Foliar Application Of Salicylic Acid Research Articles

Alleviation of Drought Stress Effects in Two Rice (Oryza sativa L.) Cultivars by Foliar Application of Salicylic Acid

Alleviation of Drought Stress Effects in Two Rice (Oryza sativa L.) Cultivars by Foliar Application of Salicylic Acid

Salicylic Acid and Superabsorbent Polymers Could Alleviate Water Deficit Stress in Camelina (Camelina Sativa L.)

ABSTRACT Agronomic management and application of growth regulators mitigated the negative effects of water deficit and improved seed oil yield and other traits in camelina. This study assessed the effects of salicylic acid (SA) foliar application and soil application of superabsorbent polymer hydrogel (SPH) on the growth and antioxidant production of camelina (Camelina sativa L.) in 50% and 75% field capacity (FC) groups, as well as in a well-watered treatment. Application of SA and SPH significantly increased camelina yield and its components in 75% FC and well-watered treatments. In the control (no SA or SPH), water deficit reduced seed oil by 13% and 35% in 75% FC and 50% FC, respectively. Application of SA and SPH increased seed oil by 5% and 11%, respectively. Photosynthetic rate (A), stomatal conductance (gs), and chlorophyll content decreased in the 75% FC and 50% FC treatments. Application of SA and SPH increased in A (26% and 19%) and gs (17% and 12%) compared to the control. Superoxide dismutase (SOD), peroxidases (POD), catalases (CAT), and ascorbate peroxidase (APX) activity increased with increased drought stress. The activity of these enzymes increased when SA was applied. Generally, foliar application of SA was more effective than soil application of SPH in camelina to alleviate the injurious effects of drought stress.

Response of Rice (Oryza sativa L.) Varieties to Salicylic Acid, Potassium Silicate and Tamarind Extract in Saline Soils of Kano River Irrigation Scheme Nigeria

The experiment was carried out in the Eastern and Western sectors of Kano River Irrigation Scheme, Kano State latitude 11º 45’N and 12º 05’ N and longitude 8º 45’ E and 9º 05’ E in the Sudan Savanna Agro-ecology of Nigeria, during the dry season of 2020 and 2021. The experiment was therefore conceived with the aim of introducing improved salt tolerant varieties to farmers in addition to enhancing their tolerance using synthetic and natural plant growth regulators. The treatments consisted of four rice varieties made up of 2 salt tolerant accessions {Arica 1 and Arica 2, 1 blast resistant variety (Gawal R1) and a variety (FARO 44) as a check} these were factorially combined with foliar application of salicylic acid (0.2g in 1L of water), potassium silicate (16 g/L-1 of K2SiO3), tamarind extract 8% (320ml of extract in 1 liter of water) and a zero control (0). The treatments were laid out in a Randomized Complete Block Design (RCBD) which consisted of 16 treatments replicated six times with a farmer constituting a replication. Results have shown that plant height, leaf area index (LAI), photosynthetically active radiation (PAR), chlorophyll content and the yield were all significantly affected by varietal differences except total number of tillers per plant in 2020. However, in 2021 LAI, PAR and chlorophyll content were not significantly affected by differences due to varieties but the remaining characters differed significantly. Exogenous factors had no effect on all the characters in 2020 but significantly influenced the chlorophyll content, total number of tillers and the yield in 2021. Arica 1 and Faro 44 gave the highest yield. Among the exogenous factors Tamarind extract had significantly heavier paddy yield than the control but was similar to other exogenous factors in terms of effectiveness. Tamarind extract could therefore be suggested to farmers when growing rice under saline or sodic condition in the irrigation scheme due to its lower cost and availability.

Foliar application of salicylic acid inhibits the cadmium uptake and accumulation in lettuce (Lactuca sativa L.).

