Impaginato 149 Adv. Hort. Sci., 2025 39(2): 149­162 DOI: 10.36253/ahsc­16803 https://oaj.fupress.net/index.php/ahs Physiological tolerance of shallot varieties to airborne salinity in coastal sandy soils Saparso 1 (*), A. Sudarmaji 1, M. Bachtiar Musthafa 1, E. Wukir Tini 1, F. Pramana Putra 2, R. Raditya Kurniawan 1 1 Agrotechnology Department, Agriculture Faculty, Universitas Jenderal Soedirman, Jl. Dr. Soeparno No. 63, Purwokerto 53122, Central Java, Indonesia. 2 Agriculture Department, Faculty of Animal and Agricultural Sciences, Universitas Diponegoro, Jl. Prof. Sudarto No. 13, Semarang 50275, Cental Java, Indonesia. Key words: Resistant varieties, salinity tolerance index, seasonal shoreline wind. Abstract: Shallot as a horticultural crop has various benefits and important uses as a provider of nutritional needs. Its uniqueness in aroma and flavor makes it commonly used as a seasoning so that it has a good economic value as an increase in farmers’ income. Sandy land on the coast has the potential for shallot cultivation. The presence of wind that airborne salinity on coastal land requires the selection of tolerant varieties and knowledge of the level of airborne salinity concentration that shallot plants can tolerate. Experiments have been conducted from July to December 2023 in the screenhouse and horticultural agronomy lab, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto (7°24’27.7”S, 109°15’19.1”E). Treatments consisted of the use of shallot varieties Bali Karet (B1) and Bima Brebes (B2), with the application of several concentrations of airborne salinity consisting of 0, 6, 12, and 18 mS cm­1. The Bali Karet variety excels in plant height and root dry weight morphologically. Physiologically, Bima Brebes has higher levels of chlorophyll a and stomatal density, while Bali Karet is superior in chlorophyll b. Harvest results show Bima Brebes produces more tubers, while Bali Karet produces higher fresh tuber weight per clump. Morphological parameters (plant height, root dry weight), physiology (chlorophyll a, chlorophyll b, stomatal aperture, stomatal density), and yield showed the highest value at the lowest air salinity concentration (0 mS cm­¹). Both varieties increased proline as a tolerance mechanism to 18 mS cm­¹ air salinity. The best interaction occurred between Bali Karet and 0 mS cm­¹ salinity on stomatal opening, and between Bima Brebes and 0 mS cm­¹ salinity on stomatal density. Both varieties were classified as having moderate tolerance to 18 mS cm­¹ salinity, but total chlorophyll was very sensitive to this salinity concentration. 1. Introduction Horticultural crops play an important role in providing food nutrition (*) Corresponding author: saparso@unsoed.ac.id Citation: SAPARSO, SUDARMAJI A., BACHTIAR MUSTHAFA M., WUKIR TINI E., PRAMANA PUTRA F., RADITYA KURNIAWAN R., 2025 ­ Physiological tolerance of shallot varieties to airborne salinity in coastal sandy soils. ­ Adv. Hort. Sci., 39(2): 149­162. ORCID: S: 0000­0002­4289­6920 SA: 0000­0002­3068­7996 BMM: 0000­0002­9658­3401 WTE: 0000­0001­5122­5507 PPF: 0000­0001­6778­0775 RKR: 0009­0007­0174­7738 Copyright: © 2025 Saparso, Sudarmaji A., Bachtiar Musthafa M., Wukir Tini E., Pramana Putra F., Raditya Kurniawan R. This is an open access, peer reviewed article published by Firenze University Press (https://www.fupress.com) and distributed, except where otherwise noted, under the terms of CC BY 4.0 License for content and CC0 1.0 Universal for metadata. