Hydrogen Peroxide Alleviates Salt Stress Effects on Gas Exchange, Growth, and Production of Naturally Colored Cotton.

Cotton is one of the most exploited crops in the world, being one of the most important for the Brazilian Northeast. In this region, the use of irrigation is often necessary to meet the water demand of the crop. Water is often used from underground wells that have a large amount of salt in their constitution, which can compromise the development of crops, so it is vital to adopt strategies that reduce salt stress effects on plants, such as the foliar application of hydrogen peroxide. Thus, the objective of this study was to evaluate the effects of foliar application of hydrogen peroxide on the gas exchange, growth, and production of naturally colored cotton under salt stress in the semi-arid region of Paraíba, Brazil. The experiment was carried out in a randomized block design in a 5 × 5 factorial scheme, with five salinity levels of irrigation water-ECw (0.3, 2.0, 3.7, 5.4 and 7.1 dS m-1)-and five concentrations of hydrogen peroxide-H2O2 (0, 25, 50, 75 and 100 µM), and with three replicates. The naturally colored cotton 'BRS Jade' had its gas exchange, growth, biomass production, and production reduced due to the effects of salt stress, but the plants were able to produce up to the ECw of 3.97 dS m-1. Foliar application of hydrogen peroxide at the estimated concentrations of 56.25 and 37.5 µM reduced the effects of salt stress on the stomatal conductance and CO2 assimilation rate of cotton plants under the estimated ECw levels of 0.73 and 1.58 dS m-1, respectively. In turn, the concentration of 12.5 µM increased water-use efficiency in plants subjected to salinity of 2.43 dS m-1. Absolute and relative growth rates in leaf area increased with foliar application of 100 µM of hydrogen peroxide under ECw of 0.73 and 0.3 dS m-1, respectively. Under conditions of low water salinity (0.3 dS m-1), foliar application of hydrogen peroxide stimulated the biomass formation and production components of cotton.

Water-Retaining Polymer and Planting Pit Size on Chlorophyll Index, Gas Exchange and Yield of Sour Passion Fruit with Deficit Irrigation.

Water availability is a limiting factor for the cultivation of sour passion fruit. Soil management techniques and the use of water-retaining polymers can increase soil water retention, reducing the frequency of irrigation in the crop. In this context, the objective of the research was to evaluate the gas exchange, the chlorophyll index, and the yield of the sour passion fruit cv. BRS GA1 as a function of irrigation depths, pit volumes, and doses of water-retaining polymer. The experiment was carried out in randomized blocks, in plots subdivided in a 2 × (2 × 5) arrangement, with irrigation depths of 70 and 100% of the crop evapotranspiration (ETc) as the main plot, the subplots with the volumes of pit of 64 and 128 dm3, and doses of the water-retaining polymer of 0, 0.5, 1.0, 1.5, and 2.0 g dm-3. The interaction of irrigation depths × pit volumes × doses of water-retaining polymer influences chlorophyll indexes, gas exchange, and water productivity, with positive impacts on yield of the sour passion fruit. The water depth of 70% of ETc increased the yield of sour passion fruit, in pits of 64 dm3. The application of doses of up to 1.1 g dm-3 of the water-retaining polymer and irrigation with water of 70% of ETc is recommended, and a dose of 2.0 g dm-3 of the water-retaining polymer in a pit volume of 128 dm3, associated with an irrigation depth of 100% ETc causes stress in sour passion fruit plants due to excess water.

The Effects of Irrigation Water Salinity on the Synthesis of Photosynthetic Pigments, Gas Exchange, and Photochemical Efficiency of Sour Passion Fruit Genotypes.