Salicylic acid (SA) is a multi-functional endogenous phytohormone implicated in the growth, development, and metabolism of many plant species. This study evaluated the effects of different concentrations of SA (0, 25, 100, 200, and 500 mg/L) on the growth and cadmium (Cd) content of lettuce (Lactuca sativa L.) under Cd stress. The different concentrations of SA treatments were administered through foliar application. Our results showed that 100-200 mg/L SA significantly increased the plant height and biomass of lettuce under Cd stress. When SA concentration was 200 mg/L, the plant height and root length of lettuce increased by 19.42% and 22.77%, respectively, compared with Cd treatment alone. Moreover, 200 mg/L and 500mg/L SA concentrations could reduce peroxidase (POD) and superoxide dismutase (SOD) activities caused by Cd stress. When the concentration of exogenous SA was 500 mg/L, the POD and SOD activities of lettuce leaves decreased by 15.51% and 19.91%, respectively, compared with Cd treatment. A certain concentration of SA reduced the uptake of Cd by the lettuce root system and the transport of Cd from the lettuce root system to shoots by down-regulating the expression of Nramp5, HMA4, and SAMT, thus reducing the Cd content of lettuce shoots. When the concentration of SA was 100 mg/L, 200 mg/L, and 500 mg/L, the Cd contents of lettuce shoots were 11.28%, 22.70%, and 18.16%, respectively, lower than that of Cd treatment alone. Furthermore, principal component and correlation analyses showed that the Cd content of lettuce shoots was correlated with plant height, root length, biomass, antioxidant enzymes, and the expression level of genes related to Cd uptake. In general, these results provide a reference for the mechanism by which SA reduces the Cd accumulation in vegetables and a theoretical basis for developing heavy metal blockers with SA components.

Salicylic acid does not alleviate salt stress on physiological indicators and growth of guava

In the semi-arid region, the quality of water for irrigation stands out as a limiting factor for the expansion ofagriculture. Thus, it is extremely important to search for alternatives that minimize the effects of salt stress onplants. Foliar application of salicylic acid stands out among these strategies. In this context, the objective ofthis study was to evaluate the gas exchange, photosynthetic pigments, and growth of guava as a function ofirrigation water salinity and exogenous application of salicylic acid in the post-grafting stage. The experimentwas conducted under greenhouse conditions, in a randomized block experimental design, in a 2 × 4 facto rialscheme, corresponding to two levels of electrical conductivity of irrigation water (0.6 and 3.2 dS m-1) and fourconcentrations of salicylic acid (0; 1.2; 2.4 and 3.6 mM), with three replicates. Irrigation with water of 3.2 dS m-1caused reductions in transpiration, CO2 assimilation rate, instantaneous water use efficiency and instantaneouscarboxylation efficiency of guava, at 150 days after transplanting. Water with electrical conductivity of 3.2 dSm-1 reduced the growth in stem diameter and the absolute and relative growth rates, as well as the relativewater content, and chlorophyll a and b contents of guava plants. The interaction between water salinity levelsand salicylic acid concentrations did not influence the physiological indices and growth of guava in the postgraftingphase.

Synergistic Effects of Rhizobacteria and Salicylic Acid on Maize Salt-Stress Tolerance.

Maize (Zea mays L.) is a salt-sensitive plant that experiences stunted growth and development during early seedling stages under salt stress. Salicylic acid (SA) is a major growth hormone that has been observed to induce resistance in plants against different abiotic stresses. Furthermore, plant growth-promoting rhizobacteria (PGPR) have shown considerable potential in conferring salinity tolerance to crops via facilitating growth promotion, yield improvement, and regulation of various physiological processes. In this regard, combined application of PGPR and SA can have wide applicability in supporting plant growth under salt stress. We investigated the impact of salinity on the growth and yield attributes of maize and explored the combined role of PGPR and SA in mitigating the effect of salt stress. Three different levels of salinity were developed (original, 4 and 8 dS m-1) in pots using NaCl. Maize seeds were inoculated with salt-tolerant Pseudomonas aeruginosa strain, whereas foliar application of SA was given at the three-leaf stage. We observed that salinity stress adversely affected maize growth, yield, and physiological attributes compared to the control. However, both individual and combined applications of PGPR and SA alleviated the negative effects of salinity and improved all the measured plant attributes. The response of PGPR + SA was significant in enhancing the shoot and root dry weights (41 and 56%), relative water contents (32%), chlorophyll a and b contents (25 and 27%), and grain yield (41%) of maize under higher salinity level (i.e., 8 dS m-1) as compared to untreated unstressed control. Moreover, significant alterations in ascorbate peroxidase (53%), catalase (47%), superoxide dismutase (21%), MDA contents (40%), Na+ (25%), and K+ (30%) concentration of leaves were pragmatic under combined application of PGPR and SA. We concluded that integration of PGPR and SA can efficiently induce salinity tolerance and improve plant growth under stressed conditions.

