Water status, cell integrity, and growth of cowpea plants under water restriction and salicylic acid¹

Status hídrico, integridade celular e crescimento de feijão-caupi sob restrição hídrica e ácido salicílico

ABSTRACT

The effects of water restriction on cowpea can be reversed by the use of eliciting substances such as salicylic acid (SA). Thus, the objective was to evaluate the water status, cellular integrity and growth of cowpea cultivars under water restriction and spraying with salicylic acid in the field. Four cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante and BRS Pajeu) were subjected to two irrigation levels (water restriction with 50% replacement of water lost through crop evapotranspiration - ETc and control with 100% replacement of ETc) and three concentrations of SA (0, 276 and 552 mg L^-1 of SA), combined in a 4 × 2 × 3 factorial scheme, with three replicates, arranged in a randomized block design. Relative leaf water content (RWC), intracellular electrolyte leakage (IEL), total fresh mass (TFM) and shoot relative growth rate (SRGR) were evaluated at phenological stages V7 and R2. Water restriction reduced RWC, TFM and SRGR and increased IEL, while spraying with 276 mg L^-1 of SA reduced IEL and increased RWC, TFM and SRGR of cowpea cultivars under water restriction, responses that vary according to the cultivar and phenological stage. The cultivar BRS Novaera was more responsive to the application of SA at the V7 stage.

Key words:
Vigna unguiculata L.; drought stress; genotypic plasticity; phytohormone attenuation

HIGHLIGHTS:

Water restriction affects the integrity of membranes and reduces cowpea growth.

Salicylic acid, at 276 mg L^-1, reverses the effects of water restriction in cowpea.

Cultivar and phenological stage influence the reversal of the negative effects of water restriction by salicylic acid.

RESUMO

Os efeitos da restrição hídrica no feijão-caupi podem ser revertidos pelo uso de substâncias elicitoras, tais como o ácido salicílico (AS). Desta forma, objetivou-se avaliar o status hídrico, a integridade celular e o crescimento de cultivares de feijão-caupi sob restrição hídrica e pulverização com ácido salicílico em campo. Quatro cultivares de feijão-caupi (BRS Novaera, BRS Tapaihum, BRS Pujante e BRS Pajeu) foram submetidas a duas lâminas de irrigação (restrição hídrica com 50% de reposição da água perdida por evapotranspiração da cultura - ETc e controle com 100% de reposição da ETc) e três concentrações de AS (0, 276 e 552 mg L^-1 de AS), combinados em esquema fatorial 4 × 2 × 3, com três repetições, dispostos em delineamento de blocos casualizados. O conteúdo relativo de água na folha (CRA), vazamento de eletrólitos intracelulares (VE), massa da matéria fresca total (MFT) e taxa de crescimento relativo da parte aérea (TCRA) foram avaliados nos estádios fenológicos V7 e R2. A restrição hídrica reduziu CRA, MFT e TCRA e aumentou VE, enquanto a pulverização com 276 mg L^-1 de AS reduziu VE e aumentou CRA, MFT e TCRA das cultivares de feijão-caupi sob restrição hídrica, respostas que variam de acordo com a cultivar e estádio fenológico. A cultivar BRS Novaera mostrou-se mais responsiva a aplicação de AS no estádio V7.

Palavras-chave:
Vigna unguiculata L.; estresse por seca; plasticidade genotípica; atenuação com fitormônio

Introduction

Cowpea (Vigna unguiculata L.) Walp. has variable water requirements throughout its phenological phases. It requires small amounts of water during germination, has high demand during flowering and pod growth, and has reduced water needs when the grains mature (Parraga et al., 2020).

Santos et al. (2020) reported that water deficiency right after sowing can directly affect germination, limiting the initial growth, and vigor of cowpea seedlings. Lack of water in the vegetative phase can stop or delay plant growth (Silva et al., 2019; Ayala et al., 2020). Although cowpea is considered a species that can withstand drought conditions (Ezin et al., 2021), its cultivation and production are limited in regions with irregular rainfall distribution, such as the Brazilian Northeast (Silva et al., 2020).

