Impaginato 145 Adv. Hort. Sci., 2022 36(2): 145­153 DOI: 10.36253/ahsc­12015 Salinity effects on growth, chlorophyll content, total phenols, and antioxidant activity in Salvia lavandulifolia Vahl. H. Bayat (*), F. Shafie, B. Shahraki Department of Horticultural Science, College of Agriculture, University of Birjand, Birjand, Iran. Key words: Biomass, electrolyte leakage, total flavonoids, water content. Abstract: Although the effect of salinity stress on some species of Salvia has been studied, so far no research has been done on S. lavandulifolia species. Therefore, a greenhouse pot experiment was carried out to investigate the impacts of salt stress on vegetative parameters, chlorophyll content, and antioxidants activity in Salvia lavandulifolia Vahl. Treatments included different irrigation water salinity levels (S0=1.3, S1=3.3, S2=5.3, S3=7.3, S4=9.3, S5=11.3, and S6=13.3 dS m­1) which were arranged in a completely randomized design. The results showed that salinity treatments significantly affected the plant growth attributes. The lowest plant height, leaf number, leaf length, and shoot dry weight was recorded in the S6 treated plants with 62%, 41%, 44%, and 82% decrease compared to the control, respectively. Treatment of S. lavandulifolia plants with the highest salinity level (S6) decreased the content of chlorophyll a, chlorophyll b, and total chlorophyll by 57%, 53%, and 54% compared to the control, respectively. Salt stress at all levels increased the total phenolic con­ tent, and the highest value was obtained in the S6 treated plants. Free radical scavenging capacity was significantly increased by all the levels of salinity stress, and the highest (85.14%) value was obtained in the S6 treated plants. In general, S. lavandulifolia can be classified as a species­sensitive plant. 1. Introduction The genus Salvia, belonging to the Lamiaceae family, has about 1000 species worldwide (Walker et al., 2004; Will and Claßen­Bockhoff, 2017). Different species of Salvia have various applications in the pharmaceutical and therapeutic industries due to their antibacterial, antifungal, anti­ tumor, and antioxidant properties. It is traditionally used to treat bronchi­ tis, colds, sore throats, gastrointestinal disorders, eczema, and tuberculo­ sis (Li et al., 2013; Bahadori et al., 2015). Terpenoids and phenolic compounds are the main secondary metabolites of the genus Salvia (Lu and Foo, 2002). Salvia lavandulifolia Vahl. is a perennial herbaceous plant native to South France, Spain, and Northwest Africa. This species is well adapted to the semi­arid Mediterranean climate and grows up to 100 cm height and has opposite green or gray­white leaves. Several secondary (*) Corresponding author: hassanbayat@birjand.ac.ir Citation: BAYAT H., SHAFIE F., SHAHRAKI B., 2022 ­ Salinity effects on growth, chlorophyll content, total phenols, and antioxidant activity in Salvia lavandulifolia Vahl. ­ Adv. Hort. Sci., 36(2): 145­ 153. Copyright: © 2022 Bayat H., Shafie F., Shahraki B. This is an open access, peer reviewed article published by Firenze University Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no competing interests. Received for publication 4 September 2021 Accepted for publication 2 March 2022 AHS Advances in Horticultural Science https://doi.org/10.36253/ahsc-12015 http://www.fupress.net/index.php/ahs/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2022 36(2): 145­153 146 metabolites including polyphenolics, flavonoids, triterpenes and monoterpnes have been extracted from the aerial parts S. lavandulifolia (Amalia and Kintzios, 2005). Salinity stress is considered one of the most signifi­ cant environmental stresses that restrict the growth and yield of plants, especially in arid and semi­arid areas (Deng et al., 2015). In these areas, low rainfall, high evaporation, and poor drainage increase salt concentration in the soil and create salinity stress (Abdel Latef, 2010). Due to the scarcity or low quality (saline waters) of water resources worldwide, the management of crop production in saline conditions is critical. Salinity stress occurs with the