The objective of this study was to evaluate the synthesis of photosynthetic pigments, gas exchange, and photochemical efficiency of sour passion fruit genotypes irrigated with saline water under the conditions of the semi-arid region of Paraíba state, Brazil. The experiment was conducted at the experimental farm in São Domingos, PB. A randomized block design was adopted, in a 5 × 3 factorial scheme, with five levels of electrical conductivity of irrigation water-ECw (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1)-and three genotypes of sour passion fruit (Gigante Amarelo-'BRS GA1'; Sol do Cerrado-'BRS SC1'; and Catarina-'SCS 437'. The increase in the electrical conductivity of irrigation water negatively affected most of the physiological characteristics of the sour passion fruit at 154 days after transplanting. Significant differences were observed between sour passion fruit genotypes when its tolerance was subjected to the salinity of irrigation water. There was an increase in the percentage of damage to the cell membrane with the increase in the electrical conductivity of irrigation water, with maximum values of 70.63, 60.86, and 80.35% for the genotypes 'BRS GA1', 'BRS SC1', and SCS 437', respectively, when irrigated with water of 3.5 dS m-1. The genotype 'BRS Sol do Cerrado' showed an increase in the synthesis of photosynthetic pigments when irrigated with water of 3.5 dS m-1, with maximum values estimated at 1439.23 µg mL-1 (Chl a); 290.96 µg mL-1 (Chl b); 1730.19 µg mL-1 (Chl t); and 365.84 µg mL-1 (carotenoids). An increase in photosynthetic efficiency parameters (F0, Fm, and Fv) of the genotype 'BRS Gigante Amarelo' was observed when cultivated with water with high electrical conductivity (3.5 dS m-1).

Horticultural Crops under Stresses.

Climate change causes alterations in the spatio-temporal temperature and rainfall distribution [...].

Foliar Applications of Salicylic Acid on Boosting Salt Stress Tolerance in Sour Passion Fruit in Two Cropping Cycles.

Brazil stands out as the largest producer of sour passion fruit; however, the water available for irrigation is mostly saline, which can limit its cultivation. This study was carried out with the objective of evaluating the effects of salicylic acid in the induction of tolerance in sour passion fruit to salt stress. The assay was conducted in a protected environment, using a completely randomized design in a split-plot scheme, with the levels of electrical conductivity of the irrigation water (0.8, 1.6, 2.4, 3.2, and 4.0 dS m-1) considering the plots and concentrations of salicylic acid (0, 1.2, 2.4, and 3.6 mM) the subplots, with three replications. The physiological indices, production components, and postharvest quality of sour passion fruit were negatively affected by the increase in the electrical conductivity of irrigation water, and the effects of salt stress were intensified in the second cycle. In the first cycle, the foliar application of salicylic acid at concentrations between 1.0 and 1.4 mM partially reduced the harmful effects of salt stress on the relative water content of leaves, electrolyte leakage, gas exchange, and synthesis of photosynthetic pigments, in addition to promoting an increase in the yield and quality parameters of sour passion fruit.

Irrigation Strategies with Controlled Water Deficit in Two Production Cycles of Cotton.

Water scarcity is one of the main abiotic factors that limit agricultural production. In this sense, the identification of genotypes tolerant to water deficit associated with irrigation management strategies is extremely important. In this context, the objective of this study was to evaluate the morphology, production, water consumption, and water use efficiency of colored fiber cotton genotypes submitted to irrigation strategies with a water deficit in the phenological phases. Two experiments were conducted in succession. In the first experiment, a randomized block design was used in a 3 × 7 factorial scheme, corresponding to three colored cotton genotypes (BRS Rubi, BRS Jade, and BRS Safira) in seven irrigation management strategies with 40% of the real evapotranspiration (ETr) varying the phenological stages. In the second experiment, the same design was used in a 3 × 10 factorial arrangement (genotypes × irrigation management strategies). The water deficit in the vegetative phase can be used in the first year of cotton cultivation. Among the genotypes, 'BRS Jade' is the most tolerant to water deficit in terms of phytomass accumulation and fiber production.

Effect of Hydrogen Peroxide Application on Salt Stress Mitigation in Bell Pepper (Capsicum annuum L.).