Salicylic acid (SA) has been shown to be an interesting alternative to mitigate the effects of water restriction in several vegetables, mainly because it acts in growth regulation (Oliveira et al., 2023). Its use allows increases in the relative water content of basil (Carvalho et al., 2020), and reduction of electrolyte leakage in barley (Abdelaal et al., 2020) under water deficit. In maize plants (Zea mays L.), Shemi et al. (2021) highlight that SA reverses the effects of water restriction on total fresh mass, while Andrade et al. (2020) highlight improvements in the architecture of cowpea plants with the use of this substance, but its effects have varied according to the cultivar.

Genetic improvement programs for cowpea have often introduced new cultivars recommended for cultivation in different agroecosystems. However, there is still a lack of studies evaluating water restriction and the use of salicylic acid (SA) to mitigate stress in this species. The objective of this study was to assess the water status, cellular integrity, and growth of cowpea cultivars under water restriction and foliar spraying with salicylic acid under field conditions.

Material and Methods

The experiment was carried out in an agricultural area owned by the Centro de Ciências Agrárias e Ambientais (CCAA) of the Universidade Estadual da Paraíba (UEPB), in Lagoa Seca, PB, Brazil, from January to April 2020. The location’s coordinates are latitude 7º 09’ 22.6” S, longitude 35º 52’ 8.46” W, and altitude of 634 m. The meteorological conditions, obtained through the meteorological station model HOBO RX3000 - CELL-3G installed close to the experimental area, are depicted in Figure 1.

Figure 1
Data on T avg. - average air temperature, rainfall accumulated every six days, and U avg. - relative air humidity during the experimental period

Four cowpea cultivars, two irrigation depths, and three concentrations of salicylic acid (SA) were evaluated in a randomized block design, arranged in a 4 × 2 × 3 factorial scheme with three replicates, resulting in 72 experimental units measuring 1.10 m wide and 2.0 m long (area of 2.2 m²), with five supervision rows and 10 plants per row, totaling 50 plants, 24 (8 from each of the 3 central rows) used for assessments.

The cultivars used were BRS Novaera, BRS Tapaihum, BRS Pajeu, and BRS Pujante. The irrigation depths included plants subjected to water restriction (replacing 50% of water lost through crop evapotranspiration, ETc) and plants without water restriction (replacing 100% of ETc). Salicylic acid (SA) was applied to plants at concentrations of zero (control - without SA), 276 and 552 mg L^-1 of SA (C₇H₆O₃, molecular weight of 138.12 g mol^-1) from Sigma-Aldrich, adapted from Araújo et al. (2018) and applied as shown in Figure 2.

Figure 2
A simplified schematic illustration of a split-plot block diagram showing the distribution of cultivars and salicylic acid concentrations within two irrigation depths.

Any seeds with physical damage, biological damage, or poor formation were removed before the experiment. The selected seeds were then treated with fungicide Captan^®, with 480 g L^-1 a.i. Captana. The fungicide was applied to the seeds using 0.22 g 100 g^-1 of seeds, rotated for 5 minutes. After that, the treated seeds were stored for 24 hours at room temperature and low light. Following the treatment, one seed was sown manually per hole, at a depth of 3 cm. The holes were spaced 10 cm apart, and the planting rows were spaced 50 cm apart (Rocha et al., 2019).

The soil in the experimental area has the following characteristics: 86.04% sand, 12.05% silt, 1.91% clay, apparent density of 1.62 g cm^-3, particle density of 2.69 g cm^-3, 39.77% porosity, 2.31 cmol_c dm^-3 calcium, 2.30 cmol_c dm^-3 magnesium, 0.05 cmol_c dm^-3 sodium, 0.27 cmol_c dm^-3 potassium, 4.93 cmol_c dm^-3 sulfur, 0.89 cmol_c dm^-3 hydrogen, 0.00 cmol_c dm^-3 aluminum, 1.10% organic matter, and pH of 6.62, determined according to Teixeira et al., (2017).