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no conflict of interests. Received for publication 15 November 2024 Accepted for publication 9 June 2025 AHS Advances in Horticultural Science AHS ­ Firenze University Press ISSN 1592­1573 (on line) ­ 0394­6169 (print) http://doi.org/10.36253/ahsc-16803 http://oaj.fupress.net/index.php/ahs http://orcid.org/0000-0002-4289-6920 http://orcid.org/0000-0002-3068-7996 http://orcid.org/0000-0002-9658-3401 http://orcid.org/0000-0001-5122-5507 http://orcid.org/0000-0001-6778-0775 http://orcid.org/0009-0007-0174-7738 http://www.fupress.com http://creativecommons.org/licenses/by/4.0/legalcode http://creativecommons.org/publicdomain/zero/1.0/legalcode Adv. Hort. Sci., 2025 39(2): 149­162 150 as well as increasing farmers income. Horticultural development continues as technology advances. Horticultural products are an important source of valuable nutritional and nutraceutical compounds as nutrients needed by humans (Durazzo and Lucarini, 2022). Horticultural crops include fruit plants, medicinal plants, vegetable plants, plantation plants, spices, and ornamental plants, playing an important role in the economic development and prosperity of a country (Kour et al . , 2022). The export of horticultural crop commodities provides a great opportunity globally in increasing the country’s income and the welfare of farmers. One of the potential commodities in horticultural production activities is shallots. Shallot (Allium ascalonicum L.) as a commodity type of horticulture with high economic potential for farmers’ income. Shallot cultivation plays an important role in the national economy and globally. There is a high market demand for shallots domestically and internationally, increased production and technological development are required, contributing to food security. Shallot production reached 1.985 million tons in 2023, marking a 0.14% increase (2.87 thousand tons) compared to 2022. Household consumption of shallots in 2023 decreased by 4.07% (33.83 thousand tons), totaling 797.32 thousand tons compared to the previous year. The import value of shallot in 2023 reached US $1.82 million, increased of 21.94% (US $327.46 thousand) from 2022. The consumption needs of shallots by households in Indonesia have fluctuated in the last five years, respectively in 2019 by 750.63 thousand tons; 2020 by 729.82 thousand tons; 2021 by 790.63; 2022 by 831.14 thousand tons; and 2023 by 797.32 thousand tons (Badan Pusat Statistik, 2024). Based on the high interest and potential, a strategy is needed to increase shallot productivity. As an archipelago, Indonesia has many islands spread across its territory. Indonesia as an archipelago consists of 17,504 islands, has a coastal area of 95,118 kilometers (Syamsuddin et al., 2019). The amount of sandy beach land is a potential in increasing agricultural land for farmers. Sand land is one of the potentials to overcome the problem of agricultural land conversion, as well as in horticultural development (Fikri, 2021). Seeing the increasingly limited cultivation land provides a highlight of the potential of coastal land as a feasible marginal land utilization effort. Extensification activities on coastal land can significantly increase the total shallot planting area, thereby increasing total production in an area. One of the efforts to meet shallot production needs is done with off season cultivation (Susanawati and Fauzan, 2019). Off season shallot cultivation can be done on coastal sand land (Fauzan, 2020). Different soil and climatic conditions make coastal land a challenge in conducting shallot cultivation activities. However, coastal sand land is easy to cultivate because of its loose texture so that it can save time and cost of land treatment and land is relatively safe from disease (Iriani, 2013). Another major problem that needs to be considered in cultivation on coastal land is the presence of airborne salinity. A simple sensor exposure method with a wet sponge in coastal areas showed air salinity of 19.69 mS at 6 hours and 151.19 mS at 24 hours (Saparso et al., 2023). This shows that the air salinity in coastal areas is very high as indicated by the salt particles captured on the wet sponge. Evaporation that occurs in the sea around the coast causes salt particles to be carried into the atmosphere. Winds in coastal areas carry water vapor that has a certain level of salinity originating