Improving photosynthesis and drought tolerance in Nicotiana tabacum L. by foliar application of salicylic acid

Drought causes a decrease in tobacco yield and quality as well as a reduction in net photosynthetic rate. Salicylic acid (SA) is involved in the regulation of many physiological processes and has been widely used to improve plant drought tolerance. The hydroponic experiment was carried out on flue-cured tobacco variety K326. SA solutions (0.3 mM) were sprayed on the leaves every day for three days, after which 15% PEG-6000 was used to simulate moderate drought. The results showed that drought stress reduced the photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr), while it enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), malondialdehyde (MDA), proline and protein content. Compared with PEG drought stress, SA improved the Pn, Gs and Tr by 45.74%, 26.82%, and 52.22% respectively. Besides, the activities of SOD, POD, CAT, protein and proline content increased by 44.27%, 50.18%, 25%, 34.69% and 24.88%, respectively, while the MDA content decreased by 23.89%. Furthermore, SA spraying increased the drought tolerance of tobacco by modulating the expression level of the genes associated with photosynthesis, carbon metabolism, and photosynthesis-antenna proteins. Hence, SA spraying reduced the inhibition of drought on photosynthesis and stimulated the antioxidant system, thus improving the drought resistance in tobacco.

Expression Analysis of Trihelix Transcription Factor Family in Strawberries and Functional Characterization of FvTrihelix6

The Trihelix is a plant-specific transcription factor family and has critical roles in plant growth and development and stress resistance. There is less information about Trihelix transcription factor genes and their potential functions in strawberries (Fragaria vesca). In the present study, we performed a detailed bioinformatics analysis of the Trihelix family in strawberries including physicochemical properties, chromosomal location, exon–intron distribution, domain arrangement, and subcellular localization. Thirty Trihelix family members were identified and divided into five subfamilies. The expression of FvTrihelix genes in different tissues/organs, i.e., root, stolon, leaf, flower, and fruit, was measured in strawberries after infection with Colletotrichum. gloeosporioides and foliar applications of salicylic acid (SA) and jasmonic acid (JA). Most of the genes showed differential expression responses following C. gloeosporioides infection and hormone treatments (SA and JA), suggesting critical roles in disease resistance and hormonal signaling pathways. As anticipated, the ectopic expression of FvTrihelix6 in Arabidopsis thaliana increased resistance against Colletotrichum. higginsianum infection. FvTrihelix6 protein was localized in the nucleus. We surmise that FvTrihelix6 enhances resistance against pathogens through the SA and JA signaling pathways. This study provides novel insights into the strawberry Trihelix transcription factor genes and new candidates for disease-resistance breeding of strawberries.

Foliar Application of Salicylic Acid and Zinc Sulphate Levels on Growth and Yield of Squash under Net House Condition

A field experiment was conducted at Horticulture Farm of Sher-e-Bangla Agricultural University, Dhaka during November, 2020 to February, 2021. The experiment was laid out in a Randomized Complete Block Design with three replications. The experiment had two factors (Different levels of salicylic acid, S0= No salicylic acid (control), S1= 60 ppm of salicylic acid, S2= 90 ppm of salicylic acid and different levels of zinc, Z0= No zinc sulphate (control), Z1= 25 ppm of zinc sulphate, Z2= 50 ppm of zinc sulphate. Different levels of salicylic, zinc sulphate and also their combinations showed significant influence on different growth, yield contributing parameters and yield of squash. The treatment, S2 showed highest results in fruit yield per plant (2422.7 g), fruit yield per plot (9.68 kg) and fruit yield per ha (37.83 t) compared to control. In case of zinc treatments, the highest results in fruit yield per plant (2597.1 g), highest fruit yield per plot (10.38 kg) and highest fruit yield per ha (31.74 t) were found from Z1 compared to control. Likewise, the treatment combination of S2Z1 (90 ppm of salicylic acid and 25 ppm of zinc sulphate) gave the highest fruit yield per plant (3045.4 g) fruit yield per plot (12.18 kg) and highest yield per ha (47.57 t) where the lowest results were found from the treatment combination of S0Z0 (control). The highest gross return (BDT 1189425), net return (BDT 881669) and BCR (3.86) were obtained from the treatment combination of S2Z1 where the lowest was obtained from S0Z0. It can be concluded that from economic point of view, S2Z1 (90 ppm of salicylic acid and 25 ppm of zinc sulphate) treatment combination is suitable for squash cultivation than other treatment combinations.

Foliar Applications of Salicylic Acid on Boosting Salt Stress Tolerance in Sour Passion Fruit in Two Cropping Cycles.