Irrigation was applied daily from 7:00 to 8:00 AM, based on the crop’s water requirements (ETc). A drip system was used, consisting of drip tapes with wall thickness of 0.2 mm, and internal diameter of 16 mm. The system had pressure-compensating emitters with flow rate of 1.6 L h^-1, spaced every 10 cm. Water replacement was calculated using the Penman-Monteith method (FAO) (Allen et al., 1998), which relied on climate data from an agrometeorological station located near the experimental area (7° 09’ 26.1” S, 35° 52’ 16.9” W).

At 18 and 36 days after sowing (DAS) (phenological stages V3 and V9, respectively), from 7:30 to 9:00 AM, 20 mL of salicylic acid were sprayed on each plant using a 20 L sprayer with a 40 PSi pressure. Wil Fix adhesive spreader (0.05% of the total volume of each solution) was added to the solutions for each treatment, in order to avoid evaporation during and after spraying, which was directed to both the upper and lower surfaces of the leaves. On the day after the first spraying (19 DAS), water restrictions were implemented by adjusting the irrigation depths.

Top dressing was applied using DripSol MAP (Monoammonium Phosphate with 12% N and 65% P₂O₅) at 10 and 18 DAS through fertigation. A total of 390 g of this fertilizer was applied in 10 L of water for each fertilization event using a venturi-type fertilizer injector (Oliveira et al., 2023). At 37 DAS, 10 mL of the insecticide Benevia^® (100 g L^-1 a.i. Cyantraniliprole) was sprayed on the leaves in 20 L of water along with 4 mL of an adhesive spreader. Additionally, at 18 DAS, the interrows of the plots were covered with a 5 cm layer of dry matter from weeds that grew in the experimental area (Maia Júnior et al., 2019). Manual weed control was performed throughout the experiment.

At the phenological stage V7 (29 DAS) (11 days after SA application), three plants were collected from each experimental plot and weighed on an analytical scale (e = 0.0001 g) to determine total fresh mass (TFM) (g per plant). The plants were then stored in a refrigerated container and transported to the Ecophysiology of Cultivated Plants Laboratory (ECOLAB) at UEPB in Campina Grande, PB, Brazil (07° 13’ 50’’ S latitude, 35° 52’ 52’’ W longitude, and 551 m altitude) for evaluation of relative leaf water content (RWC) (%) using the method described by Smart & Bingham (1974), and intracellular electrolyte leakage (IEL) (%) according to Campos & Thi (1997).

The evaluations were repeated when the plants reached the R2 phenological stage (51 DAS). From the TFM data obtained at stages V7 and R2, shoot relative growth rate (SRGR) (g g^-1 per day) was calculated following the method described by Ferraz et al. (2017).

The data obtained were subjected to the Shapiro-Wilk normality test (Shapiro & Wilk, 1965), and given the normality assumptions, they were subjected to analysis of variance at p ≤ 0.05. If there was a significant interaction, this was followed by t-test (p ≤ 0.05) for comparing means of irrigation depths, and Tukey test for multiple comparisons of means (Tukey, p ≤ 0.05), for cultivars and SA concentrations, within each irrigation depth, using the computer software Sisvar 5.6 (Ferreira, 2019).

Results and Discussion

At the V7 phenological stage, there were significant reductions of 9.84 and 18.31% in the relative leaf water content (RWC) of the cultivars BRS Pujante and BRS Pajeu, respectively, when subjected to water restriction and no spraying of salicylic acid (SA), compared to plants grown with 100% replacement of ETc. However, when these cultivars were sprayed with 276 and 552 mg L^-1 of SA under 50% ETc, there was no difference in RWC compared to those cultivated with 100% ETc. Under stress conditions, plants of the BRS Pajeu cultivar sprayed with SA concentrations showed significantly higher RWC (18.5 and 19% respectively) compared to those that did not receive this treatment under the same water condition (Figure 3A).

