Salt stress is abiotic stress that directly affects the gas exchange and redox metabolism of the plants. However, some studies claim that the combination of potassium-phosphorus fertilization may ...increase salt tolerance in plants. In this context, the objective of this study was to evaluate gas exchange and the antioxidant enzyme activity responses to combined potassium-phosphorus fertilization in the tissues of West Indian cherry during the fructification phase, 240 days after application of treatments (DAT) in the second year of brackish water irrigation production. The treatments were distributed in randomized blocks, in a 5 × 4 factorial scheme, with five levels of irrigation water electrical conductivity - (ECw equal to 0.6 - control, 1.4; 2.2; 3.0 or 3.8 dS m
−1
) and four potassium-phosphorus fertilization combinations, 200/120; 170/102; 120/72 or 90/54 g K
2
O/P
2
O
5
plant
−1
per year, with three replicates. Irrigation water salinity impaired the gas exchange, showing a reduction of 47.94, 47.21, and 43.92% in the stomatal conductance, transpiration, and CO
2
assimilation, respectively. In contrast, it increased the antioxidant metabolism, mainly the catalase enzyme activity (+ 67.7%). The average weight of fruits was increased by 85% in the combination of 90/54 under 1.4 dS m
−1
. Although the average number of fruits, in same combination (90/54) was 37% lower compared to high salinities. The threshold water salinity (1.12 dS m
−1
) indicates that West Indian cherry is a salt sensitive crop.
In semiarid regions of Brazil, water and/or soil salinity is one of the limiting factors for sour passion fruit production. Low rainfall rates combined with edaphic conditions (high concentrations of ...soluble salts) intensify deleterious effects on plants. Thus, strategies that minimize the effects of salt stress, e.g., grafting with tolerant species and soil mulching, are extremely important to ensure the expansion of irrigated fruit farming in this region. From this perspective, this study aimed to evaluate the effect of grafting and mulching on the quantum yield, ionic relations, and fruit production of sour passion fruit irrigated with moderately saline water. The experiment was conducted under field conditions in split plots, in a 2 × (2 × 2) factorial arrangement to evaluate the combination of low and moderate salinity water (main plot) with the propagation method (seeds and grafting on P. cincinnata) and without and with plastic mulching (subplots), with four replications and three plants per plot. The ionic relations in passion fruit leaves were increased with the use of rootstocks and plastic mulching under irrigation with moderately saline water. The use of mulching increased the yield of photosystem II in sour passion fruit. The passion fruit plants propagated by seeds had 187.52% more fruits than those grafted onto P. cincinnata. The use of rootstocks with P. cincinnata in sour passion fruit restricted the uptake of Na and Cl but reduced fruit production.
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.
To evaluate the interaction between foliar application of salicylic acid and
Bradyrhizobium
inoculation on the morphophysiology of cowpea under water stress conditions, four genotypes (BRS Rouxinol, ...BRS Marataoã, BRS Aracê and BR 17 Gurguéia) were subjected to five combinations of water availability: 100% replacement of crop evapotranspiration (control); 50% replacement of crop evapotranspiration (water stress); water stress + salicylic acid; water stress +
Bradyrhizobium
inoculation; and water stress + salicylic acid +
Bradyrhizobium
inoculation. The experiment was set up in a 4 × 5 factorial randomized block design, with four replicates and four plants per plot. Water stress negatively affected the leaf water potential, growth, proline contents and antioxidant activity of the cowpea genotypes, and BRS Marataoã was the most sensitive. Under water stress conditions,
Bradyrhizobium
inoculation was efficient for BRS Rouxinol, but was only efficient for BRS Marataoã, BRS Aracê and BR 17 Gurguéia when associated with foliar application of salicylic acid, maintaining their values of leaf water potential, growth, proline content and activities of superoxide dismutase, ascorbate peroxidase, and catalase similar to those of the control treatment.
This study aimed to evaluate the effect of fertilization combinations of nitrogen (N), phosphorus (P), and potassium (K) on the production and quality of West Indian cherry grown under salt stress in ...the second year of production. The study was conducted in a protected environment following a randomized block design with treatments distributed in a 2 × 10 factorial arrangement referring to two levels of electrical conductivity of irrigation water (0.6 and 4.0 dS m−1) and 10 NPK fertilization combinations (80-100-100; 100-100-100; 120-100-100; 140-100-100; 100-80-100; 100-120-100; 100-140-100; 100-100-80; 100-100-120 and 100-100-140% of the recommendation in the second year of production), with three replicates and one plant per lysimeter. Production and post-harvest variables evaluated were: the total fruit weight, total number of fruits, mean fruit weight, the polar and equatorial diameter, total soluble solids, pulp pH, titratable acidity, maturity ratio, vitamin C, reducing sugars, total phenolic compounds, total anthocyanins, and flavonoids. The results indicate that irrigation with water having a salinity of 4.0 dS m−1 negatively affected all production variables. The interaction between the ECw of 0.6 dS m−1 and the 100-80-120 NPK fertilization combination increased the total number of fruits and the total fruit weight of West Indian cherry.