Brazil stands out as the largest producer of sour passion fruit; however, the water available for irrigation is mostly saline, which can limit its cultivation. This study was carried out with the objective of evaluating the effects of salicylic acid in the induction of tolerance in sour passion fruit to salt stress. The assay was conducted in a protected environment, using a completely randomized design in a split-plot scheme, with the levels of electrical conductivity of the irrigation water (0.8, 1.6, 2.4, 3.2, and 4.0 dS m-1) considering the plots and concentrations of salicylic acid (0, 1.2, 2.4, and 3.6 mM) the subplots, with three replications. The physiological indices, production components, and postharvest quality of sour passion fruit were negatively affected by the increase in the electrical conductivity of irrigation water, and the effects of salt stress were intensified in the second cycle. In the first cycle, the foliar application of salicylic acid at concentrations between 1.0 and 1.4 mM partially reduced the harmful effects of salt stress on the relative water content of leaves, electrolyte leakage, gas exchange, and synthesis of photosynthetic pigments, in addition to promoting an increase in the yield and quality parameters of sour passion fruit.

Foliar application of salicylic acid improved the yield and quality of the essential oil from Dracocephalum kotschyi Boiss. under water deficit stress

Foliar application of salicylic acid improved the yield and quality of the essential oil from <i>Dracocephalum kotschyi</i> Boiss. under water deficit stress

Foliar application of salicylic acid and chitosan on the growth and quantity and quality of the essential oil from lemon balm (Melissa officinalis L.)

Foliar application of salicylic acid and chitosan on the growth and quantity and quality of the essential oil from lemon balm (<i>Melissa officinalis</i> L.)

Ácido salicílico nas trocas gasosas e crescimento de mudas de Hymenaea courbaril L. sob alagamento

ABSTRACT Flooding is a stressful condition that causes damage to the photosynthetic apparatus, negatively affecting the growth of seedlings of fruit species, including Hymenaea courbaril L. Studies on physiological management, such as exogenous application of phytohormones, to alleviate abiotic stress have increased. The objective of this study was to evaluate the effect of foliar application of salicylic acid (SA) on H. courbaril seedlings subjected to flooding. The seedlings received foliar application of four concentrations of SA (0, 100, 200, and 400 mg L-1) and were subjected to two water regimes: a) control - non-flooded and irrigated daily and b) flooded - seedlings were placed in a plastic pool, keeping the water depth at ± 5.0 cm above the substrate level. After 35 days, we evaluated the gas exchange, initial growth, quality, and potential ecological resilience of the seedlings. All flooded seedlings survived, but had reduced photosynthesis, carboxylation of Rubisco efficiency, and water-use and stomatal conductance when they received 100-300 mg L-1 SA. The seedlings that received between 100 and 300 mg L-1 SA had greater growth, quality, and phenotypic plasticity. Foliar application of SA did not mitigated the effect of flooding on gas exchange but contributed to the growth of H. courbaril seedlings.

Foliar spray of salicylic acid and ascorbic acid ameliorates the biochemical compounds in hybrid chillies

Chillies (Capsicum annuum) are a spice crop with great medicinal value of its biochemical ingredients. Its high antioxidant value along with good nutritional properties. Foliar application of Salicylic Acid may stimulate various plant physiological parameter i.e., stomatal activity, ions uptake, seed germination, leave membrane response to electrolytes and growth rate. Salicylic Acid (SA) is known as a molecule that is participated in physiological processes in chillies, plant tolerance and resistance to abiotic and biotic stresses. Ascorbic acid possesses antioxidant properties, has positive impact on flowering and expounds effective plant defense system against pesticide toxicity. Moreover, ascorbic acid is effective chemical to mitigate the destructive impacts of salt stress. All the treatments improved the yield, fruit length and fruit width as compared to control treatment. Although, various treatments, salicylic acid and ascorbic acid combination showed the maximum plant height (80.3 cm), shoot weight (161 g), root weight (47.1 g) and pericarp thickness (1.99 mm) in treatment T9 variety of V4. Results declared that foliar spray of plants growth regulators increased the carbohydrates, protein, fiber and ash content. Results declared that foliar spray of plants growth regulators increased the carbohydrates, protein, fiber and ash contents. Furthermore, Biochemical attributes and Enzymes like proline (19.1%), SOD (1.40ug-1Fw), POD (17.9 ug-1Fw g) and CAT (6.15ug-1Fw) were significantly improved in plants sprayed with salicylic acid (SA) and ascorbic acid (AA) at T9 treatment. The objective of this study was to evaluate the effect of foliar application of ascorbic acid and salicylic acid on the yield and biochemical traits of hybrid chillies. Generally, the highest values were obtained from T9 treatment application of SA and AA combination. Based on these findings, the SA and AA treatments may help alleviate the positive effect on the growth of Chillies.