Figure 3
Relative water content in the leaves of cowpea cultivars at phenological stages V7 (A) and R2 (B) subjected to irrigation depths and salicylic acid concentrations

At this phenological stage, increases of 11.7 and 13% in RWC were also found in BRS Tapaihum plants with the spraying of 276 and 552 mg L^-1 of SA, respectively, under the 100% ETc depth, compared to the control (without SA). However, under this same water condition, the cultivars BRS Novaera and BRS Pajeu showed a 19% reduction in RWC under sprays of 276 and 552 mg L^-1 of SA, respectively, compared to plants not treated with this acid and at the same irrigation level (Figure 3A).

Furthermore, at this phenological stage, it is observed that under full irrigation (W100) and absence of SA, the BRS Pajeu cultivar has a significantly higher RWC compared to the BRS Tapaihum cultivar, while under this same water condition, a negative performance of the cultivar was observed. BRS Novaera under application of SA has lower values ​​than the other varieties with both concentrations of SA. Nevertheless, it is noteworthy that under stress conditions, at this phenological stage, the cultivars do not show any difference in RWC levels, regardless of the treatment evaluated (Figure 3A).

At the R2 phenological stage, there was no effect of the treatments on the RWC of the BRS Novaera and BRS Tapaihum cultivars. However, the cultivars BRS Pujante and BRS Pajeu showed significant decreases of 28 and 11.5% in RWC under conditions of water restriction and in the absence of SA. This same behavior was observed in plants sprayed with 276 mg L^-1 of SA in the cultivar BRS Pujante and in the cultivar BRS Pajeu subjected to spraying with 552 mg L^-1 of SA, resulting in RWC values being reduced by 10 and 21%, respectively (Figure 3B). At this phenological stage, it is possible to notice a greater sensitivity of the BRS Pujante cultivar to water restriction, since plants subjected to the W50 + 0 mg L^-1 SA treatment, in this cultivar, show significantly lower RWC than observed in the other cultivars, in the same treatment. This fact can also be seen in the BRS Pajeu cultivar, but only in plants subjected to 552 mg L^-1 of SA.

For Qayyum et al. (2021), RWC is an important indicator of plant water status, and its reduction can cause loss of cell turgidity and directly affect physiological processes, since they are directly linked to water status. Thus, the RWC reductions observed in the BRS Pujante and BRS Pajeu varieties with the imposition of water stress indicate a greater sensitivity of these variations to water deficit, corroborating the study by Gomes et al. (2020), while the cultivars BRS Novaera and BRS Tapaihum show greater tolerance, as no difference in RWC was noticed under the W50 depth (Figure 3A and B).

Therefore, the results indicate that SA can induce resistance to water restriction in cowpea, since it enabled increases in the RWC of the BRS Pajeu cultivar at the V7 phenological stage (Figure 3A) and in the BRS Pujante cultivar at the R2 stage (Figure 3B), which ensured the maintenance of cell turgidity, even under conditions of water deficit. Such findings are explained by the fact that SA favors the accumulation of osmoprotective molecules, which favor water absorption and maintain cell turgidity at ideal levels for the occurrence of metabolic processes (Jales Filho et al., 2023). Similar results were observed by Carvalho et al. (2020) in basil plants, as the RWC of plants subjected to water restriction and treated with SA was 44.5% higher than that of untreated plants.