from the sea area. When carried inland on agricultural land, water vapor with a certain level of salinity can affect plants. Deposition of salt particles on the surface of leaves and other organs, allowing uptake by plants. Growth reduction due to high salinity results from a combination of osmotic stress causing water deficit and the impact of excess Na⁺ and Cl­ ions on crucial biochemical processes (Munns and Tester, 2008). NaCl in high concentrations is toxic when accumulated in plant tissues. High concentrations of Na⁺ disrupt the uptake of K⁺ and Ca²⁺ nutrients, while high concentrations of Cl ­ decrease photosynthetic capacity due to chlorophyll degradation (Tavakkoli et al . , 2010). Salinity stress in plants influences numerous cellular mechanisms, such as disturbing cellular homeostasis, hindering photosynthesis, affecting mRNA processing, transcription, and protein synthesis, as well as disrupting energy metabolism, amino acid biosynthesis, and lipid metabolism (Hameed et al., 2021). Salinity stress can cause a reduction in photosynthesis efficiency, chlorophyll, total protein, biomass, stomatal closure and increasing the oxidative stress (Gupta and Huang, 2014). Salinity stress in plants increases the production Saparso et al. ‐ Tolerance shallot variety on airborne salinity 151 aims to determine the impact of airborne salinity on the morphology, physiology, and yield of shallot plants in two different varieties on coastal land. 2. Materials and Methods Experimental design Experiments have been conducted from July to December 2023 in the screenhouse and horticultural agronomy lab, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto (7°24’27.7”S, 109°15’19.1”E). Screenhouse microclimate with daytime peaks of 33.17°C (36,7% RH) under solar radiation and nighttime lows of 27.03°C (55,74% RH) due to radiative cooling. Experiment with factorial research with a two­ factor completely randomized design (CRD) instrument. The first factor shallot varieties consisted of Karet Bali (B1) and Bima Brebes (B2), the second factor airborne salinity at a concentration of 0 mS cm­ 1 (A0), 6 mS cm­1 (A1), 12 mS cm­1 (A2), and 18 mS cm­1 (A3). There were 8 treatment combinations with 3 replications, there are 24 units, with 5 polybags each, making a total of 120 polybags. Plant material The shallot variety Bima Brebes originates from Brebes. The plant starts flowering in 50 days and can be harvested in 60 days. It reaches 34.5 cm in height and produces 7­12 bulbs per clump. The leaves are green, cylindrical, and 14­50 in number. Dry tuber production reaches 9.9 tons per hectare. This variety is quite resistant to tuber rot but susceptible to leaf tip rot. The tubers are oval and pink in color, suitable for lowlands (Annex to the Regulation of the Indonesian Minister of Agriculture Number: 594/Kpts/TP.240/8/1984 Dated: August 11, 1984). The Bali Karet (Batu Ijo) variety of shallots originates from Batu, Malang. Plants start flowering in 45­50 days and are harvested in 55­60 days in the lowlands or 65­70 days in the highlands. It is between 45­60 cm tall and produces 2­6 bulbs per clump. The leaves are dark green, cylindrical, and number 45­50. The dry tuber production reaches 18.5 tons per hectare. The tubers are round and pink in color, and this variety is well adapted to areas with an altitude of 50­1000 meters above sea level (Annex to the Regulation of the Indonesian Minister of Agriculture Number: 366/Kpts/LB.240/6/2004 Dated: June 2, 2004). of reactive oxygen species (ROS) through oxidative stress mechanisms. ROS are normal products of cell metabolism, but environmental stress increases their production excessively, damaging biomolecules and organelles. The role of ROS as signals or stressors is determined by the balance between their formation and elimination by the antioxidant system, and disruption of this balance leads to oxidative stress (Hasanuzzaman et al., 2021). Due to the presence of