ABSTRACT The interest in the use of wastewater has grown, due to the limitation of good quality water, especially in the semi-arid region. The objective was to analyze the chemical alterations of soil irrigated with wastewater and phosphate fertilization, in the production of seedlings of Moringa oleifera Lam. The experiment was installed in a greenhouse, in the forest nursery of the Experimental Station Prof. Ignácio Salcedo from the National Institute of the Semi-Arid Region – INSA, Campina Grande – Paraíba. A randomized block design was adopted, factorial arrangement 5 x 2, with four replications, with five percentages of treated domestic wastewater, diluted in supply water (25%; 50%; 75%; 100% and treated supply water), associated with two nutritional factors (PA – phosphorus fertilization and SA – without fertilization). At 110 days after conducting the treatments, the following soil characteristics were evaluated: hydrogen potential, electrical conductivity, calcium, magnesium, sodium, phosphorus, potassium, sum of bases, aluminum, hydrogen, sulfate, cation exchange capacity and organic matter. The use of phosphate fertilizer contributed positively to the phosphorus, carbon, organic matter and cation exchange capacity of the soil. The increasing percentiles of wastewater leveraged the sum of bases and the cation exchange capacity, simultaneously promoted the increase in Na+, Al, H+Al contents and in the electrical conductivity of the soil saturation extract.

RESUMO O interesse na utilização de águas residuárias tem crescido, devido a limitação de água de boa qualidade, em destaque para o semiárido. Este trabalho teve por objetivo analisar as alterações químicas do solo irrigado com águas residuárias e da adubação fosfatada, na produção de muda de Moringa oleifera Lam. O experimento foi instalado em estufa, do viveiro florestal da Estação Experimental Prof. Ignácio Salcedo do Instituto Nacional do Semiárido – INSA, Campina Grande – Paraíba. Adotou-se o delineamento de blocos casualizados, arranjo fatorial 5 x 2, com quatro repetições, com cinco percentuais de água residual doméstica tratada, diluída em água de abastecimento (25%; 50%; 75%; 100% e água de abastecimento tratada), associados a dois fatores nutricionais (AF – adubação fosfatada e SA – sem adubação). Aos 110 dias após condução dos tratamentos, avaliaram-se as seguintes características do solo: potencial hidrogeniônico, condutividade elétrica, cálcio, magnésio, sódio, fósforo, potássio, soma de bases, alumínio, hidrogênio, sulfato, capacidade de troca catiônica e matéria orgânica. O uso da adubação fosfatada contribuiu de maneira positiva nos teores de fósforo, carbono, matéria orgânica e capacidade de troca catiônica do solo. Os percentis crescente de água residuária alavancaram a soma de bases e a capacidade de troca catiônica, simultaneamente promoveu o aumento nos teores de Na+, Al, H+Al e na condutividade elétrica do extrato de saturação do solo.

RESUMO: A salinidade tem afetado negativamente o cultivo de hortaliças, sobretudo em regiões semiáridas. Neste sentido, o uso de elicitores que atuem na indução de tolerância ao estresse salino, como ácido salicílico, tem se destacado como uma alternativa promissora. Objetivou-se com esse estudo, avaliar os efeitos da pulverização foliar do ácido salicílico na mitigação do estresse salino na morfofisiologia e produção do pimentão cv. All Big. O estudo foi conduzido em casa de vegetação em Campina Grande - PB, utilizando-se o delineamento inteiramente casualizado, em arranjo fatorial 4 x 4, sendo quatro níveis de condutividade elétrica da água de irrigação (0,8; 1,6; 2,4; e 3,2 dS m-1) e quatro concentrações de ácido salicílico (0; 1,2; 2,4 e 3,6 mM), com três repetições. A aplicação foliar de ácido salicílico na concentração de 1,6 mM atenuou os efeitos do estresse salino nas trocas gasosas, no crescimento, no peso médio de fruto e na produção total por planta, e diminuiu a porcentagem de extravasamento de eletrólitos intercelulares das plantas de pimentão cv. All Big aos 80 dias após o semeio.

ABSTRACT: Salinity has limited conventional vegetable cultivation, especially in semi-arid regions. In this regard, the use of elicitors that act to induce tolerance to salt stress, such as salicylic acid, has emerged as a promising alternative. This study evaluated the effects of foliar spraying with salicylic acid on the mitigation of salt stress on the morphophysiology and production of bell pepper cv. All Big. The study was conducted in a greenhouse in Campina Grande - PB, Brazil, adopting a completely randomized design, in a 4 x 4 factorial arrangement, corresponding to four levels of electrical conductivity of irrigation water (0.8; 1.6; 2.4; and 3.2 dS m-1) and four concentrations of salicylic acid (0; 1.2; 2.4 and 3.6 mM), with three replicates. The foliar application of salicylic acid at a concentration of 1.6 mM attenuated the effects of salt stress in gas exchange, growth, mean fruit weight, and total production per plant, and decreased the percentage of intercellular electrolyte leakage of sweet pepper cv. All Big plants, at 80 days after sowing.

ABSTRACT. Cotton is one of the largest agricultural commodities that generate various sources of foreign exchange and employment worldwide. However, water deficiency is an environmental factor that limits the production of this crop, especially in semi-arid regions. We evaluated pyruvate supplementation to mitigate the effects of water stress on colored cotton. Experiments were conducted in a greenhouse. We studied two forms of pyruvate supplementation (SP1- via seed and foliar and SP2- only via foliar); three conditions of irrigation management of the plants: water restriction in the vegetative phase (VE), flowering (FL), and vegetative and flowering (VE/FL); and additional treatment (total irrigation throughout the crop cycle and without pyruvate supplementation). The experimental design included a randomized block in a 2 × 3 + 1 factorial scheme. The factors resulted in seven treatments with three replications, with a total of 21 experimental units. Gas exchange, enzyme activity, and production of components were evaluated. Water restriction in the vegetative phase does not cause losses in BRS Jade cotton when supplemented with pyruvate. However, in the flowering and vegetative phases plus flowering, it reduces gas exchange and production components and increases the activity of antioxidant enzymes in relation to plants under full irrigation. Supplementation with pyruvate via seed plus foliar (SP1) was better for BRS Jade cotton grown under water restriction.

A fotorreatividade do estado excitado triplete de tioxantona (TX) foi investigada empregando a técnica de fotólise por pulso de laser. O máximo do comprimento de onda de absorção e o tempo de vida para o seu estado excitado triplete são dependetes do solvente. Quando foram utilizados solventes doadores de hidrogênio, foi observado o surgimento de uma nova banda no espectro de absorção para os transientes, com máximo a 410 nm, a qual foi atribuída ao radical cetila derivado da tioxantona. As constantes de velocidade de supressão para o triplete de tioxantona, k q, variaram de (1,7 ± 0,1) × 10(6) L mol-1 s-1 para tolueno a ca. 10(9) L mol-1 s-1 para fenol e seus derivados contendo substituintes poleres, bem como para indol, trietilamina e DABCO.

The photoreactivity of the triplet excited state of thioxanthone (TX) was investigated employing the laser flash photolysis technique. The wavelength for the absorption maximum and the lifetime of the triplet excited state are solvent dependent. When hydrogen donor solvents were employed, a new band at 410 nm was observed in the triplet absorption spectrum, which was attributed to the ketyl radical derived from thioxantone. Quenching rate constants, k q, ranged from (1.7 ± 0.1) × 10(6) L mol-1 s-1 for toluene to ca. 10(9) L mol-1 s-1 for phenol and its derivatives containing polar substituents, as well as for indole, triethylamine and DABCO.