Salicylic acid improves cowpea productivity under water restriction in the field by modulating metabolism.

Introduction: Salicylic acid has shown promise in alleviating water stress in cultivated plants. However, there is a lack of studies confirming its effectiveness in cowpea plants grown in field conditions. Therefore, this research aimed to evaluate the use of salicylic acid as a water stress mitigator in cowpea cultivars under different irrigation depths in field conditions. Methods: Four cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante, and BRS Pajeú) were subjected to different treatments: control (W100: 100% replacement of crop evapotranspiration - ETc), W50 (50% of ETc), W50+SA2 (50% of ETc + 276 mg L-1 of SA), and W50+SA4 (50% of ETc + 552 mg L-1 of SA). The treatments were combined in a 4×4 factorial scheme with three replications, arranged in a randomized block design. Results: Water restriction had a negative impact on the water status, growth, gas exchange, and production of the cultivars while also leading to changes in the antioxidant metabolism and osmolyte concentration. The application of SA enhanced antioxidant activity and the synthesis of osmotic adjusters under stress conditions. The most effective concentration was 276 mg L-1 in stage R2 and 552 mg L-1 in stage V7, respectively. The BRS Pujante cultivar showed increased productivity under water restriction with SA application, while the BRS Tapaihum was the most tolerant among the cultivars studied. Discussion: In summary, our findings underscore the importance of using SA to mitigate the effects of water restriction on cowpea cultivation. These discoveries are crucial for the sustainability of cowpea production in regions susceptible to drought, which can contribute to food security. We further add that the adoption of new agricultural practices can enhance the resilience and productivity of cowpea as an essential and sustainable food source for vulnerable populations in various parts of the world.

Modulation of Drought-Induced Stress in Cowpea Genotypes Using Exogenous Salicylic Acid.

Plant endogenous mechanisms are not always sufficient enough to mitigate drought stress, therefore, the exogenous application of elicitors, such as salicylic acid, is necessary. In this study, we assessed the mitigating action of salicylic acid (SA) in cowpea genotypes under drought conditions. An experiment was conducted with two cowpea genotypes and six treatments of drought stress and salicylic acid (T1 = Control, T2 = drought stress (stress), T3 = stress + 0.1 mM of SA, T4 = stress + 0.5 mM of SA, T5 = stress + 1.0 mM of SA, and T6 = stress + 2.0 mM of SA). Plants were evaluated in areas of leaf area, stomatal conductance, photosynthesis, proline content, the activity of antioxidant enzymes, and dry grain production. Drought stress reduces the leaf area, stomatal conductance, photosynthesis, and, consequently, the production of both cowpea genotypes. The growth and production of the BRS Paraguaçu genotype outcompetes the Pingo de Ouro-1-2 genotype, regardless of the stress conditions. The exogenous application of 0.5 mM salicylic acid to cowpea leaves increases SOD activity, decreases CAT activity, and improves the production of both genotypes. The application of 0.5 mM of salicylic acid mitigates drought stress in the cowpea genotype, and the BRS Paraguaçu genotype is more tolerant to drought stress.

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.

Allelopathy of Ricinus communis and light spectrum variation decrease emergence and growth of Cyperus rotundus

Weeds negatively influence agricultural production. However, those losses depend on weed specie, its time of emergence, and period of interference on agricultural crops. Synthetic herbicides are commonly used to control these plants species; however, they may cause damage to the environment, human beings and animals health, and this problem justify the need to develop alternative bioherbicides. To evaluate the allelopathic potential of Ricinus communis (Castor bean) and light spectrum variation on the emergence and growth of Cyperus rotundus L., a trial was carried out in a protected environment with 15% of brightness reduction at the Center for Agricultural and Environmental Sciences at the Paraíba State University. Four aqueous extract concentrations of R. communis leaves were tested (0, 5, 10, and 15%) and four light spectrums variations (white, purple, blue, and red lights). Variables such as emergence, length, dry matter accumulation and growth rates of shoots and root of C. rotundus seedlings were assessed. Data were analyzed by normality test, analysis of variance, polynomial regression, and averages test. Soot and root emergence, length, and dry matter accumulation of C. rotundus seedlings were reduced due to the allelopathy caused by R. communis aqueous extract leaves (15% concentration) and under purple or red light spectrum radiation.