•Silicon glass microparticles (SiMPs) induce tolerance to abiotic stresses.•Seed priming mitigated the effects of water restriction in cowpea plants.•Therefore, plants from seeds subjected to SP ...improve tolerance to water stress.
The northeast region of Brazil presents high variations in solar radiation levels and high air temperatures, impairing the growth and production of cowpea, consequently raising the need for technologies to improve the adaptation of cultivated plants. Therefore, this work aimed to promote the tolerance of cowpea (cultivar BRS Itaim) to water deficit induced by polyethylene glycol 6000 through seed conditioning with silicon glass microparticles. The experiment was performed in the field using a completely randomized 6 × 2 factorial scheme design with four replications. Seed priming (SP) consisted of six combinations of water potential (Ψw) and silicon glass microparticles (SiMPs) (T1: Ψw 0 + 0 SiMPs, T2: Ψw 0 + 200 SiMPs, T3: Ψw -0.4 + 0 SiMPs, T4: Ψw -0.4 + 200 SiMPs, T5: Ψw -0.8 + 0 SiMPs, and T6: Ψw -0.8 + 200 SiMPs) and two water replacement levels: plants with water restriction (50 % of water consumption) and without it (100 % of water consumption). Seed priming with silicon glass microparticles and polyethylene glycol 6000 attenuated the deleterious effects of water restriction in cowpea plants through water status homeostasis, osmotic adjustment, and antioxidant mechanism.
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.
The objective of this study was to evaluate the interaction of nitrogen and phosphorus fertilization and irrigation with saline water on the absolute and relative growth of West Indian cherry plant ...in vegetative phase. The research was carried out in protected environment, using lysimeters filled with clay loam Regolithic Neosol, with low P content. The experiment was set up in randomized block design arranged in a factorial scheme with five levels of irrigation water electrical conductivity (0.6; 1.4; 2.2; 3.0 and 3.8 dS m-1) and four managements of P and N fertilization - P/N (100:100; 140:100; 100:140 and 140:140% P/N) with three replicates and one plant per plot. Seedlings of West Indian cherry, cultivars BRS 366-Jaburu, was cleft-grafted on a local rootstock cultivar, from the Seed Garden of EMBRAPA Tropical Agroindustry. The plants were evaluated for absolute and relative growth of the rootstock and graft. The results showed that 40% increase in nitrogen and/or phosphorus supply can increase growth, chlorophyll content and reduced salt stress damage due to saline water in plants up to ECw = 3.0 dS m-1. The combined increase in nitrogen and phosphorus doses, 140:140% P/N, reduced the deleterious effects of saline stress on growth, chloroplastin pigments and membrane damage of the leaf cells of the West Indian cherry plants.
A strategy using bacilli was adopted aiming to investigate the mitigation of the effects of water deficit in sesame. An experiment was carried out in a greenhouse with 2 sesame cultivars (BRS Seda ...and BRS Anahí) and 4 inoculants (pant001, ESA 13, ESA 402, and ESA 441). On the 30th day of the cycle, irrigation was suspended for eight days, and the plants were subjected to physiological analysis using an infrared gas analyzer (IRGA). On the 8th day of water suspension, leaves were collected for analysis: superoxide dismutase, catalase, ascorbate peroxidase, proline, nitrogen, chlorophyll, and carotenoids. At the end of the crop cycle, data on biomass and vegetative growth characteristics were collected. Data were submitted for variance analysis and comparison of means by the Tukey and Shapiro-Wilk tests. A positive effect of inoculants was observed for all characteristics evaluated, contributing to improvements in plant physiology, induction of biochemical responses, vegetative development, and productivity. ESA 13 established better interaction with the BRS Anahí cultivar and ESA 402 with BRS Seda, with an increase of 49% and 34%, respectively, for the mass of one thousand seeds. Thus, biological indicators are identified regarding the potential of inoculants for application in sesame cultivation.
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