The present study aimed to evaluate the effects of the foliar application of hydrogen peroxide on the attenuation of salt stress on the growth, photochemical efficiency, production and water use efficiency of 'All Big' bell pepper plants. The experiment was conducted under greenhouse conditions in Campina Grande, PB, Brazil. Treatments were distributed in a randomized block design, in a 5 × 5 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water (0.8, 1.2, 2.0, 2.6 and 3.2 dS m-1) and five concentrations of hydrogen peroxide (0, 15, 30, 45 and 60 µM), with three replicates. Foliar application of hydrogen peroxide at concentration of 15 µM attenuated the deleterious effects of salt stress on photochemical efficiency, biomass accumulation and production components of bell pepper plants irrigated using water with an electrical conductivity of up to 3.2 dS m-1. Foliar spraying of hydrogen peroxide at a concentration of 60 µM intensified the effects of salt stress. The 'All Big' bell pepper was classified as moderately sensitive to salt stress, with an irrigation water salinity threshold of 1.43 dS m-1 and a unit decrease of 8.25% above this salinity level.

Salicylic Acid as a Salt Stress Mitigator on Chlorophyll Fluorescence, Photosynthetic Pigments, and Growth of Precocious-Dwarf Cashew in the Post-Grafting Phase.

Salicylic acid is a phytohormone that has been used to mitigate the effects of saline stress on plants. In this context, the objective was to evaluate the effect of salicylic acid as a salt stress attenuator on the physiology and growth of precocious-dwarf cashew plants in the post-grafting phase. The study was carried out in a plant nursery using a randomized block design in a 5 × 4 factorial arrangement corresponding to five electrical conductivity levels of irrigation water (0.4, 1.2, 2.0, 2.8, and 3.6 dS m-1) and four salicylic acid concentrations (0, 1.0, 2.0, and 3.0 mM), with three replications. Irrigation water with electrical conductivity levels above 0.4 dS m-1 negatively affected the relative water content in the leaf blade, photosynthetic pigments, the fluorescence of chlorophyll a, and plant growth and increased electrolyte leakage in the leaf blade of precocious-dwarf cashew plants in the absence of salicylic acid. It was verified through the regression analysis that salicylic acid at a concentration of 1.1 mM attenuated the effects of salt stress on the relative water content and electrolyte leakage in the leaf blade, while the concentration of 1.7 mM increased the synthesis of photosynthetic pigments in precocious-dwarf cashew plants.

Production and Fiber Characteristics of Colored Cotton Cultivares under Salt Stress and H2O2.

Salt stress reduces the yield and quality of colored fiber cotton production, but this problem can be mitigated by the foliar application of hydrogen peroxide in adequate concentrations. In this context, the objective of the present study was to evaluate the production and characteristics of fibers of naturally colored cotton cultivares under irrigation with low- and high-salinity water and leaf application of hydrogen peroxide. The experiment was carried out in a greenhouse under a randomized block design, arranged in 4 × 3 × 2 factorial scheme, corresponding to four concentrations of hydrogen peroxide (0, 25, 50, and 75 µM), three cultivares of colored fiber cotton ('BRS Rubi', 'BRS Topázio', and 'BRS Verde'), and two electrical conductivities of water (0.8 and 5.3 dS m-1), with three replicates and one plant per plot. Irrigation with water of 0.8 dS m-1 associated with a foliar application of 75 µM of hydrogen peroxide favored the lint and seed weight, strength, micronaire index, and maturity of 'BRS Topázio'. The 'BRS Rubi' cotton cultivar showed higher tolerance to salinity, followed by the 'BRS Topázio' and 'BRS Verde' cultivares regarding the yield of seed cotton weight, with reduction below 20% under water of 5.3 dS m-1.

NPK Accumulation, Physiology, and Production of Sour Passion Fruit under Salt Stress Irrigated with Brackish Water in the Phenological Stages and K Fertilization.

This research aimed to evaluate the effects of salt stress, varying the phenological stages, and K fertilization on NPK concentrations, physiology, and production of Passiflora edulis Sims. The research was carried out at the University Farm of São Domingos, Paraíba, Brazil, using a randomized block design with a 6 × 2 factorial arrangement. Six irrigation strategies were evaluated (use of low electrical conductivity water (0.3 dS m-1) during all stages of development and application of high-salinity water (4.0 dS m-1) in the following stages: vegetative, flowering, fruiting, successively in the vegetative/flowering, and vegetative/fruiting stages) and two potassium levels (207 and 345 g K2O per plant), with four replications and three plants per plot. The leaf concentrations of N, P, and K in the sour passion fruit plants found in the present study were below the optimal levels reported in the literature, regardless of the development stage and the cultivation cycle. The relative water content, stomatal conductance, and photosynthesis were reduced by salt stress in the first cycle. However, in the second cycle, irrigation with 4.0 dS m-1 in the vegetative/flowering stages increased the CO2 assimilation rate. Passion fruit is sensitive to salt stress in the vegetative/flowering stages of the first cycle. In the second cycle, salt stress in the fruiting stage resulted in higher production per plant.

