RESUMO

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.

RESUMO

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.

RESUMO

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.

RESUMO

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.

RESUMO

The objective of this study was to evaluate chloroplast pigments and photochemical efficiency of West Indian cherry cv. BRS 366 Jaburu as a function of irrigation water salinity and potassium-phosphorus fertilization combinations in the second year of cultivation. The experiment was carried out in a protected environment in Campina Grande, Brazil. Treatments were distributed in randomized blocks, in a 5 × 4 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four combinations of potassium-phosphorus fertilization (100/100, 85/85, 60/60 and 45/45% of the K2O/P2O5 recommendation for the second year of cultivation 200 g of K2O and 120 g of P2O5 per plant per year) with three replicates. Irrigation with saline waters hampered the biosynthesis of chloroplast pigments and the photochemical efficiency of West Indian cherry cv. BRS 366 Jaburu in the second year of cultivation. Water salinity from 2.6 dS m-1 reduced the maximum fluorescence, variable fluorescence, and quantum efficiency of photosystem II of West Indian cherry plants cv. BRS 366 Jaburu. Fertilization with 60/60 and 85/85% of the K2O/P2O5 recommendation promotes an increase in the synthesis of chlorophylls a and b, respectively, in the first and second production cycles of the second year of cultivation. Supply of 85/85% of the K2O/P2O5

Objetivou-se com esta pesquisa avaliar os pigmentos cloroplastídicos e a eficiência fotoquímica da aceroleira cv. BRS 366 Jaburu em função da salinidade da água de irrigação e combinações de adubação com potássio-fósforo no segundo ano de cultivo. A pesquisa foi realizada em ambiente protegido, em Campina Grande-PB. Os tratamentos foram distribuídos em blocos casualizados, em esquema fatorial 5 x 4, 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 combinações de adubação com potássio-fósforo (100/100; 85/85; 60/60 e 45/45% de K2O/ P2O5, da recomendação para o segundo ano de cultivo) com três repetições. A combinação de 100/100% correspondeu a 200 g de K2O e 120 g de P2O5 por planta por ano). A irrigação com águas salinas prejudicou a biossíntese de pigmentos cloroplastídicos e a eficiência fotoquímica da aceroleira cv. BRS 366 Jaburu no segundo ano de cultivo. A salinidade da água a partir de 2,6 dS m-1 diminuiu a fluorescência máxima, variável e eficiência quântica do fotossistema II das plantas de aceroleira cv. BRS 366 Jaburu. A adubação com 60/60 e 85/85% da recomendação de K2O/P2O5 promovem aumento na síntese de clorofila a e b de acerola, respectivamente, no primeiro e segundo ciclos produtivos do segundo ano de cultivo. O fornecimento de 85/85% da recomendação de K2O/P2O5 promoveu aumento na florescência máxima e variável nas plantas submetidas a salinidade da água de 0,6; 2,2 e 3,8 dS m-1 no segundo ciclo e reduziu a fluorescência inicial independentemente do nível salino no primeiro e segundo ciclo produtivo da acerola.

Assuntos

RESUMO

This study was conducted to evaluate the gas exchange, growth, and quality of passion fruit cultivars under irrigation with waters of different salinity levels. The experiment was conducted in a greenhouse, in Pombal-PB, Brazil, using a randomized block design in a 5 ? 2 factorial arrangement, with five levels of electrical conductivity of irrigation water (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1) and two passion fruit cultivars (BRS Sol do Cerrado and Guinezinho), with three plants per plot and four replicates. The reduction in transpiration, intercellular CO2 concentration and CO2 assimilation rate in passion fruit plants grown with saline water was related to factors of stomatal and non-stomatal origin. Gas exchange and growth of passion fruit cultivars were negatively affected by water salinity from 0.3 dS m-1 at 75 days after sowing. Despite the reduction in the growth of the passion fruit cultivars, irrigation with water of up to 3.5 dS m-1 could be used to obtain seedlings with acceptable quality. Based on the relative yield of total dry phytomass, the passion fruit cultivars BRS Sol do Cerrado and Guinezinho were classified as moderately sensitive to water salinity during the seedling phase.

