidos com soluções de PEG 6000 nos potenciais mencionados, sob fotoperíodo de 8 horas de luz. As variáveis analisadas foram germinação, índice de velocidade de germinação, comprimento de parte aérea e das raízes das plântulas, massa seca de plântulas, teores de clorofila e carotenoides, aminoácidos, prolina e açúcares. O nível de polietilenoglicol de -0,4 MPa para todas as temperaturas estudadas, e -0,3 MPa nas temperaturas de 30 °C e 20-30 °C inviabilizam a germinação e o vigor das plântulas de S. hispanica. As plântulas de S. hispanica são capazes de realizar ajuste osmótico sob condições de estresse hídrico até os níveis de -0,3 MPa, quando provenientes de sementes germinadas em temperaturas de até 25 ºC.

Salinity is one of the main causes of crop yield decline in arid and semi-arid regions, requiring the use of tolerant species that allow cultivation in these areas. The objective of this study was to determine the emergence, initial growth and tolerance of pepper species irrigated with saline waters. The experiment was conducted in a protected environment (greenhouse), with a 5 x 3 factorial scheme, using four replicates of 30 seeds each. The experimental design was a completely randomized design, involving five irrigation water salinity levels (0.6, 1.2, 1.8, 2.4 and 3.0 dS m-1) and three species of pepper [E1 - Capsicum annuum (“Doce Comprida”); E2 - Capsicum frutescens (“Malagueta”); E3 - Capsicum chinense (“De Bico”)]. Pepper seedlings were grown in trays of 30 cells with a capacity of 0.1 dm3 of substrate. During the first 30 days after sowing, seedlings were monitored for emergence, initial growth and dry matter accumulation. As the salinity of the irrigation water increased, there was a reduction in the emergence, growth and phytomass accumulation of C. annuum, C. frutescens and C. chinense peppers. These species tolerate saline waters of up to 1.78, 2.71 and 1.55 dS m-1 respectively, in the initial development phase, with C. frutescens being the most tolerant to saline stress, and C. chinense the most sensitive. RESUMO A salinidade é uma das principais causas da queda de rendimento das culturas, em regiões áridas e semiáridas, sendo necessária a utilização de espécies tolerantes que viabilizem o cultivo nestas áreas. Nesse sentido, objetivou-se verificar a emergência, o crescimento inicial e a tolerância de espécies de pimenta irrigadas com águas salinas. O experimento foi conduzido em ambiente protegido (casa de vegetação), sendo os tratamentos formados a partir do esquema fatorial 5 x 3, usando-se quatro repetições de trinta sementes. O delineamento experimental foi o inteiramente casualizado, relativos a cinco níveis de salinidade da água de irrigação (0,6; 1,2; 1,8; 2,4 e 3,0 dS m-1) e três espécies de pimenta [E1 - Capsicum annuum (“Doce Comprida”); E2 - Capsicum frutescens (“Malagueta”); E3 - Capsicum chinense (“De Bico”)]. As plântulas de pimenta foram cultivadas em bandejas de 30 células com capacidade de 0,1 dm3 de substrato, durante 30 dias após a semeadura. Nesse período, as plântulas foram monitoradas quanto à emergência, o crescimento inicial e o acúmulo de matéria seca. O aumento da salinidade da água de irrigação reduz a emergência, o crescimento e o acúmulo de fitomassa das pimentas C. annuum, C. frutescens e C. chinense. As espécies C. annuum, C. frutescens e C. chinense toleram CEa de até 1,78, 2,71 e 1,55 dS m-1 na fase de desenvolvimento inicial, respectivamente, sendo a C. frutescens a mais tolerante ao estresse salino, e a C. chinense, a mais sensível dentre as espécies verificadas.

