Cowpea is a nutritionally and economically valuable legume, known for its adaptability to adverse conditions. However, water stress negatively affects its development, requiring technologies to enhance resilience. This study aimed to induce tolerance to water deficit in cowpea through seed priming with polyethylene glycol 6000 (PEG 6000) and silicic acid. A completely randomized experiment was conducted in a phytotron chamber with two water regimes (W50 and W100) and six seed priming treatments, with four replications. Priming consisted of three water potentials induced by PEG 6000 (0 MPa, −0.4 MPa, and −0.8 MPa) and two silicon concentrations (0 and 200 mg L⁻¹). Gas exchange parameters, including photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), intercellular CO₂ concentration (Ci), instantaneous water use efficiency (WUEi), and instantaneous carboxylation efficiency (iCE), were evaluated. Seed priming with PEG 6000 and silicon improved A, WUEi, and iCE under water deficit. Treatments 2 (0 MPa + 200 mg L⁻¹ Si), 3 (−0.4 MPa + 0 mg L⁻¹ Si), and 4 (−0.4 MPa + 200 mg L⁻¹ Si) enhanced gas exchange, suggesting an effective strategy for improving drought tolerance in cowpea and ensuring food security.

Blue light strongly influences plant development, but its interaction with ethylene, a seed conditioning agent for abiotic stress tolerance, is poorly unde

This study investigated whether foliar application of silicon (Si) and methionine (Met) can modulate the biochemical metabolism and growth of cowpea ‘BRS Exuberante’ during water restriction and rehydration cycles, based on the hypothesis that these elicitors could improve physiological recovery after water stress. Considering the above, the experiment was conducted in a completely randomized design, in a 2 × 4 factorial scheme, with four replications. The factors studied were: water stress period and rehydration period. In addition, the following foliar doses of the elicitors were applied: control, 300 mg L-1 of Si, 890 mg L-1 of Met, and the combination of both, 300 mg L-1 of Si + 890 mg L-1 of Met. The results that positively impacted the mitigation of water stress observed in the presence of silicon were more related to growth, although they also reflected improvements in biochemical metabolism. Methionine, on the other hand, was associated with changes in biochemical aspects that benefited growth. In both cases, the improvements that occurred during water restriction were what enabled greater recovery potential after rehydration. Both attenuating agents proved effective in inducing tolerance to certain physiological characteristics. Therefore, their use represents a promising alternative to strengthen the tolerance mechanisms of cowpea, especially by stimulating its ability to recover from stress after rehydration.