Desenvolveu-se este trabalho com o objetivo de avaliar as trocas gasosas, o crescimento e a qualidade de cultivares de maracujazeiro sob irrigação com águas de diferentes níveis salinos. O experimento foi conduzido em casa de vegetação, em Pombal-PB, utilizando-se o delineamento de blocos casualizados em arranjo fatorial 5 × 2, sendo cinco níveis de condutividade elétrica da água de irrigação (0,3; 1,1; 1,9; 2,7 e 3,5 dS m-1) e duas cultivares de maracujazeiro (BRS Sol do Cerrado e Guinezinho), com três plantas por parcela e quatro repetições. A redução na transpiração, concentração intercelular de CO2 e taxa de assimilação de CO2 nas plantas de maracujazeiro cultivadas com águas salinas está relacionado a fatores de origem estomáticos e não estomáticos. As trocas gasosas e o crescimento das cultivares de maracujazeiro foram afetados de forma negativa pela salinidade da água a partir de 0,3 dS m-1, aos 75 dias após o semeio. Apesar da redução no crescimento nas cultivares de maracujazeiro, a irrigação com água de até 3,5 dS m-1 pode ser utilizada para obtenção de mudas com qualidade aceitável. Com base no rendimento relativo de fitomassa seca total, as cultivares de maracujazeiro BRS Sol do Cerrado e Guinezinho foram classificados como moderadamente sensível a salinidade da água na fase de formação de mudas.

Assuntos

RESUMO

This study was conducted to evaluate the gas exchange, growth, and quality of passion fruit cultivars under irrigation with waters of different salinity levels. The experiment was conducted in a greenhouse, in Pombal-PB, Brazil, using a randomized block design in a 5 ? 2 factorial arrangement, with five levels of electrical conductivity of irrigation water (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1) and two passion fruit cultivars (BRS Sol do Cerrado and Guinezinho), with three plants per plot and four replicates. The reduction in transpiration, intercellular CO2 concentration and CO2 assimilation rate in passion fruit plants grown with saline water was related to factors of stomatal and non-stomatal origin. Gas exchange and growth of passion fruit cultivars were negatively affected by water salinity from 0.3 dS m-1 at 75 days after sowing. Despite the reduction in the growth of the passion fruit cultivars, irrigation with water of up to 3.5 dS m-1 could be used to obtain seedlings with acceptable quality. Based on the relative yield of total dry phytomass, the passion fruit cultivars BRS Sol do Cerrado and Guinezinho were classified as moderately sensitive to water salinity during the seedling phase.(AU)

Desenvolveu-se este trabalho com o objetivo de avaliar as trocas gasosas, o crescimento e a qualidade de cultivares de maracujazeiro sob irrigação com águas de diferentes níveis salinos. O experimento foi conduzido em casa de vegetação, em Pombal-PB, utilizando-se o delineamento de blocos casualizados em arranjo fatorial 5 × 2, sendo cinco níveis de condutividade elétrica da água de irrigação (0,3; 1,1; 1,9; 2,7 e 3,5 dS m-1) e duas cultivares de maracujazeiro (BRS Sol do Cerrado e Guinezinho), com três plantas por parcela e quatro repetições. A redução na transpiração, concentração intercelular de CO2 e taxa de assimilação de CO2 nas plantas de maracujazeiro cultivadas com águas salinas está relacionado a fatores de origem estomáticos e não estomáticos. As trocas gasosas e o crescimento das cultivares de maracujazeiro foram afetados de forma negativa pela salinidade da água a partir de 0,3 dS m-1, aos 75 dias após o semeio. Apesar da redução no crescimento nas cultivares de maracujazeiro, a irrigação com água de até 3,5 dS m-1 pode ser utilizada para obtenção de mudas com qualidade aceitável. Com base no rendimento relativo de fitomassa seca total, as cultivares de maracujazeiro BRS Sol do Cerrado e Guinezinho foram classificados como moderadamente sensível a salinidade da água na fase de formação de mudas.(AU)

Assuntos

RESUMO

The objective of this study was to evaluate chloroplast pigments and photochemical efficiency of West Indian cherry cv. BRS 366 Jaburu as a function of irrigation water salinity and potassium-phosphorus fertilization combinations in the second year of cultivation. The experiment was carried out in a protected environment in Campina Grande, Brazil. Treatments were distributed in randomized blocks, in a 5 × 4 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four combinations of potassium-phosphorus fertilization (100/100, 85/85, 60/60 and 45/45% of the K2O/P2O5 recommendation for the second year of cultivation 200 g of K2O and 120 g of P2O5 per plant per year) with three replicates. Irrigation with saline waters hampered the biosynthesis of chloroplast pigments and the photochemical efficiency of West Indian cherry cv. BRS 366 Jaburu in the second year of cultivation. Water salinity from 2.6 dS m-1 reduced the maximum fluorescence, variable fluorescence, and quantum efficiency of photosystem II of West Indian cherry plants cv. BRS 366 Jaburu. Fertilization with 60/60 and 85/85% of the K2O/P2O5 recommendation promotes an increase in the synthesis of chlorophylls a and b, respectively, in the first and second production cycles of the second year of cultivation. Supply of 85/85% of the K2O/P2O5(AU)