Osmoregulatory and Antioxidants Modulation by Salicylic Acid and Methionine in Cowpea Plants under the Water Restriction.

Global climate changes have intensified water stress in arid and semi-arid regions, reducing plant growth and yield. In this scenario, the present study aimed to evaluate the mitigating action of salicylic acid and methionine in cowpea cultivars under water restriction conditions. An experiment was conducted in a completely randomized design with treatments set up in a 2 × 5 factorial arrangement corresponding to two cowpea cultivars (BRS Novaera and BRS Pajeú) and five treatments of water replenishment, salicylic acid, and methionine. After eight days, water stress decreased the Ψw, leaf area, and fresh mass and increased the total soluble sugars and catalase activity in the two cultivars. After sixteen days, water stress increased the activity of the superoxide dismutase and ascorbate peroxidase enzymes and decreased the total soluble sugars content and catalase activity of BRS Pajeú plants. This stress response was intensified in the BRS Pajeú plants sprayed with salicylic acid and the BRS Novaera plants with salicylic acid or methionine. BRS Pajeú is more tolerant to water stress than BRS Novaera; therefore, the regulations induced by the isolated application of salicylic acid and methionine were more intense in BRS Novaera, stimulating the tolerance mechanism of this cultivar to water stress.

Salinity and Mulching Effects on Nutrition and Production of Grafted Sour Passion Fruit.

The Brazilian semiarid region stands out in terms of sour passion fruit production. Local climatic conditions (high air temperature and low rainfall), combined with its soil properties (rich in soluble salts), increase salinity effects on plants. This study was carried out in the experimental area "Macaquinhos" in Remígio-Paraíba (Brazil). The aim of this research was to evaluate the effect of mulching on grafted sour passion fruit under irrigation with moderately saline water. The experiment was conducted in split-plots in a 2 × (2 × 2) factorial scheme to evaluate the effects of the combination of irrigation water salinity of 0.5 dS m-1 (control) and 4.5 dS m-1 (main plot), passion fruit propagated by seed and grafted onto Passiflora cincinnata, with and without mulching (subplots), with four replicates and three plants per plot. The foliar Na concentration in grafted plants was 90.9% less than that of plants propagated via seeds; however, it did not affect fruit production. Plastic mulching, by reducing the absorption of toxic salts and promoting greater absorption of nutrients, contributed to greater production of sour passion fruit. Under irrigation with moderately saline water, the plastic film in the soil and seed propagation promote higher production of sour passion fruit.

Influence of Foliar Application of Hydrogen Peroxide on Gas Exchange, Photochemical Efficiency, and Growth of Soursop under Salt Stress.

Hydrogen peroxide at low concentrations has been used as a salt stress attenuator because it induces a positive response in the antioxidant system of plants. This study aimed to assess the gas exchange, quantum yield, and development of soursop plants cv. Morada Nova grown with saline water irrigation and foliar hydrogen peroxide application. The experiment was carried out under greenhouse conditions using a randomized block design in a 4 × 4 factorial scheme corresponding to four levels of electrical conductivity of irrigation water, ECw (0.8, 1.6, 2.4, and 3.2 dS m-1), and four doses of hydrogen peroxide, H2O2 (0, 10, 20, and 30 µM), with three replicates. The use of irrigation water with electrical conductivity above 0.8 dS m-1 inhibited stomatal conductance, internal CO2 concentration, transpiration, maximum fluorescence, crown height, and vegetative vigor index of the Morada Nova cultivar of soursop. Compared to untreated plants, the hydrogen peroxide concentration of 30 µM resulted in greater stomatal conductance. Water salinity of 0.8 dS m-1 with hydrogen peroxide concentrations of 16 and 13 µM resulted in the highest variable fluorescence and quantum efficiency of photosystem II, respectively, of soursop plants cv. Morada Nova at 210 days after transplantation.