accumulation of salts, especially sodium chloride, in the root zone. It causes disturbances in vital plant processes such as nutrient uptake and transport, transpiration, photo­ synthesis, and biosynthesis of primary and secondary metabolites (Valifard et al., 2014; Ahanger and Agarwal, 2017). Salinity stress impairs plant growth and development by increasing the osmotic potential of the soil solution, disturbing the nutrient balance, and the toxicity caused by the accumulation of sodi­ um (Na+) and chlorine (Cl­) ions (Rehman et al., 2019). Salinity stress increases reactive oxygen species (ROS) in the cells that damage nucleic acids, proteins, and membrane lipids (Foyer, 2018). The decrease in growth, dry matter production, and yield were report­ ed in most plants such as Salvia hispanica, feverfew (Tanacetum parthenium L.), and Salvia splendens due to salinity stress (Raimondi et al., 2017; Mallahi et al., 2018; Karimian et al., 2019). Karimian et al. (2019) reported that salt stress treatments (0, 20, 40, 60, and 80 mM NaCl) caused the decrease in growth parame­ ters, relative water content, chlorophyll content and increase electrolyte leakage, total phenols and total soluble sugars in Salvia splendens. Gengmao et al. (2014) demonstrated that salt treatments less than 100 mM NaCl had no effect on growth parameters of Salvia miltiorrhiza, but significantly decreased the accumulation of dry matter. In Salvia officinalis, the decrease in plant height, chlorophyll content, and essential oil content were reported due to salinity stress (150 mM NaCl) (Es-sbihi et al., 2021). Plants have developed different physiological, biochemical, and molecular mechanisms to deal with salinity stress (Zhao et al., 2020). Osmotic regulation is one of the mechanisms for maintaining cellular turgidity and membrane stability. In the osmotic reg­ ulation process, cellular concentrations of osmotical­ ly compatible solutes such as sugars increased (Chakhchar et al., 2015). Moreover, plants to deal with oxidative stresses enhance enzymatic and non­ enzymatic antioxidant activities to reduce the delete­ rious effects of the ROS (Acosta­Motos et al., 2017; Bayat and Moghadam, 2019). The increasing population of the world coupled with the depletion of freshwater resources and the salinization of agricultural lands necessitates further studies on plants resistant to adverse environmental conditions. Although the effect of salinity stress on some species of Salvia has been studied (Valifard et al., 2014; Raimondi et al., 2017; Karimian et al., 2019), so far no research has been done on S. lavan‐ dulifolia species. Considering the medicinal impor­ tance of Salvia lavandulifolia, it is necessary to inves­ tigate the tolerance to salt stress. Hence, this study was aimed to study the effects of salt stress on vege­ tative and physiological indices and some secondary metabolites in Salvia lavandulifolia. 2. Materials and Methods Plant materials and experimental design This study was carried out in Research Greenhouse, Faculty of Agriculture, University of Birjand, Iran. Salvia lavandulifolia var. Lavandulifolia seeds were purchased from Jelitto Seed Co (Germany) and sown in 105 cell seedling trays in April 2017. Coco peat and peat with a ratio of 1:1 were used for the substrate. Irrigation was done daily dur­ ing the seedling emergence and growth. After forty days, the seedlings were transplanted into 3­liter plastic pots at the 6­8 leaf stage. The physiochemical characteristics of the soil are given in Table 1 (Sparks, 1996). Organic matter (OM) was determined by the Walkley­Black method, and soil texture was mea­ Texture pH EC dS m­1 Organic matter Field capacity (FC) (%) N K meq lit­1 Ca meq lit­1 Na meq lit­1 Cl meq lit­1 Mg meq lit­1 Sodium adsorption ratio (SAR) Sandy loam 7.9 1.3 0.3 17.8 0.02 8.27 8.61 23.1 25.3 1.49 10.28 Table 1 ­ Some physicochemical characteristics of the experimental soil sample Bayat et al. ‐ Salinity effects on vegetative parameters of Salvia lavandulifolia 147 sured by the hydrometer method. Soil pH and electri­ cal conductivity (EC) were measured with pH