ESTERCO OVINO AUMENTA A CAPACIDADE DE RETENÇÃO E MANUTENÇÃO DE ÁGUA NO SOLO DO CARIRI PARAIBANO LUCYELLY DÂMELA ARAÚJO BORBOREMA¹; PATRÍCIA DA SILVA COSTA²; PRISCYLLA MARQUES DE OLIVEIRA VIANA³; YANKA BEATRIZ GONÇALVES BATISTA⁴; MATHEUS CAVALCANTE DA SILVA⁵ E RENER LUCIANO DE SOUZA FERRAZ^{6   2} Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, Rua Aprígio Veloso, n° 882, Bairro Universitário, CEP 58428-830, Campina Grande, Paraíba, Brasil. patriciagroambiental@gmail.com. ³ Departamento de Agroecologia e Agropecuária, Universidade Estadual da Paraíba, Sítio Imbaúba, S/N, Zona Rural, CEP 58117-000, Lagoa Seca, Paraíba, Brasil, pri.marques.o@hotmail.com. ⁴ Unidade Acadêmica de Tecnologia do Desenvolvimento, Universidade Federal de Campina Grande, Rua Luiz Grande, S/N, Bairro Frei Damião, CEP 58540-000, Sumé, Paraíba, Brasil, yankabeariz7@gmail.com. ⁵ Unidade Acadêmica de Tecnologia do Desenvolvimento, Universidade Federal de Campina Grande, Rua Luiz Grande, S/N, Bairro Frei Damião, CEP 58540-000, Sumé, Paraíba, Brasil, matheuscavalcantedasilva.2015@gmail.com. ⁶ Unidade Acadêmica de Tecnologia do Desenvolvimento, Universidade Federal de Campina Grande, Rua Luiz Grande, S/N, Bairro Frei Damião, CEP 58540-000, Sumé, Paraíba, Brasil, ferragroestat@gmail.com.     1 RESUMO   A matéria orgânica do solo contribui para a sustentabilidade dos sistemas agrícolas, pois, influencia os atributos físicos, químicos e biológicos do solo, estabilizando a produtividade dos agroecossistemas. O teor de matéria orgânica no solo beneficia o aumento da capacidade de troca de cátions, assegurando os nutrientes no solo e reduzindo suas perdas por lixiviação. Nesse sentido, objetivou-se avaliar doses de esterco ovino para retenção e manutenção de água no solo na Microrregião do Cariri paraibano. O delineamento utilizado foi o inteiramente casualizado com seis doses de esterco ovino (0, 5, 10, 15, 20 e 25%, m/m) e quatro repetições. Foram realizadas avaliações de pesagem durante seis dias, a cada 24 h, para a determinação da porcentagem de água disponível em relação à massa seca do solo (m/m). Os dados foram submetidos à análise de variância ao nível de 5% de probabilidade de erro e as médias das doses de esterco foram submetidas a regressão polinomial. O esterco ovino aumenta a capacidade de retenção e manutenção da água no solo do Cariri paraibano, sendo uma alternativa para a atenuação dos problemas ocasionados pela perda de água por lixiviação e, por conseguinte, melhorando a capacidade produtiva do solo e vida dos produtores. Keywords: matéria orgânica, nutrientes no solo, status hídrico.     BORBOREMA, L. D. A.; COSTA, P. S.; VIANA, P. M. O.; BATISTA, Y. B. G.; SILVA, M. C.; FERRAZ, R. L. S. SHEEP MANURE INCREASES THE WATER HOLDING AND MAINTENANCE CAPACITY OF SOIL IN THE CARIRI PARAIBANO REGION     2 ABSTRACT   Soil organic matter contributes to the sustainability of agricultural systems, as it influences the physical, chemical and biological attributes of the soil, stabilizing the productivity of agroecosystems. The organic matter content in the soil benefits the increase of the cation exchange capacity, ensuring the nutrients in the soil and reducing its losses due to leaching. In this sense, the objective was to evaluate different doses of sheep manure for retention and maintenance of water in the soil in the Microregion of Cariri, in Paraíba state. The design used was completely randomized with six doses of sheep manure (0, 5, 10, 15, 20 and 25%, w/w) and four replications. Weighing evaluations were carried out for six days, every 24 h, to determine the percentage of available water in relation to the soil dry mass (w/w). Data were subjected to analysis of variance at a 5% probability of error and means of sheep manure doses were submitted to polynomial regression. Sheep manure increases the capacity of retaining and maintaining water in the soil of Cariri, in Paraíba state, being an alternative to alleviate the problems caused by the loss of water through leaching and, therefore, improving the productive capacity of the soil and the life of producers. Keywords: organic matter, soil nutrients, water status.

The relevance of cowpea (Vigna unguiculata (L.) Walp.) in semi-arid regions drives the search for drought tolerance strategies. Our hypothesis was that see

Moringa oleifera Lam. It is a multiple uses plant, whether used as human food (flowers, leaves, fruits and seeds) and animal (forage production), water treatment for human consumption, cosmetics and medicine industry, fuel, paper production. It is considered an exotic tree species that has adapted to the edaphoclimatic conditions of the semiarid region of the Brazilian Northeast, although the occurrence of water deficit reduces growth, limits development and compromises the physiology of the plant. Silicon is a water deficit mitigating agent. The objective of the present study was to evaluate the effect of silicon doses in inducing the tolerance of Moringa oleifera to water stress, on vegetative growth. The study was developed in partnership with the Center for Agricultural and Environmental Sciences of the State University of Paraíba, located in the municipality of Lagoa Seca - PB. The experiment was set up in a randomized block design, in split plots in a 5x5 double factorial scheme, with five irrigation depths (25, 50, 75, 100 and 125% of ETc) and five silicon doses (0, 3, 6 , 9 and 12 g of silicon dioxide per plant), totaling 25 treatments with four replications, with 100 experimental units which consisted of three useful plants. In the plots were the irrigation depths and in the sub-plots were the silicon doses. Irrigation depths exerted a significant influence on all growth variables studied.