Propagation of yellow passion fruit seedlings by cutting, grafting and seeds under salt stress

Salinity is one of the most limiting abiotic stresses in the global agricultural sector. The objective of this study was to evaluate the effect of irrigation water salinity on the initial development of P. edulis Sims. seedlings propagated by seeds, grafting and cuttings. Treatments were distributed in a completely randomized design, in a 5 x 3 factorial arrangement, corresponding to 5 levels of irrigation water electrical conductivity (0.3 - control, 1.8, 3.3, 4.8, and 6.3 dS m-1) and 3 propagation methods (seeds, cuttings and grafting), with four replicates and one plant per plot. Fifty days after the imposition of treatments with saline water, plant height, number of leaves, stem diameter, total chlorophyll, stomatal conductance, relative leaf water content, total water consumption, dry matter of root, shoot and total, root length and root volume were evaluated. The increase in water salinity affected with greater intensity the growth and development variables (height, total dry matter and root volume of the plant) and the physiological characteristics (stomatal conductance) of the species Passiflora edulis, regardless of the method of propagation. Seedlings propagated by grafting showed better development compared to the other propagation methods (seeds and cuttings). The interaction between the propagation methods and water salinity affected seedlings propagated by seeds and cuttings with greater intensity.

Productive characteristics of sunflower genotypes irrigated with different levels of saline water

Sunflower is suitable for family farmers from Northeast Brazil who are benefited by the production of grain and oil and is adequate for crop rotation and for honey production. The need for irrigation in this region leads to the realization of this study for evaluating the production components of four sunflower genotypes irrigated with different levels of water salinity. The study was carried out in the municipality of Remigio, Paraíba, Brazil, using a randomized block with split plots experimental design in a 5 x 4 factorial arrangement. Treatments consisted of five electrical conductivity levels of the irrigation water at 25 °C (L1 - 0.14 (reservoir water), L2 - 1.50, L3 - 2.50, L4 - 3.50, and L5 - 4.50 dS m- 1), and four sunflower genotypes (C1 - Embrapa 122-V2000, C2 - Olisun 03, C3 - AG 963, and C4 - Multissol) with three replicates. The irrigation water salinity levels tested did not influence the variables studied. Different values of the variables among sunflower genotypes were due to characteristics inherent to each genotype. Sunflower genotype Olisun 03 presented the highest oil content, while the lowest content was observed in Multissol.

Biomass and essential oil production of basil at recirculation intervals of nutrient solutions prepared with treated domestic effluents

Considering the growing water crisis, using wastewater helps reduce the pressure on good-quality water consumption. In this context, this study aimed to evaluate the growth, production, and essential oil content of Alfavaca Basilicão and Grecco a Palla basil genotypes with a DFT (deep flow technique) hydroponic system adapted to PVC tubes at different recirculation intervals of nutrient solutions prepared with treated domestic effluents. The experiment was performed in a greenhouse with Alfavaca Basilicão and Grecco a Palla basil genotypes analyzed individually. It was a completely randomized design with four replicates in a 2 x 3 factorial scheme: two types of water (public-supply water and wastewater) and three recirculation intervals of nutrient solutions (2, 4, and 6 hours). At 35 days after transplanting, the study evaluated plant height, stem diameter, shoot fresh mass, shoot dry mass, water consumption, water use efficiency, and essential oil content and yield. The types of water did not significantly influence the variables of growth, production, and essential oil content of the basil genotypes. Basil cultivation with the DFT system in tubes is technically feasible with nutrient solutions prepared with treated domestic effluents and recirculation every 2 and 6 hours for Grecco a Palla and Alfavaca Basilicão genotypes, respectively. The means of essential oil content were 1.6 and 1.7% (v/m) for Alfavaca Basilicão and Grecco a Palla genotypes, respectively.