In the absence of SA (0 mg L^-1), the water restriction of 50% ETc resulted in increased intracellular electrolyte leakage (IEL) in the cultivars BRS Novaera, BRS Tapaihum, and BRS Pajeu at stage V7 (Figure 4A). This same effect was observed in R2 stage for BRS Pajeu cultivar, for which a 25.6% increase in IEL was recorded with water restriction (Figure 4B). These results suggest that the reduction in water availability caused damage to cowpea cell membranes, leading to increased release of electrolytes due to membrane rupture and permeability (Khalvandi et al., 2021).

Figure 4
Intracellular electrolyte leakage (IEL) in cowpea cultivars at phenological stages V7 (A) and R2 (B) subjected to two irrigation depths and concentrations of salicylic acid

Under water deficit, photosynthesis can be restricted, leading to an accumulation of free electrons in plant metabolism and an increase in the production of reactive oxygen species (ROS) (Campos et al., 2019). At high concentrations, these molecules can promote the degradation of cellular structures and the peroxidation of the lipid membrane (Ventura et al., 2019). Therefore, the increase in IEL in the present study may have occurred due to the accumulation of ROS in response to water deficiency. It is noteworthy that the highest levels of IEL, at stage V7, were observed in the cultivars BRS Novaera and BRS Tapaihum, under water restriction and absence of SA (Figure 4A).

However, when spraying 276 and 552 mg L^-1 of SA at the V7 phenological stage, the BRS Novaera cultivar showed a reduction in IEL under both water conditions compared to plants that did not receive SA. It is also important to note that there was no difference between the irrigation depths with a concentration of 276 mg L^-1 of SA in this cultivar. In the case of BRS Pajeu, the concentration of 552 mg L^-1 of SA proved to be more effective in maintaining IEL. Plants subjected to this concentration of SA, even under water restriction, did not differ statistically from those under the 100% ETc level (Figure 4A). Furthermore, still at stage V7, the cultivars BRS Novaera and BRS Pujante, under water restriction and 276 mg L^-1 of SA, had IEL significantly lower than that observed in the cultivar BRS Pajeu (Figure 4A), indicating that the action of SA, in mitigating the effects of water stress, may vary according to the cultivar.

At the R2 phenological stage (Figure 4B), plants of the BRS Novaera cultivar, which were not sprayed with SA, had a 12% reduction in IEL when subjected to water restriction. Additionally, under 50% ETc, a 10.63% reduction in IEL was observed with the spraying of 276 mg L^-1 of SA in the BRS Pujante cultivar, compared to plants that did not receive SA under the same water condition, which indicates the beneficial role of SA in protecting cell membranes. In this case, it is also noteworthy that the IEL values ​​observed in BRS Pujante, with this SA concentration, were lower than those obtained by the other cultivars, which did not differ between themselves, nor from the control treatment (Figure 4B). At stage V7, it is noteworthy that lower IEL values ​​were observed with the spraying of 552 mg L^-1 of SA in the cultivars BRS Novaera (77.7%) and BRS Tapaihum (60.5%) - under the depth of 100% of ETc - which were significantly lower than the values ​​observed in plants that did not receive SA as elicitor.

Adjustments in electrolyte leakage with the application of SA may occur since the phytohormone acts in the regulation of antioxidant mechanisms (Ghahremani et al., 2023), in addition to being a non-enzymatic antioxidant. In this way, SA acts to eliminate reactive oxygen species and maintain the integrity of cell membranes (Oliveira et al., 2023).

Araújo et al. (2018) observed a reduction in electrolyte leakage in cowpea seedlings treated with 1.0 mM SA under water restriction. Similarly, Abdelaal et al. (2020) found lower IEL in barley (Hordeum vulgare L.) plants treated with SA when grown under water deficits compared to untreated plants.

At the V7 phenological stage, in the absence of spraying with SA, the water deficit (50% of ETc) resulted in a 36.3% decrease in the total fresh mass (TFM) of the BRS Novaera cultivar and a 32.7% reduction in the BRS Pajeu cultivar, compared to those irrigated with 100% of ETc (Figure 5A). It is important to note that a water deficit not only hinders cell expansion and division but can also alter plant metabolism and inhibit metabolic activities responsible for biomass production (Silva et al., 2019). This explains the reduction in growth indicated by TFM under water restriction.