meter (HANNA HI2211­02, USA) and EC meter (Jenway EC meter, Germany), respectively. Phosphorus (P), potassium (K), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) were extracted by the Mehlich 1 extracting solution. Sodium and potassium concen­ trations were measured by a flame photometer. Phosphorus was determined colorimetrically, and Cu, Zn, Fe, and Mn were measured by atomic absorption spectroscopy. Calcium and Mg were extracted with 1 M potassium chloride and determined by titration with ethylenediaminetetraacetic acid (EDTA). Chlorine was determined by titration method. The SAR was calculated by computing Na+, Ca2+ and Mg2+ concentrations (in meq/L) from the saturation extract. The experiment was conducted under green­ house conditions at temperatures of 25/20°C and rel­ ative humidity of 50­60%. The salinity stress started four weeks after the transplantation of seedlings into the pots. A com­ pletely randomized design with four replications was used to compare seven different irrigation water salinity treatments (S0=1.3, S1=3.3, S2=5.3, S3=7.3, S4=9.3, S5=11.3, and S6=13.3 dS m­1). To prepare solutions S1, S2, S3, S4, S5, and S6, sodium chloride (NaCl) was dissolved in irrigation water in the amounts of 1.14, 2.18, 3.27, 4.43, 5.49, and 6.65 g, respectively. Some physicochemical parameters of control water (S0) were: EC= 1.3 dS m­1, pH= 7.79, Na= 5.6 meq l­1, Cl= 6.8 meq l­1, and K= 0.35 meq l­1. The pots were irrigated twice a week with saline water based on the field capacity by pot weighting. Salinity treatments were applied for one month, and then the traits were measured. Growth indices Plant height, leaf number, leaf length, leaf width, and maximum root length were measured. To deter­ mine the dry weight of shoots and roots, the samples were dried in an oven for 48 hours (78°C) (Bayat et al., 2016). Relative water content (RWC) and electrolyte leakage (EL) The leaf RWC was measured using the method reported by Gonzalez and Gonzalez­Vilar (2003) and calculated according to the formula: RWC = (Fresh weight ­ Dry weight)/ (Turgid weight ­ Dry weight) x 100 Leaf dry weight was measured after oven­drying of the samples for 48 h (78°C). Turgid weight was determined after soaking leaves in distilled water in the refrigerator for 6 h. Electrolyte leakage (EL) of the leaf was measured based on the method reported by Lutts et al. (1996) and calculated according to the formula: EL= (EC1/EC2) × 100 where EC1 and EC2 are the primary and sec­ ondary electrical conductivities, respectively. Fresh leaves (0.5 g) were dispensed with distilled water (10 ml) in test tubes and then were shaken for 24 hours (24°C). The EC1 was measured by the EC meter. The test tubes were then transferred to an autoclave (121°C) for 15 minutes and EC2 was determined. Chlorophyll content and total soluble sugars The pigments of fresh leaves (0.1 g) were extract­ ed by 5 ml of acetone 80%. The amount of chloro­ phyll a and b were measured by a spectrophotome­ ter (Model Unico 2100, China) at 645 and 663 nm (Arnon, 1949). The content of leaf total soluble sugars was mea­ sured according to the anthrone method (Irigoyen et al., 1992). For this purpose, 0.1 g of dried leaves was extracted with 1 ml of ethanol. Leaf sampling was performed at 10:00 AM. Total phenols, total flavonoids, and free radical scav‐ enging capacity (FRSC) Fresh leaves (1 g) were homogenized in methanol for 24 h and then centrifuged at 6000 rpm for 15 min. The Folin­Ciocalteu method was used to mea­ sure the total phenolic content (Singleton and Rossi, 1965). Total flavonoids were determined based on the method of Yoo et al. (2008). The FRSC was deter­ mined using the method reported by Koleva et al. (2002) and calculated according to the formula: FRSC= 1 – A Sample (517 nm)/A Control (517 nm) ×100 Data analysis The JMP 13 statistical software (SAS Campus, Cary, NC, USA) was subjected to analysis of variance of the data. The means were separated by the least significant difference (LSD) test at the 5% significance level. 