high salinity there is a water deficit and an increase in free radicals that damage cell structures, plants respond by synthesizing osmolytes such as proline and sugar. Proline has antioxidant activity, activates the detoxification system, contributes to cellular homeostasis by protecting redox balance, and serves as a protein precursor and energy source in the recovery process from stress (Mansour and Ali, 2017). Proline is able to minimize damage from ROS thereby reducing lipid peroxidation, which results in protection of the photosynthetic apparatus in various plant species (Ashraf and Foolad, 2007; Wani et al., 2012). Each crop variety has a different genetic makeup that determines its adaptability to environmental stress, such as salinity. Research shows that Allium species, including shallots, are plants that are quite sensitive to salinity stress (Kadayifci et al., 2005; Kiremit and Arslan, 2016). To investigate the effect of salinity on shallot, two different varieties were used: Bima Brebes and Bali Karet. Genetic differences in shallots of Bima Brebes and Bali Karet varieties cause differences in morphology, physiology, and yield in plants. Alavan et al. (2015), stated that different varieties affect the diversity of plant appearance, due to differences in plant traits (genetic) or environmental influences. The results of research by Karo and Manik (2020), showed that differences in shallot varieties had a significant effect on the number of flowers with the highest value being the Pancasona variety 2.93 stalks and the lowest Birma 0.07 stalks. According to Azmi et al. (2011), that several varieties planted on the same land have different bulb sizes for each variety. To improve productivity on land with exposure to airborne salinity, it is necessary to select varieties that can adapt to salinity exposure. This selection of plant varieties is based on morphological, physiological and molecular markers (Soltabayeva et al., 2021). Currently, there is still no information and research on the impact of airborne salinity on shallots grown on the coast. Therefore, this study Adv. Hort. Sci., 2025 39(2): 149­162 152 Agronomic variables Plant height (cm) was determined from the soil surface to the uppermost shoot. The roots were dried in an air­circulated oven at a constant temperature of 70°C until constant weight (72 hours). Root dry weight was then weighed using an analytical balance with an accuracy of 0.01 g and expressed in grams (g) per plant. Counting the number of tubers per clump was done at harvest time. Uniform and healthy sample plants were uprooted along with the tubers. After being cleared of soil, the clumps of tubers were manually separated from the remains of dried roots and leaves. Each bulb in a clump was counted manually, and the results were expressed as the number of bulbs per clump (bulbs per clump). Fresh bulb weight per clump was measured at harvest. Each whole clump was directly weighed using an analytical balance (accuracy 0.01 g). Measurement results were expressed in grams per clump (g). Assessment of leaf greenness Data on the greenness value of shallot leaves were observed in the late vegetative and late generative phases 34 and 47 days after planting, respectively. Leaf greenness value was determined with the SP3 leaf chlorophyll meter on the SPAD­502 plus device. Data on chlorophyll content in the leaves were taken randomly in the sample unit. The leaf greenness each leaf sample observed was then taken as the average value. The results of the average value of SPAD­502 plus as sample data are processed. Data collection in sunny weather to increase the accuracy of data collection. Assessment of chlorophyll content Chlorophyll concentration was determined using the modified International Rice Research Institute (IRRI) method (Alsuhendra, 2004). A total of 0.01 g of shallot leaves were weighed on a balance sheet, pulverized in a mortar with the addition of 10 