Melon cultivation irrigated with saline waters promote chemical alterations in an acrisol / Cultivo de melão irrigado com águas salinas promove alterações químicas em argissolo

The objective of the present study was to evaluate the salinization process and the changes in the chemical properties of an Acrisol cultivated with melon irrigated with water of different saline concentrations. The experiment was carried out in the field conditions using the experimental design of randomized blocks, arranged in split-plot. The plots were composed of salinity levels of irrigation water, expressed in terms of water electrical conductivity (ECw): 0.54; 1.48; 2.02 dS m-1; and the sub-plots for melon cultivars: Sancho and Medellín (Toad Skin), Mandacaru (Yellow), Nectar (Galia) and Sedna (Cantaloupe). Soil samples were collected at the beginning and end of the crop cycle to evaluate the changes in the physical-chemical properties of the soil. The electrical conductivity of saturation extract in the soil profile varied for each cultivar, observing high salinity values in soils with cultivars with lower water demand (Sedna and Nectar). The salinity of the soil was lower than the electrical conductivity of the irrigation water in the treatments with high values of ECw. The soil pH values showed little reaction in relation to the initial values. The exchangeable sodium percentage values were approximate twice the sodium adsorption ratio of the saturation stratum.(AU)

O objetivo do presente estudo foi avaliar o processo de salinização e as alterações dos atributos químicos de um Argissolo cultivado com melão irrigado com água de diferentes concentrações salinas. O experimento foi desenvolvido em campo aberto utilizando o delineamento de blocos casualizados em parcelas subdividas. As parcelas constituíram de níveis de salinidade da água de irrigação, expressa em condutividade elétrica da água (CEa): 0,54; 1,48; 2,02; 3,03 e 3,90 dS m-1 e, as sub-parcelas de cultivares de melão: Sancho e Medellín (Pele de Sapo), Mandacaru (Amarelo), Néctar (Gália) e Sedna (Cantaloupe). Amostras de solos foram coletadas no início e no final do ciclo da cultura para avaliação do processo de salinização e das alterações dos atributos físico-químicos do solo. Os resultados mostraram que a ECse no perfil do solo variou para cada cultivar, sendo as maiores salinidades observadas nos solos cultivados com as cultivares que utilizam uma menor demanda hídrica (Sedna e Néctar). A salinidade do solo foi sempre inferior ao da condutividade elétrica da água de irrigação nos tratamentos com maiores CEa. Os valores de pH do solo apresentaram pequena reação em relação aos valores iniciais. Os valores de porcentagem de sódio trocável foram cerca de duas vezes superiores ao da razão de adsorção de sódio do estrato de saturação. (AU)

Salt-tolerance induced by leaf spraying with H2O2 in sunflower is related to the ion homeostasis balance and reduction of oxidative damage.

Salinity is still one of the main factors that limit the growth and production of crops. However, currently, hydrogen peroxide (H2O2) priming has become a promising technique to alleviate the deleterious effects caused by salt. Therefore, this study aimed to test different leaf spraying strategies with H2O2 for acclimation of sunflower plants to salt stress, identifying the main physiological and biochemical changes involved in this process. The experiment was conducted in a completely randomized design, with four replications. Initially, four concentrations of H2O2 were tested (0.1; 1; 10 and 100 mM) associated with different applications: 1AP - one application (48 h before exposure to NaCl); 2AP - two applications (1AP + one application 7 days after exposure to NaCl) and 3AP - three applications (2AP + one application 14 days after exposure to NaCl), besides this two reference treatments were also added: control (absence of NaCl and absence of H2O2) and salt control (presence of 100 mM of NaCl and absence of H2O2). The experiment was conducted in hydroponic system containing Furlani's nutrient solution. Salt stress reduced the growth of sunflower plants, however, the H2O2 priming through leaf spraying was able to reduce the deleterious effects caused by salt, especially in the 1 mM H2O2 treatment with one application. H2O2 acts as a metabolic signal assisting in the maintenance of ionic and redox homeostasis, and consequently increasing the tolerance of plants to salt stress.