3. Results Growth attributes The results demonstrated that the plant growth traits were significantly affected by increasing the Adv. Hort. Sci., 2022 36(2): 145­153 148 salinity of irrigation water. The lowest plant height, leaf number, leaf length, and leaf width values were recorded in the S6 treated plants by 62%, 41%, 44%, and 46% decrease compared to the control, respec­ tively (Table 2). Salt stress affected the root length of S. lavandulifolia plants. Increasing salinity to S3 level had no significant effect on the root length, but its amount decreased with increasing salinity to S6 level (Table 2). Biomass production was significantly influ­ enced by salt treatments. Increasing salt stress to S2 level had no significant effect on the root dry weight. However, with increasing salinity to S6 level, its val­ ues significantly decreased (Table 2). All salinity lev­ els significantly reduced the shoot dry weight, and the lowest value was obtained from S6 treated plants with an 82% decrease compared to the control (Table 2). With increasing salt levels, total dry weight decreased significantly. Treatment of S. lavandulia plants with S6 decreased total dry weight by 78% compared to the control (Table 2). Salinity stress sig­ nificantly affected shoot/root dry weight ratio of S. lavandulifolia plants. The highest and the lowest val­ ues of shoot/root dry weight ratio were obtained from the S4 and S6 treated plants, respectively. The leaf RWC and EL Salinity stress decreased the leaf RWC of S. lavan‐ dulifolia plants. The lowest leaf RWC was achieved in S6 treated plants by a 68% decrease compared to the control (Fig. 1A). The leaf EL significantly increased with increasing salinity stress levels. The lowest (19.34%) and the highest (86.15%) leaf El values were obtained from the S0 and S6 treated plants, respec­ tively (Fig. 1B). Chlorophyll content and total soluble sugars The salinity effect was significant on the content of photosynthetic pigments. Treatment of S. lavan‐ dulifolia plants with the highest salinity level (S6) Table 2 ­ Effects of different levels of irrigation water salinity on the plant height, number of leaves per plant, leaf length, leaf width, root length, root, shoot, and total dry weight, and shoot/root dry weight ratio of S. lavandulifolia Different letters indicate significant differences according to least significant difference (LSD) test at P<0.05. ** represent significant at 1% level of probability. Values are mean ± standard error (SE). Fig. 1 ­ Effects of salinity stress on the leaf relative water content (RWC) and electrolyte leakage (EL) in S. lavandulifolia. Different letters indicate significant differences according to least significant difference (LSD) test at P<0.05. Values are mean ± standard error (SE). Irrigation water salinity (dS m­1) Plant height (cm) Number of leave per plant Leaf length (cm) Leaf width (cm) Root length (mm) Root dry weight (g. plant­1) Shoot dry weight (g. plant­1) Total dry weight (g. plant­1) Shoot/root dry weight ratio 1.3 (S0) 9.87 ± 0.31 a 52.50 ± 1.44 ab 5.32 ± 0.04 a 2.07 ± 0.04 a 35.51 ± 2.46 a 0.328 ± 0.02 a 0.45 ± 0.01 a 0.78 ± 0.01 a 1.42 ± 0.16 bc 3.3 (S1) 7.25 ± 0.25 b 52.76 ± 2.09 ab 4.92 ± 0.04 b 1.80 ± 0.07 b 33.00 ± 1.35 a 0.291 ± 0.01 a 0.33 ±0.01 b 0.62 ± 0.01 b 1.16 ± 0.06 bcd 5.3 (S2) 6.87 ± 0.42 b 57.25 ± 1.65 a 4.45 ± 0.18 c 1.77 ± 0.02 b 32.25 ± 0.75 a 0.284 ± 0.01 a 0.29 ± 0.02 c 0.57 ± 0.03 b 1.10 ± 0.05 cd 7.3 (S3) 6.62 ± 0.23 b 48.25 ± 1.10 b 4.27 ± 0.04 c 1.55 ± 0.06 c 31.50 ± 1.19 ab 0.164 ± 0.01 b 0.25 ± 0.01 d 0.41 ± 0.04 c 1.56 ± 0.14 ab 9.3 (S4) 5.37 ± 0.12 c 36.25 ± 1.18 c 3.12 ± 0.04 d 1.21 ± 0.04 d 26.51 ± 2.17 bc 0.113 ± 0.01 cd 0.21 ± 0.008 e 0.32 ± 0.007 d 1.91 ± 0.21 a 11.3 (S5) 4.62 ± 0.31 c 32.75 ± 4.30 c 3.02 ± 0.02 d 1.17 ± 0.04 d 25.01 ± 0.70 c 0.147 ± 0.01 bc 0.17 ± 0.004 f 0.31 ± 0.01 d 1.19 ± 0.11 bcd 13.3 (S6) 3.66 ± 0.16 d 30.50 ± 0.28 c 2.95 ± 0.05 d 1.10 ± 0.05 d 23.78 ± 2.47 c 0.094 ± 0.008 d 0.08 ± 0.004 g 0.17 ± 0.009 e 0.90 ± 0.14 d Significance ** ** ** ** ** ** ** ** ** Bayat et al. ‐ Salinity effects on vegetative parameters of Salvia lavandulifolia 149 decreased the amount of chlorophyll a and b, and total chlorophyll by 