ml of 80% acetone. Leaves that have been pulverized, filtered with filter paper. The shallot leaf extract was analyzed for chlorophyll content on a spectrophotometer, 663 and 645 nm wavelengths. Chl Content (mg L­1) = (20.2 x A645) + (8.02 x A663) (1) A663 = Absorbance at 663 nm wavelength A645 = Absorbance at 645 nm wavelength Assessment of stomatal characteristics Stomatal opening was quantified by identifying epidermal impressions which were obtained from the abaxial leaf surface using clear nail polish. After application, transparent adhesive tape was pressed onto the coated section and carefully peeled to transfer the imprint. The tape­mounted impression was then affixed to a glass slide for stomatal aperture observation at 400× magnification. Imprints were examined under a compound light microscope equipped with a calibrated ocular micrometer. Stomatal opening width (μm) was measured as the maximum pore distance between guard cells. Stomatal density was quantified by counting stomata within a defined microscopic field of view (area = 0.1589 mm² at 400× magnification). The density was calculated using the formula: Density = Number of stomata/Field of view area Proline content determination Proline (μmol g­1 fresh weight) was determined based on the technique (Bates et al., 1973), in 0.5 g fresh leaves that have been mashed given 10 mL of 3% 5­sulfosalicylic acid, then filtered. The filtrate was then given 2 mL ninhydrin (2,2­dihydroxyindane­1,3­ dione) and 2 mL glacial acetic acid, put in a tube, for one hour heated at 100°C (212.0°F) with the addition of 4 mL toluene. The extract solution turned dark red indicating proline content, measured by Milton Roy 2D Spectrophotometer, wavelength 520 nm. The value on the spectrophotometer was calculated by the formula: Proline content (μmol g­1 fresh weight) = (64.3649 x absorbance) + (­5.2987 x 0.347) (2) 64.3649 = The slope value of the standard curve, which indicates the increase in proline content (μmol g­¹) per unit increase in absorbance. Absorbance = Spectrophotometric measurement value that is directly proportional to the concentration of proline in the sample. Assessment of stress tolerance index (STI) The stress tolerance index (STI) quantifies shallot yield under salinity stress relative to yield under normal conditions. This index was calculated using the formula established by Hooshmandi (2019): STI = (Hp × Hs) / (H ̄p)² (3) where STI is stress tolerance index, Hp= Yield of a genotype under non­stressed conditions, Hs the yield Saparso et al. ‐ Tolerance shallot variety on airborne salinity 153 of a genotype under stressed conditions, and H ̄p is Mean yield of all genotypes under non­stressed conditions. Data analysis Analysis of variance (ANOVA), was used in data analysis. Duncan’s Multiple Range Test (DMRT) was then used on data significantly different at 5% standard error. Statistical data were processed using SPSS 26 supported by Microsoft Excel. 3. Results The results show that salinity in several levels affects the morphological variables of shallots (Table 1, Fig. 1) . Plant height and root dry weight of shallots of Bali Karet varieties are 58.53 cm and 0.11 g plant­1 higher than Bima Brebes by 20.16% and 120%. While the leaf greenness of both varieties is not significantly different. Bali Karet variety is higher than Bima Brebes in all morphological parameters, indicating it is more tolerant to salinity stress. Airborne salinity treatment significantly reduces plant height, leaf greenness, and root dry weight variables with the highest values of 57.69 cm; 48.16; Table 1 ­ Varietal effect and air salinity on shallot morphology Data are expressed as the mean of determination ± SD in 3 replicates. Means followed by the same letter in one column are not significantly different (p<0.05). Treatment Plant height (cm) Leaf greenness Root dry weight (g plant­1) Varieties (B) Bali Karet (B1) 58.53±2.55 a 43.67±6.24 a 0.11±0.06 a Bima