Figure 5
Total fresh mass of plants of cowpea cultivars at phenological stages V7 (A) and R2 (B) subjected to two irrigation depths and concentrations of salicylic acid

The cultivar BRS Novaera showed a reduction in TFM in response to water deficit at stage V7. However, spraying 552 mg L^-1 of SA reversed this effect, resulting in a 100% increase in TFM compared to unsprayed plants under the same water condition and a 34% increase compared to those irrigated with 100% ETc. This was also observed with 100% replacement of ETc in the BRS Pajeu cultivar under spraying with 552 mg L^-1 of SA, which promoted a 28% increase in TFM compared to the control, which resulted in the highest TFM observed among the cultivars evaluated (Figure 5A).

Al Rawi et al. (2021) highlighted that SA, when absorbed by the vegetative part of plants, increases sap transfer, resulting in greater plant growth. In corn plants (Zea mays L.), Shemi et al. (2021) found that water deficit significantly reduced the fresh mass of plants; however, when they carried out foliar spraying of 140 mg L^-1 of SA, there was a reversal of the reduction in TFM, both in plants subjected to water stress conditions with 50% of field capacity and in plants irrigated with 85% of field capacity.

At stage R2 (Figure 5B), both BRS Novaera and BRS Pajeu cultivars showed a decrease in TFM due to water restriction in the absence of SA. The TFM of the BRS Novaera cultivar did not show significant differences in response to SA concentrations under the 50% ETc depth, while the BRS Pujante and BRS Pajeu cultivars expressed a reduction in TFM with the spraying of 552 mg L^-1 of SA under water restriction. A possible explanation for this result is that SA acts as an auxin antagonist, and thus can inhibit plant growth when applied at high concentrations (An & Mou, 2011). Effects similar to those found in this study were observed by Gastl-Filho et al. (2017) in cucumber plants, where the authors found a reduction in fresh mass with an increase in SA concentration.

At the R2 stage, there was a positive effect of SA on the TFM of the BRS Tapaihum and BRS Pujante cultivars with 100% water replacement, and the concentration of 552 mg L^-1 promoted increases of 36 and 113%, respectively, compared to the control (Figure 5B). At this phenological stage, the fact that the cultivar BRS Pajeu, under water restriction conditions, has a TFM higher than that observed in the other cultivars under 276 mg L^-1 of SA stands out. In turn, under the W100 depth, the cultivars BRS Pujante and BRS Pajeu stand out with the highest TFM values ​​at a concentration of 552 mg L^-1, although, for the cultivar BRS Pajeu, this result does not differ from that of plants that did not receive SA under the W100 depth (Figure 5B).

Water stress affected qualities in the relative growth of the shoot (SRGR) in the cultivar BRS Pujante, under the absence of SA, where the plants had SRGR 24.3% lower than that observed within the W100 depth. This fact is also observed in this same cultivar, in plants subjected to 552 mg L^-1 of SA, and in BRS Novaera, which express reductions of 52 and 53% with water restriction, a result similar to that observed in BRS Tapaihum (reduction of 47.4%), with plants subjected to a concentration of 276 mg L^-1 of SA. In turn, the BRS Pajeu cultivar shows an increase of 24.6% in SRGR under the application of 276 mg L^-1 of SA, under the W50 depth, compared to W100 (Figure 6).