Seed Priming with Glass Waste Microparticles and Red Light Irradiation Mitigates Thermal and Water Stresses in Seedlings of Moringa oleifera.

The association between population increase and the exploitation of natural resources and climate change influences the demand for food, especially in semi-arid regions, highlighting the need for technologies that could provide cultivated species with better adaptation to agroecosystems. Additionally, developing cultivation technologies that employ waste materials is highly desirable for sustainable development. From this perspective, this study aimed to evaluate whether seed priming with glass waste microparticles used as a silicon source under red light irradiation mitigates the effects of thermal and water stress on seedlings of Moringa oleifera. The experimental design was set up in randomized blocks using a 2 × 2 × 2 factorial arrangement consisting of seed priming (NSP-no seed priming, and SPSi-seed priming with glass microparticles under red light irradiation), soil water replenishment (W50-50%, and W100-100% of crop evapotranspiration-ETc), and temperature change (TC30°-30 °C day/25 °C night and TC40°-40 °C day/35 °C night). Seed priming with glass microparticles under red light irradiation mitigated the effects of thermal and water stress on seedlings of Moringa oleifera seedlings through the homeostasis of gas exchange, leaf water status, osmotic adjustment, and the antioxidant mechanism.

Desenvolvimento e produção de ecótipos de feijoeiro cultivados na época das águas sob irrigação suplementar / Development and production of common bean ecotypes grown in the rainy season under supplementary irrigation

O cultivo do feijoeiro, Phaseolus vulgaris L., possui grande importância para o Brasil, sobretudo no âmbito econômico e social. Assim, a utilização de ecótipos de feijoeiro promissores associada à otimização dos recursos hídricos configura importante estratégia para a agricultura sustentável em regiões semiáridas. Objetivou-se com este trabalho avaliar o comportamento de ecótipos de feijoeiro cultivados na época das águas com irrigação suplementar. O experimento foi no campus Experimental de Ecofisiologia Vegetal da Universidade Estadual da Paraíba, situada na microrregião de Catolé do Rocha, PB. Utilizou-se o delineamento experimental em blocos casualizados em fatorial 3x4, sendo três ecótipos de feijoeiro (Eco1= G2227, Eco2= BRA 130583 CIAT G6490 e Eco3= BAT 477) e quatro lâminas de irrigação suplementar com 50; 75; 100 e 125% da evapotranspiração de referência (ETo), em três repetições. As variáveis analisadas foram: percentagem e índice de velocidade de emergência, comprimento da haste principal, taxa de crescimento relativo, número de vagens por planta, número de grãos por vagem, massa de 100 grãos, fitomassa da parte aérea e eficiência fotossintética. Os ecótipos de feijoeiro analisados divergem entre si quanto aos aspectos de germinação, crescimento, componentes da produção (NGV e FMA) e eficiência fotossintética. O ecótipo 1 apresenta melhor desempenho quanto aos componentes da produção observados nas condições de Semiárido.

The cultivation of common bean Phaseolus vulgaris L. has great importance for Brazil, especially in the economic and social sector. Thus, the use of promising bean ecotypes associated with optimization of water resources sets an important strategy for sustainable agriculture in semiarid regions. This study was developed in order to evaluate the behavior of common bean ecotypes grown in the rainy season with supplementary irrigation. The experiment was carried out at campus Experimental Plant Ecophysiology at the State University of Paraiba, located in the microregion of Catolé do Rocha - PB. A randomized block experimental design in factorial 3x4 was used, with three common bean ecotypes (Eco1 = G2227, Eco2 BRA = 130583 CIAT G6490 and Eco3 BAT = 477) and four levels of supplementary irrigation (50, 75, 100 and 125% of reference evapotranspiration, ETo) in three replications. The variables analyzed were: percentage and emergence speed index, main branch length, growth rate relative crop, number of pods per plant, number of grains per pod, weight of 100 grains, shoots dry matter and photosynthetic efficiency. The bean ecotypes analyzed were different in aspects of germination, growth, yield components (NVG e FMA) and photosynthetic efficiency. The ecotype 1 shows better performance on the yield components observed in the semiarid conditions.