Objetivou-se com esta pesquisa avaliar os pigmentos cloroplastídicos e a eficiência fotoquímica da aceroleira cv. BRS 366 Jaburu em função da salinidade da água de irrigação e combinações de adubação com potássio-fósforo no segundo ano de cultivo. A pesquisa foi realizada em ambiente protegido, em Campina Grande-PB. Os tratamentos foram distribuídos em blocos casualizados, em esquema fatorial 5 x 4, 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 combinações de adubação com potássio-fósforo (100/100; 85/85; 60/60 e 45/45% de K2O/ P2O5, da recomendação para o segundo ano de cultivo) com três repetições. A combinação de 100/100% correspondeu a 200 g de K2O e 120 g de P2O5 por planta por ano). A irrigação com águas salinas prejudicou a biossíntese de pigmentos cloroplastídicos e a eficiência fotoquímica da aceroleira cv. BRS 366 Jaburu no segundo ano de cultivo. A salinidade da água a partir de 2,6 dS m-1 diminuiu a fluorescência máxima, variável e eficiência quântica do fotossistema II das plantas de aceroleira cv. BRS 366 Jaburu. A adubação com 60/60 e 85/85% da recomendação de K2O/P2O5 promovem aumento na síntese de clorofila a e b de acerola, respectivamente, no primeiro e segundo ciclos produtivos do segundo ano de cultivo. O fornecimento de 85/85% da recomendação de K2O/P2O5 promoveu aumento na florescência máxima e variável nas plantas submetidas a salinidade da água de 0,6; 2,2 e 3,8 dS m-1 no segundo ciclo e reduziu a fluorescência inicial independentemente do nível salino no primeiro e segundo ciclo produtivo da acerola.(AU)

Assuntos

RESUMO

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.

Assuntos

RESUMO

Excess salts in water and/or soil are a critical factor that adversely affects the physiology and growth, besides limiting the production of crops in the semiarid region of Northeast Brazil. One way to reduce the effect of salt stress on plants is by using silicon (Si) fertilization. In this context, the objective of this study was to evaluate the gas exchange, growth, and production of okra cv. Valença as a function of irrigation with saline water and Si doses. The experiment was conducted in a greenhouse in the municipality of Pombal - PB, Brazil. The experimental design adopted was randomized blocks in a 5 × 2 factorial scheme corresponding to five levels of electrical conductivity of water ECw (0.3, 1.0, 1.7,2.4, and 3.1 dS m-¹) and two doses of Si fertilization (100 and 200 g of Si per plant), with four replicates. Salt stress increased the intercellular concentration of CO2 in the substomatal chamber and reduced the CO2 assimilation rate, instantaneous carboxylation efficiency, growth, and production of okra plants. Intrinsic water use efficiency and average weights of okra fruits were not influenced by irrigation with saline water and Si doses. The supply of 200 g Si per plant reduced the deleterious effect of salt stress on stomatal conductance and leaf area of okra, at 45 days after sowing but did not increase production.

O excesso de sais na água e/ou no solo é um fator crítico que afeta adversamente a fisiologia, o crescimento e limita a produção dos cultivos no semiárido do Nordeste brasileiro. Uma forma de reduzir o efeito do estresse salino sobre as plantas é o uso da adubação com silício. Neste contexto, objetivou-se avaliar as trocas gasosas, o crescimento e a produção do quiabeiro cv. Valença em função da irrigação com águas salinas e doses de silício. O experimento foi conduzido em casa-de-vegetação no município de Pombal-PB. Adotou-se o delineamento experimental de blocos casualizados, em esquema fatorial 5 x 2, sendo cinco níveis de condutividade elétrica da água – CEa (0,3; 1,0; 1,7; 2,4 e 3,1 dS m-¹) e duas doses de adubação silicatada (100 e 200 g de Si planta-¹) com quatro repetições. O estresse salino aumentou a concentração intercelular de CO2 na câmera subestomática e reduziu a taxa de assimilação de CO2, a eficiência instantânea de carboxilação, o crescimento e a produção das plantas de quiabeiro.A eficiência intrínseca no uso da água e o peso médio de frutos do quiabeiro não foram influenciados pela irrigação com águas salinas e doses de silício. O fornecimento de 200 g planta-¹ de silício diminuiu o efeito deletério do estresse salino sobre a condutância estomática e a área foliar de quiabeiro, aos 45 dias após a semeadura, no entanto, não aumentou produção da cultura.

Assuntos