Brebes (B2) 48.71±4.68 b 44.18±3.36 a 0.05±0.01 b Airborne salinity (A) 0 mS cm­1 (A0) 57.69±5.18 a 48.16±2.43 a 0.12±0.08 a 6 mS cm­1 (A1) 53.98±6.01 ab 45.00±4.17 ab 0.08±0.03 ab 12 mS cm­1 (A2) 52.81±6.06 b 42.93±4.26 bc 0.08±0.04 ab 18 mS cm­1 (A3) 49.99±6.49 b 39.57±4.71 c 0.06±0.03 b Varieties (B) x Airborne salinity (A) B1A0 61.01±2.44 a 49.00±2.86 a 0.18±0.08 a B1A1 59.30±1.60 ab 45.45±5.23 abc 0.10±0.03 b B1A2 58.03±2.15 ab 42.53±5.96 bcd 0.10±0.04 b B1A3 55.80±1.05 b 37.68±6.34 d 0.09±0.03 b B2A0 54.37±5.30 b 47.34±2.35 ab 0.06±0.02 b B2A1 48.68±1.76 c 44.56±3.93 abc 0.06±0.01 b B2A2 47.60±2.34 c 43.34±3.06 bcd 0.06±0.02 b B2A3 44.19±1.75 c 41.47±2.16 cd 0.05±0.00 b Fig. 1 ­ Effects of using different varieties (B1= Bali Karet, B2= Bima Brebes) on plant height (A) and root dry weight (B). Data are expressed as the mean of determination ± SD in 3 replicates. 154 Adv. Hort. Sci., 2025 39(2): 149­162 and 0.12 g plant­1 at 0 mS cm­1 (A0), respectively, with differences reaching 15.40%; 21.71%; and 100% at 18 mS cm­1 (A3). The analysis of two shallot varieties at several levels of airborne salinity shows that Bali Karet and Bima Brebes varieties are slightly tolerant to airborne salinity and both have the same decreasing trend in morphology (plant height, leaf greenness, and root dry weight) as airborne salinity increases (Fig. 2); however, both varieties have different mechanisms to salinity stress. In Table 2 and figure 3 can be observed that the shallot variety Bima Brebes has a value of 9.33 mg L­1 13.69% greater than the value of chlorophyll a Bali Karet. In contrast, the Bali Karet variety has values of 6.85 mg L­1 and 16.19 mg L­1 respectively 86.14% and 11.58% greater than the chlorophyll b and total values of Bima Brebes. Physiological characteristics were significantly affected by the level of airborne salinity in chlorophyll a, b, and total variables (Fig. 4) with the highest values of 12.28 mg L­1; 8.54 mg L­1; and 20.83 mg L­1 at 0 mS cm­1 (A0), these values were 57.44%; 288.18%; and 108.09% higher than the 18 mS cm­1 treatment (A3). Considering the results of the two varieties under escalating airborne salinity, Bali Karet and Bima Brebes deploy contrasting chlorophyll strategies. Bali Karet boosts chlorophyll b to maximize light harvesting for growth, while Bima Brebes prioritizes chlorophyll a to protect Fig. 2 ­ Effects of airborne salinity (0, 6, 12, and 18 mS) on plant height (A), leaf greenness (B), and root dry weight (C). Data are expressed as the mean of determination ± SD in 3 replicates. Table 2 ­ Varietal effect and air salinity on shallot physiology (chlorophyll) Data are expressed as the mean of determination ± SD in 3 replicates. Means followed by the same letter in one column are not significantly different (p<0.05). Treatments Chlorophyll a (mg L­1) Chlorophyll b (mg L­1) Total chlorophyll (mg L­1) Varieties (B) Bali Karet (B1) 9.33±2.35 b 6.85±4.52 a 16.19±5.13 a Bima Brebes (B2) 10.81±2.61 a 3.68±2.58 b 14.51±4.40 a Airborne salinity (A) 0 mS cm­1 (A0) 12.28±2.33 a 8.54±4.22 a 20.83±2.70 a 6 mS cm­1 (A1) 10.88±1.66 ab 5.54±3.76 ab 16.43±2.56 b 12 mS cm­1 (A2) 9.32±1.41 bc 4.78±3.63 ab 14.12±3.19 bc 18 mS cm­1 (A3) 7.80±2.47 c 2.20±1.40 b 10.01±2.54 c Varieties (B) x Airborne salinity (A) B1A0 10.88±2.49 bc 11.13±2.50 a 22.01±1.20 a B1A1 10.25±1.88 bcd 7.04±5.30 b 17.29±3.49 bc B1A2 8.71±1.65 bcd 6.17±5.19 b 14.89±4.63 cd B1A3 7.50±2.71 d 3.07±1.19 bc 10.58±2.74 de B2A0 13.68±1.22 a 5.97±4.27 b 19.65±3.56 ab B2A1 11.52±1.47 ab 4.05±0.69 bc 15.57±1.44 bc B2A2 9.94±1.07 bcd 3.40±0.54 bc 13.35±1.47 cde B2A3 8.11±2.75 cd 1.34±1.11 c 9.45±2.76 e Saparso et al. ‐ Tolerance shallot variety on airborne salinity 155 photosynthetic reaction centers. This reflects a fundamental trade­off between photon capture (Bali Karet) and photochemical resilience (Bima Brebes), a divergence critical for variety­specific airborne salinity adaptation. Table 3 shows that the use of