Salicylic acid alleviates the effects of salt stress on the physiology, growth, and production of hydroponic okra

Application of salicylic acid can enable the use of brackish water in the hydroponic cultivation of okra in arid and semi-arid regions. In this context, the objective of the present study was to evaluate the effect of foliar application of salicylic acid in mitigating the impacts of salt stress on the physiology, growth, and production of “Canindé” okra cultivated in a hydroponic system. The experiment was carried out in a greenhouse, using an NFT—Nutrient Film Technique hydroponic system. A completely randomized design was adopted in a split-plot scheme, with four levels of electrical conductivity of the nutrient solution—ECns (2.1, 3.6, 5.1, and 6.6 dS m−1) considered as plots and four concentrations of salicylic acid—SA (0, 1.2, 2.4, and 3.6 mM), considered as subplots, with four replications, each of which consisting of two plants. Foliar application of salicylic acid at a concentration of 1.2 mM attenuated the harmful effects of salt stress on the physiology, growth, and production components of “Canindé” okra cultivated in a hydroponic system with ECns of up to 6.6 dS m−1. Plants cultivated with ECns of 6.6 dS m−1 and salicylic acid at a concentration of 1.2 mM obtained an increase of 11.13% (36.4 g per plant) in total production per plant compared to plants cultivated with the same ECns level and without application of salicylic acid. These results demonstrate that salicylic acid, when supplied by foliar application at adequate concentrations, can act as a signaling molecule and reduce the effects of salt stress on hydroponic okra.

Response of Different Levels of Salicylic Acid on Growth Characteristics, Chlorophyll Content, Yield Attributes and Yield of Black Gram (Vigna mungo L.) under Rainfed Condition

To study the response of different levels of salicylic acid on growth characteristics, chlorophyll intensity, yields attributes and yield of black gram (Vigna mungo L.) under rainfed conditions. The field experiment was conducted at Department of Crop Physiology, Chandra Shekhar Azad University of Agriculture &amp; Technology, Kanpur, Uttar Pradesh, India during kharif season in the year 2017-18. The experiment was laid out in Randomized Block Design (RBD) with 10 Treatments replicated thrice and assigned in 30 plots. The treatment comprised as T1: Control, T2: Foliar application of salicylic acid @ 50 ppm at 20 DAS, T3: Foliar application of salicylic acid @ 50 ppm at 40 DAS, T4: Foliar application of salicylic acid @ 50 ppm at 60 DAS, T5: Foliar application of salicylic acid @ 100 ppm at 20 DAS, T6: Foliar application of salicylic acid @ 100 ppm at 40 DAS, T7: Foliar application of salicylic acid @ 100 ppm at 60 DAS, T8: Foliar application of salicylic acid @ 150 ppm at 20 DAS, T9: Foliar application of salicylic acid @ 150 ppm at 40 DAS, T10: Foliar application of salicylic acid @ 150 ppm at 60 DAS. The results showed significant increments in Growth attributes, relative water content (%), chlorophyll intensity (SPAD meter value), yield and yield attributes viz., plant height (36.50 and 38.10 cm) at 70 DAS and maturity, number of leaves plant-1(8.66, 23.66 and 22.0) at 35, 70 DAS and maturity, number of branches plant-1 (3.9, 8.60 and 10.33) at 35, 70 DAS and maturity, dry weight of plant-1(2.76, 6.12 and 5.01 g) at 35, 70 DAS and maturity, dry weight of stem plant-1(2.76, 7.12 and 7.96 g) at 35, 70 DAS and maturity, total dry weight of plant (4.96, 13.24 and 21.97 g) at 35, 70 DAS and maturity, total leaf area plant-1 (211.33 and 384.87 cm-2) at pre and post flowering, Relative water content (51.50 and 43.43) at Pre and post flowering, Chlorophyll content (49.93 and 40.90) at pre and post flowering, Number of pods plant-1 (46.00) at maturity, Dry weight of pods plant-1 (8.99g) at maturity, seed yield plant-1 (6.66 g), 100-Seed weight (4.41 g), Harvesting index (30.30%), Grain Yield (10.35 q ha-1) with the foliar application of salicylic acid @ 150 ppm at 60 DAS while minimum in control. The addition of salicylic acid under rainfed conditions resulted in significant increments in growth parameters, chlorophyll intensity, yield and yield attributes of black gram in rainfed conditions. Thus, it may be concluded that the foliar application of salicylic acid @ 150 ppm was found to be optimum concentration in enhancing growth and yield of a black gram over rest of treatment under rainfed conditions.