Figure 6
Shoot relative growth rate of cowpea cultivars at phenological stages V7 (A) and R2 (B) subjected to two irrigation depths and concentrations of salicylic acid

It was possible to observe for all cultivars, except for BRS Pajeu, at each irrigation depth, that the highest SRGR values are observed in plants subjected to SA application, which indicates a beneficial effect of this substance on cowpea (Figure 6). Therefore, it is worth noting that BRS Novaera shows a significant increase in this variable when subjected to 276 mg L^-1 of SA under both water conditions. The BRS Tapaihum cultivar expresses higher SRGR values with the application of 276 and 552 mg L^-1 of SA under the W100 depth, and with 276 mg L^-1 of SA under the stress condition, compared to the control. The BRS Pujante cultivar has increased SRGR with a concentration of 552 mg L^-1 of SA under 100% ETc (Figure 6).

When comparing the cultivars, it is observed that, under water restriction and absence of SA, BRS Novaera, BRS Tapaihum and BRS Pujante had SRGR significantly lower than that observed in BRS Pajeu, which demonstrates a greater sensitivity of these varieties to the water restriction imposed in the experiment (Figure 6). However, it is noted that, under stress conditions, with the application of 276 mg L^-1 of SA, there is no statistical difference in SRGR between the cultivars BRS Novaera and Pajeu, which indicates a beneficial effect of this acid in inducing resistance to water stress in this cultivar. The highest SRGR is observed in the cultivar BRS Pujante, under 100% water replacement and 552 mg L^-1 of SA, indicating the beneficial role of SA in the growth of this cultivar, and that it may vary according to the cowpea variety.

The reductions in SRGR under water restriction observed in this study corroborate the results reported by Ayala et al. (2020), who found a 73.6% reduction in cowpea growth under water restriction. This behavior was also observed by Silva et al. (2019), as cultivars of the same species had reduced growth under stress conditions.

SA regulates plant growth and induces responses to water restriction (Carvalho et al., 2020; Oliveira et al., 2023). Effects similar to those observed in this study were also reported by Andrade et al. (2020), who also observed improved plant architecture with SA treatment, attributing this effect to the accumulation of osmoprotective molecules that lead to increased water status and photosynthetic rates.

Conclusions

1. Water restriction of 50% ETc decreased relative leaf water content in the BRS Pujante and BRS Pajeu cultivars, total fresh mass in the BRS Novaera and BRS Pajeu cultivars, and relative shoot growth rates the BRS Pujante cultivar, and increased intracellular electrolyte leakage in the cultivars BRS Novaera, BRS Tapaihum and BRS Pajeu.

2. Spraying with 276 mg L^-1 of salicylic acid (SA) is recommended to mitigate the effects of water restriction on water status and cellular integrity in the cultivars BRS Novaera, BRS Pujante and BRS Pajeu; and concentration of 552 mg L^-1 of SA in the growth of the BRS Novaera cultivar, under field conditions.

3. Maintaining the relative water content in the leaves, reducing intracellular leakage of electrolytes and increasing growth under conditions of water restriction, through the application of SA, with variation according to the cultivar and the phenological stage of the plants.

4. The BRS Novaera cultivar proved to be more responsive to the application of SA in the V7 phenological stage, under conditions of water restriction.

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• ¹ Research developed at Universidade Estadual da Paraíba, Lagoa Seca, PB, Brazil

Supplementary documents

• There are no supplementary documents.

Financing statement

• The authors declare financial support was received for the research, authorship, and/or publication of this article. To the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil, finance code 001. To the Conselho Nacional de Desenvolvimento Cientıfíco e Tecnológico - CNPq, for granting financial aid (Proc. 408952/2021-0 and 307559/2022-0) and the Fundação de Apoio à Pesquisa do Estado da Paraíba (Edital Fapesq- PB/CNPq no. 77/2022 and Edital no. 004/2018 - SEIRHMACT/Fapesq-PB).

Edited by

• Editors: Lauriane Almeida dos Anjos Soares & Walter Esfrain Pereira

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Publication Dates

• Publication in this collection
  20 Jan 2025
• Date of issue
  May 2025

History

• Received
  05 Feb 2024
• Accepted
  16 Oct 2024
• Published
  28 Nov 2024