57%, 53%, and 54% compared to the control, respectively (Table 3). Total soluble sug­ ars were significantly affected by salt stress. By increasing the level of salt stress, the content of total soluble sugars increased upwards. The highest total soluble sugars were achieved by S6 treated plants with a 2.8 times increase compared to the control (Table 3). Total phenols, total flavonoids, and the FRSC Irrigation with saline water significantly affected the total phenols and total flavonoids of the leaves. All the levels of salt stress increased the total phe­ nols, and the highest value was obtained in the S6 treated plants (Fig. 2A). The lowest total flavonoid content was obtained in the S1 treated plants (Fig. 2B). The FRSC was significantly increased by all the levels of salinity stress. The lowest (68.16%) and the highest (85.14%) leaf FRSC values were obtained in control and S6 treated plants, respectively (Fig. 3). 4. Discussion and Conclusions The present results demonstrated that salt stress influenced the vegetative parameters in S. lavanduli‐ folia. The negative impacts of salt stress on plant growth have been reported in Salvia hispanica (Raimondi et al., 2017), in Salvia splendens (Karimian et al., 2019), and Salvia officinalis L. (Es­sbihi et al., 2021). The decrease in growth parameters under salinity stress can be related to the reduction of soil water potential and toxicity of Na+ and Cl­ ions, which leads to a nutritional imbalance (Kasrati et al., 2014; Es­sbihi et al., 2021). Salinity stress reduces cell divi­ Fig. 2 ­ Effects of salinity stress on the leaf total phenolic and fla­ vonoid content in S. lavandulifolia. Different letters indi­ cate significant differences according to least significant difference (LSD) test at P<0.05. Values are mean ± stan­ dard error (SE). sion and elongation, thereby reducing plant growth (Netondo et al. , 2004; Kamran et al. , 2020). Moreover, the decrease in plant growth under salini­ ty stress can be due to the reduction of photosynthe­ sis and energy reserves. Usually, in saline conditions, the leaf stomata are closed, and the photosynthesis rate decreases due to reduced gas exchange (Chaves Table 3 ­ Effects of different levels of irrigation water salinity on the chlorophyll a, chlorophyll b, total chlorophyll, and total soluble sug­ ars in S. lavandulifolia Different letters indicate significant differences according to least significant difference (LSD) test at P<0.05. **= represent significant at 1% level of probability. Values are mean ± standard error (SE). Irrigation water salinity (dS m­1) Chlorophyll a (mg. g FW­1) Chlorophyll b (mg. g FW­1) Total chlorophyll (mg. g FW­1) Total soluble sugars (mg. g DW­1) 1.3 (S0) 1.14 ± 0.05 a 0.58 ± 0.04 a 1.71 ± 0.09 a 7.62 ± 0.55 d 3.3 (S1) 0.79 ± 0.04 b 0.41 ± 0.03 b 1.21 ± 0.06 b 8.33 ± 0.91 d 5.3 (S2) 0.70 ± 0.05 bc 0.33 ± 0.01 bc 1.00 ± 0.04 cd 10.39 ± 1.11 cd 7.3 (S3) 0.70 ± 0.02 bc 0.35 ± 0.02 bc 1.05 ± 0.06 bc 11.69 ± 1.37 bc 9.3 (S4) 0.64 ± 0.03 c 0.30 ± 0.05 c 0.94 ± 0.06 cde 12.85 ± 0.48 bc 11.3 (S5) 0.51 ± 0.04 d 0.30 ± 0.03 c 0.79 ± 0.05 de 13.84 ± 0.85 b 13.3 (S6) 0.49 ± 0.01 d 0.27 ± 0.01 c 0.78 ± 0.11 e 21.61 ± 1.39 a Significance ** ** ** ** 150 Adv. Hort. Sci., 2022 36(2): 145­153 et al., 2009). Salinity can also inhibit root growth, thereby reducing the absorption and transport capacity of water to the shoot (Acosta­Motos et al., 2017). Irrigation with saline water decreased the RWC of S. lavandulifolia leaves (except S1). The leaf RWC is commonly used to estimate the water status of plants under stress conditions (Parida and Das, 2005). Salinity decreases the leaf RWC due to a reduced availability of water from the soil solution as a result of lowered osmotic potential triggered by the toxic effects of the Na+ and Cl­ ions (Munns, 2005; Álvarez et al., 2012; Bayat et al., 2012). In this study, the EL increased with increasing salinity levels (except S1). Increased leaf EL under salinity stress has been reported in different crops (Bayat et al., 2013; Hniličková et al., 2019; Karimian et al., 2019). Electrolyte leakage is one of the stan­ dard parameters for examining salinity tolerance in plants. Salinity stress causes inefficiency of the leaf cell membrane and consequently increases mem­ brane permeability for ions (Zhao et al., 2020). In this experiment, the content of chlorophylls decreased with increasing salinity stress levels. Reduced leaf chlorophyll content under salt stress conditions has been reported in various crops (Taïbi et al., 2016; Rahneshan et al., 2018; Es­sbihi et al., 2021). Valifard et al. (2019) reported that photosyn­ thetic pigments in Salvia mirzayanii leaves were decreased by increasing salinity stress. The decrease in chlorophyll content may be related to the toxicity effects of Na+ and Cl­ ions, which prevent the forma­ tion of pigments (Yang et al., 2011). Decreased pho­ tosynthetic pigments under salinity stress can be mainly due to the destruction of their structure with the ROS and inhibition of biosynthesis of new chloro­ phylls (Ashraf, 2003; Yang et al., 2020). In this study, irrigation with saline water enhanced the content of leaf total soluble sugars in S. lavandulifolia. Accumulation of leaf soluble sugars under salinity stress has been reported in sunflower (Zheng et al. , 2010), in Salvia miltiorrhiza L. (Gengmao et al., 2014), and cotton (Peng et al., 2016). Karimian et al. (2019) reported that salt stress significantly increased total soluble sugars in the leaves of Salvia splendens. Increased the content of soluble sugars is an indicator for osmotic regulation under stress conditions, to maintain cell turgor and continued water influx (Mittal et al., 2012). Soluble sugars were accumulated under salinity stress and protect plants through osmotic regulation, mainte­ nance of turgor pressure, and preservation of mem­ brane and protein stability (Bayat et al., 2013; Nounjan et al., 2018). The increase in concentration of soluble sugars under stress conditions is due to the higher activity of enzymes such as phosphorylase starch and sucrose phosphate synthase (Peng et al., 2016). Salinity stress significantly affected the total phe­ nols, total flavonoids, and the FRSC of S. lavandulifo‐ lia leaves. Various studies have reported the incre­ ment in total phenols, total flavonoids, and the FRSC in response to salt stress (Karimian et al., 2019; Sirin and Aslım, 2019). Valifard et al. (2014) reported the total phenols and antioxidant activity in Salvia mirza‐ yanii were increased by salinity stress. Salt stress causes the production of ROS, which damages pro­ teins, lipids, and nucleic acids (Foyer, 2018). Plants use antioxidant defense systems to scavenge and detoxify these compounds from the cell surface, which leads to increased plant antioxidant activity (Rezayian et al., 2018; Bayat and Moghadam, 2019). Phenols and flavonoids are secondary metabolites that act as potent antioxidants against oxidative stress. These non­enzymatic antioxidants protect plants by increasing their osmotic potential and thereby avoiding the dehydration of cells or regulat­ ing the redox potential, and depleting the ROS (Bautista et al., 2016; Yan et al., 2017). Although the effect of salinity stress on some species of Salvia has been studied, so far no research has been done on S. lavandulifolia species. The results demonstrated that salt stress had adverse effects on the growth parameters, photosynthetic pigments, Fig. 3 ­ Effects of salinity stress on the leaf free radical scaven­ ging capacity (FRSC) in S. lavandulifolia. Different letters indicate significant differences according to least signifi­ cant difference (LSD) test at P < 0.05. Values are mean ± standard error (SE). Bayat et al. ‐ Salinity effects on vegetative parameters of Salvia lavandulifolia 151 and cell membrane stability of the S. lavandulifolia plant. However, the total phenolic content and antioxidant activity of the leaves were increased under salinity stress conditions. In general, S. lavan‐ dulifolia can be classified as a species­sensitive plant. However, further experiments are needed to investi­ gate other mechanisms of salt stress tolerance. 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