CRESCIMENTO E TROCAS GASOSAS DO FEIJÃO CAUPI CV. BRS PUJANTE SOB NÍVEIS DE ÁGUA DISPONÍVEL NO SOLO E COBERTURA MORTA TARSO MORENO ALVES DE SOUZA1; TÁSSIO ALMEIDA SOUZA1; LAUTER SILVA SOLTO2; FRANCISCO VANIES DA SILVA SÁ3; EMANOELA PEREIRA DE PAIVA4; MARCOS ERIC BARBOSA BRITO2 E EVANDRO FRANKLIN DE MESQUITA5 1Graduando em agrônomia, Unidade Acadêmica de Ciências Agrárias, Universidade Federal deCampina Grande, Pombal, PB. E-mail: tarsomoreno.agro@gmail.com; tassiobuzu@hotmail.com.2Eng. Agrônomo, Doutor, Professor da Unidade Acadêmica de Ciências Agrárias, Universidade Federal deCampina Grande, Pombal, PB. E-mail: lauter@ccta.ufcg.edu.br; marcoseric@ccta.ufcg.edu.br .3Engenheiro Agrônomo, Doutorando em Engenharia Agrícola, Universidade Federal de Campina Grande – UFCG, Centro Tecnologia e Recursos Naturais – CTRN, Campina Grande - PB, Brasil. E-mail: vanies_agronomia@hotmail.com.4 Eng. Agrônoma, Doutoranda em Fitotecnia, Departamento de Ciências Vegetais, Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, RN. E-mail: emanuelappaiva@hotmail.com.5Engenheiro Agrônomo, Doutor, Professor Adjunto, Centro de Ciências Humanas e Agrarias (CCHA), Universidade Estadual da Paraíba (UEPB), Catolé do Rocha, PB, e-mail: elmesquita4@uepb.edu.br. 1 RESUMO O feijão-caupi é amplamente cultivado em regiões áridas e semiáridas, onde o déficit hídrico é um fator limitante à produção das culturas, sendo necessária adoção de práticas que melhorem o desempenho da cultura. Com isso, objetivou-se avaliar o efeito de níveis de água disponível no solo com e sem cobertura morta sobre a superfície do solo, sob o crescimento e atividade fotossintética do feijão Caupi (Vigna unguiculata Walp.), cv. BRS Pujante. O trabalho foi desenvolvido no Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande, usando-se um delineamento experimental inteiramente casualizado, com tratamentos arranjados em esquema fatorial, 5 x 2, correspondentes aos níveis de água disponível (AD) de 20; 40; 60; 80 e 100%, mantido após as irrigações do solo, em função da cobertura morta (CC) e sem cobertura (SC), e quatro repetições, totalizando as 40 unidades experimentais. Aos 45 dias as plantas de feijão caupi foram avaliadas quanto ao crescimento e trocas gasosas. O maior crescimento em número de folhas e área foliar da cultivar BRS Pujante ocorre em cultivos com água disponível no solo acima de 75%. A cobertura do solo reduziu os efeitos do estresse hídrico sob o crescimento das plantas. O mecanismo de tolerância das plantas da cultivar BRS Pujante está relacionado à redução do número de folhas e da área foliar e o aumento das trocas gasosas nas folhas restantes. As plantas de feijão Caupi cultivar BRS Pujante apresentam altos índices de eficiência do uso da água sob condições de baixa disponibilidade hídrica. Palavras-chave: semiárido, deficit hídrico, fisiologia. SOUZA, T. M. A. de; SOUZA, T. A.; LAUTER SILVA SOLTO; SÁ, F. V. da S.; PAIVA, E. P. de; BRITO, M. E. B.2 E MESQUITA, E. F. deGROWTH AND GAS EXCHANGE OF COWPEA CV. BRS PUJANTE BEAN UNDER LEVELS OF AVAILABLE WATER IN THE SOIL AND MULCH2 ABSTRACT Cowpea is widely cultivated in arid and semiarid regions, where drought is a limiting factor to crop production, requiring the adoption of practices to improve the culture performance. In this context, the study was intended to assess the effect of levels of available water in the soil with and without mulch on the soil surface, in the growth and photosynthetic activity of Cowpea (Vigna unguiculata Walp.), cv. BRS Pujante bean. The study was conducted at the Centre for Science and Agrifood Technology of Federal University of Campina Grande, using a completely randomized design, with treatments arranged in a factorial scheme 5 x 2, corresponding to the levels of available water (AD) 20; 40; 60; 80 and 100%, maintained after soil irrigations, as function of mulch (CC) and without cover (SC) and four repetitions, totaling the 40 experimental units. After 45 days the cowpea plants were evaluated for growth and gas exchange. The highest growth in number of leaves and leaf area of BRS Pujante occurs in crops with water available in the soil above 75%. The soil cover reduced the effects of water stress on plant growth. The mechanism of tolerance of BRS Pujante plants is associated to the reduction of the number of leaves and leaf area and the increase of gas exchange in the remaining leaves. The cowpea cultivar BRS Pujante presents high levels of water use efficiency under conditions of low water availability. Keywords: semiarid, water deficit, physiology.