Growth and production of ornamental sunflower irrigated with dilutions of treated domestic sewage / Crescimento e produção de girassol ornamental irrigado com diluições de efluente doméstico tratado

The water and nutritional potential of wastewater has been frequently exploited as an alternative water source for the irrigation of crops, especially in regions affected by the scarcity of water resources. Thus, this study aimed to evaluate growth and production of ornamental sunflower (Helianthus annuus L.) cv. Anão de Jardim irrigated with different dilutions of treated domestic sewage in public-supply water. The experiment was conducted in completely randomized design with five treatments and four replicates, in a greenhouse, in the Experimental Area of the Agricultural Engineering Graduate Program of the Federal University of Recôncavo of Bahia, located in the municipality of Cruz das Almas - BA, Brazil. Treatments started seven days after transplanting of the seedlings and consisted of five dilutions of treated domestic sewage (TDS) in public-supply water (PSW) (100% PSW ­ control; 25% TDS + 75% PSW; 50% TDS + 50% PSW; 75% TDS + 25% PSW and 100% TDS). In the control treatment, plants were fertilized with 100% of the mineral fertilization recommendation, whereas plants in treatments with effluent received 50% of the nitrogen (N) and potassium (K) recommendation. Biometric (plant height, stem diameter, number of leaves, shoot fresh and dry matter and leaf area) and production (capitulum internal and external diameter, capitulum fresh and dry matter, beginning of flowering and full capitulum opening) indicators evaluated at harvest demonstrated that ornamental sunflower plants irrigated with 100% TDS showed similar performance to those irrigated with PSW, which makes it possible to infer on the possibility of replacing PSW by TDS in irrigation, along with the 50% reduction in the recommendation of N and K fertilization, with no damage to the growth and production of ornamental sunflower, cv. Anão de Jardim, thus leading to the saving of good-quality water and fertilizers. KEYWORDS:Helianthus annuus L.. Wastewater. Water resources. INTRODUCTION In agriculture, water is essential for crop development and production. Therefore, in areas where rainfall is scarce, it is of fundamental importance to complement irrigation. In some regions, such as the Northeast semi-arid region, where weather conditions establish a situation of scarcity of water resources due to the low rainfall levels and high evapotranspiration rates, domestic and industrial purposes are the priority in the use of water, which limits the use and expansion of irrigated agriculture. In addition to such limitation, most regions also face sanitary problems, with poor sanitation systems and sewage effluents dumped in watercourses, causing contamination of water bodies and environment. Given this environmental degradation, especially water pollution, many studies have been carried out in Brazil to establish a sustainable management for water resources. Since irrigated agriculture is one of the most water-consuming activities and water resources are becoming increasingly scarce, wastewater utilization in agriculture and studies on defining techniques for the treatment of these waters and their subsequent use have been stimulated (CUBA et al., 2015). The reuse of water in agriculture has increased significantly due to factors such as the increasing difficulty in identifying alternative sources of water for irrigation, the high cost of fertilizers and the treatment systems required before its discharge into receiving bodies, in addition to the guarantee of being used with minimum risks to public health and soil contamination. Therefore, water reuse represents a tool for the sustainability of water resources, applied mainly for non-potable Received: 08/04/19 Accepted: 30/12/19