Assimilate Partitioning and Photosynthetic Parameters of Rice (Oryza sativa L.) in Response to Salicylic Acid Application

Salicylic acid (SA), a signaling molecule is known to affect various physiological processes like growth and development, photosynthesis, absorption and translocation of assimilates etc. Therefore, an experiment was conducted to study the effect of salicylic acid on assimilate partitioning and yield of rice. The experiment comprised of 14 treatments replicated thrice in Randomized Complete Block Design (RCBD). Foliar application of SA @ 50, 100, 150 &amp; 200 µg ml-1 was done at boot leaf stage (BL), one week after boot leaf stage (1WABL) and at BL + 1WABL. Treatment of water spray and unsprayed (control) were also included. Findings reveal that application of 100 µg ml-1 SA at BL + 1WABL resulted in the highest grain yield, which was statistically similar to 150 µg ml-1 SA at BL + 1WABL. The higher productivity under respective treatments can be ascribed to higher crop growth rate, relative growth rate, net assimilation rate and improvement in partitioning of dry matter from vegetative parts to grains due to improved vascularization. Also there was improvement in photosynthetic efficiency in terms of total chlorophyll content; carotenoid content and Hill reaction activity under SA treated plots. Thus, the productivity enhancement in rice can be achieved through 2 foliar sprays of salicylic acid @ 100 µg ml-1 each at boot leaf stage + one week after boot leaf stage.

Chemical composition of the essential oil of in vitro propagated Mentha x piperita L. and Mentha pulegium L. under methyl jasmonate and salicylic acid foliar application in field conditions

Chemical composition of the essential oil of <i>in vitro</i> propagated <i>Mentha x piperita</i> L. and <i>Mentha pulegium</i> L. under methyl jasmonate and salicylic acid foliar application in field conditions

Ameliorative role of salicylic acid in the growth, nutrient content, and antioxidative responses of salt-stressed lettuce

Plant responses to biotic and abiotic stresses are regulated by salicylic acid (SA), a signaling molecule. The goal of this study was to determine the efficacy of foliar SA treatments (0.25, 0.50, or 1.00 mM) in reducing salt stress in lettuce exposed to 100 mM NaCl. Salt-stressed plants given a foliar application of SA showed alleviation of the negative effects of salinity, resulting in higher growth performance (increases of 6%–198%). The positive impacts of SA were especially noticeable as an increase in the content of photosynthetic pigments, such as total chlorophyll (31–72%) and total carotenoids (49–141%). Application of SA also helped to reduce membrane damage, as seen by significantly lower levels of MDA (31–70%) in the leaves of salt-stressed lettuce plants. Moreover, the use of SA enhanced overall flavonoid and phenolic content, as well as nutrient absorption. SA treatment also increased the activities of antioxidant enzymes, such as ascorbate peroxidase, catalase, glutathione reductase, and superoxide dismutase, resulting in a considerable reduction in salt-induced oxidative damage. The most efficient SA application concentration was 0.50 mM. Overall, the use of SA as a foliar spray could be recommended as a long-term strategy for improving the defense systems of salt-stressed lettuce.

Foliar Application of Salicylic Acid Mitigates Saline Stress on Physiology, Production, and Post-Harvest Quality of Hydroponic Japanese Cucumber

Salicylic acid (SA) is a phenolic compound capable of inducing physiological and metabolic changes that enhance the tolerance of plants to saline stress associated with using a hydroponic system and enable the use of saline water in semi-arid regions. In this context, this assay aimed to evaluate the impact of the foliar application of SA on mitigating salt stress effects on Japanese cucumber cultivated in a hydroponic system. The experiment was carried out in a protected ambient (greenhouse), using the Nutrient Film Technique—NFT hydroponic system. A completely randomized design was performed in a 4 × 4 split-plot scheme, with four levels of electrical conductivity of the nutrient solution—ECns (2.1, 3.6, 5.1, and 6.6 dS m−1)—considered as plots and four SA concentrations (0, 1.8, 3.6, and 5.4 mM), regarded as subplots, with four replicates and two plants per plot. An increase in the ECns negatively affected the physiology, production components, and post-harvest quality of cucumber. However, the application of SA to leaves at concentrations between 1.4 and 2.0 mM reduced the deleterious effects of saline stress and promoted an increase in the production of and improvement in the post-harvest quality of cucumber fruits.