O potencial hídrico e nutricional da água residuária vem sendo frequentemente explorado como fonte hídrica alternativa para irrigação de culturas, principalmente em regiões acometidas pela escassez de recursos hídricos. Desse modo, o objetivo deste trabalho foi avaliar o crescimento e a produção do girassol ornamental (Helianthuns annuus L.) cv. Anão de Jardim irrigado com diferentes diluições de efluente doméstico tratado em água de abastecimento. O experimento foi conduzido em delineamento experimental inteiramente casualizado com cinco tratamentos e quatro repetições, em casa de vegetação na área experimental do Programa de Pós-Graduação em Engenharia Agrícola, da Universidade Federal do Recôncavo da Bahia, localizada no munícipio de Cruz das Almas (BA). Os tratamentos foram iniciados sete dias após o transplantio das mudas e constituíram-se de cinco diluições de efluente doméstico tratado (EDT) com água de abastecimento (AA) (100% AA ­ testemunha; 25% EDT + 75% AA; 50% EDT + 50% AA; 75% EDT + 25% AA e 100% EDT). No tratamento testemunha as plantas foram adubadas com 100% da recomendação de fertilizante mineral e nos tratamentos com efluente utilizou-se 50% da recomendação de nitrogênio e de potássio. Os indicadores biométricos (altura, diâmetro do caule, número de folhas, massa fresca e seca da parte aérea, área foliar) e de produção (diâmetro interno e externo do capítulo e massa fresca e seca do capítulo, início da floração e abertura total do capítulo) avaliados na colheita mostraram que as plantas de girassol ornamental irrigadas com 100% do efluente apresentaram desempenho semelhante ao das plantas irrigadas com água de abastecimento, o que permite inferir sobre a possibilidade de substituição da água de abastecimento por efluente doméstico tratado para a irrigação juntamente com a redução de 50% da recomendação de adubação com nitrogênio e potássio sem prejuízos ao crescimento e produção das plantas de girassol ornamental cv. Anão de Jardim, resultando assim a economia de água de boa qualidade e de fertilizantes.

Fruit quality of west indian cherry irrigated with saline waters under combinations of nitrogen/potassium fertilization / Qualidade de frutos de aceroleira irrigada com águas salinas sob combinações de adubação nitrogenada / potássica

West Indian cherry stands out among the fruits cultivated for the pharmacological and alimentary importance, but its quality can be affected by irrigation water salinity and fertilization management. In this context, this study aimed to evaluate the effect of irrigation water of different salinities and combinations of nitrogen and potassium fertilization on the physical and physico-chemical quality of bioactive compounds in West Indian cherry fruits. The experiment was carried out in the field, using lysimeters of 60 L, in the Experimental Area of the Centro de Ciências e Tecnologia Agroalimentar (CCTA) of Universidade Federal de Campina Grande (UFCG), Pombal, PB, in a randomized block design, with treatments arranged in a 5 x 4 factorial scheme, referring to five irrigation water salinities (ECw): 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): 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 Indiancherry, with three replicates and one plant per plot consisting of a lysimeter. The cv. Flor Branca grafted on cv. Junco was used in the study. The increase in salinity of irrigation water reduced the size, weight and vitamin C content of the fruits, but, the combinations of N and K fertilization did not affect fruit shape and the content of anthocyanin, carotenoids, pH, titratable acidity, total soluble solids and fruit flavor. Fertilization combinations consisting of C1 and C2 treatments promoted the largest fruit size under irrigation with ECw of up to 1.3 dS m-1 and greater mass accumulation. Fertilization doses above C2 combinations negatively affected fruit quality.

A aceroleira se destaca entre as fruteiras cultivadas pela importância farmacológica e alimentícia de seus frutos, porém sua qualidade pode ser afetada pela salinidade da água de irrigação e o manejo da adubação. Neste sentido, objetivou-se com o trabalho estudar o efeito de diferentes salinidades da água de irrigação e de combinações de adubação nitrogenada e potássica sobre a qualidade física, físico-química e de compostos bioativos em frutos de aceroleira. O experimento foi conduzido em campo, usando lisímetros de 60 L, na Área Experimental do Centro de Ciências e Tecnologia Agroalimentar (CCTA) da Universidade Federal de Campina Grande (UFCG), Pombal, PB, 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 e 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, sendo a qualidade dos frutos avaliada entre 260 e 295 dias após o transplantio. O incremento na salinidade da água de irrigação reduziu o tamanho, o peso e o teor de vitamina C nas acerolas, porém, assim como as combinações de adubação de N e K, não afetaram o formato de frutos e os teores de antocianinas, carotenoides, pH, acidez titulável, sólidos solúveis totais e o sabor dos frutos. As combinações de adubação C1 e C2 proporcionaram o maior tamanho de frutos pela irrigação com CEa de até 1,3 dS m-1 e promoveram maior acúmulo de massa. Doses de fertilização acima da combinação C2 afetaram negativamente a qualidade dos frutos mesmo em plantas irrigadas com água de baixa salinidade.