different varieties on stomatal physiology impacts only density of stomata, with the variety of Bima Brebes having a stomatal density of 55.55 stomatal mm­2 greater 17.79% than the variety of Bali Karet. No significant differences are found on stomatal opening and proline content. Nevertheless, it can be noticed that Bali Karet variety has a value of 3.58 µm 4.68% greater than Bima Brebes on stomatal opening, and that Bali Karet variety has a value of 1.15 μmol g­1 fresh weight 19.01% lower than Bima Brebes on proline content. Several treatments at the airborne salinity level had an effect on decreasing stomatal opening and density and increasing proline. The highest value of stomal opening and stomatal density are 4.66 µm and 58.70 stomatal.mm­2 at 0 mS cm­1, 100% and 36.61% surpassed the 18 mS cm ­1 treatment. In opposite, the highest value on proline 2.24 μmol g­1 fresh weight fresh leaves at 18 mS cm­1 on proline up to 397.78% greater than the control (0 mS cm­1). In the physiological characteristics, the interaction between the use of different varieties and the level of airborne salinity influenced considerably stomatal mechanism of stomatal opening and stomatal density with the highest values of 5.33 µm and 54.50 stomatal mm­2 (B1A0), respectively 128.76% and 52.96% surpassed B1A3 and B2A3 on stomatal opening and B1A3 on stomatal density (Fig. 5). Although there was no interaction on proline between the use of two shallot varieties and airborne salinity at several levels, it can be observed that the Bima Brebes variety accumulated higher proline than Bali Karet with the same increasing trend. This shows the type of adaptation of Bima Brebes on cellular adaptation, compared to Bali Karet which focuses on growth optimization (Fig. 6). Data are expressed as the mean of determination ± SD in 3 replicates. Means followed by the same letter in one column are not significantly different (p<0.05). Table 4 shows that there is an influence of both varieties on yield characteristics, variable number of bulbs per clump Bima Brebes 6.66 pieces greater 55.61% than Bali Karet. In fresh bulb weight per clump on the contrary, Bali Karet has a value of 45.38 Fig. 3 ­ Effects of using different varieties (B1= Bali Karet, B2= Bima Brebes) on chlorophyll a (A) and chlorophyll b (B). Data are expressed as the mean of determination ± SD in 3 replicates. Fig. 4 ­ Effects of airborne salinity (0, 6, 12, and 18 mS) on chlorophyll a (A), chlorophyll b (B), total chlorophyll (C). Data are expressed as the mean of determination ± SD in 3 replicates. g, 95.09% greater than Bima Brebes. The yield parameter in the airborne salinity treatment in the research conducted had no effect. The interaction of two shallot varieties at several levels of airborne salinity was not significant on yield. Bali Karet variety Adv. Hort. Sci., 2025 39(2): 149­162 156 Fig. 5 ­ Effects of airborne salinity (0, 6, 12, and 18 mS) on stomatal opening (A), stomatal density (B), and proline (C). Data are expressed as the mean of determination ± SD in 3 replicates. Fig. 6 ­ Interaction of different varieties (B1= Bali Karet, B2= Bima Brebes) with different levels of airborne salinity (0, 6, 12, and 18 mS) on stomatal opening (A) and stomatal density (B). Data are expressed as the mean of determination ± SD in 3 replicates. Table 3 ­ Varietal effect and air salinity on shallot physiology (stomatal and proline) Data are expressed as the mean of determination ± SD in 3 replicates. Means followed by the same letter in one column are not significantly different (p<0.05). Treatment Stomatal opening (µm) Stomatal density (Stomatal mm­2) Proline (μmol g­1 fresh weight) Varieties (B) Bali Karet (B1) 3.58±1.31 a 47.16±8.69 b 1.15±0.78 a Bima Brebes (B2) 3.42±0.90 a 55.55±6.48 a 1.42±0.92 a Airborne salinity (A) 0 mS cm­1 (A0) 4.66± 0.82a 58.70±6.50 a 0.45±0.38 c 6 mS cm­1 (A1) 4.16±0.41 a 52.41±8.59 ab 0.95±0.32 bc 12 mS cm­1 (A2) 2.83±0.41 b 51.36±2.57 b 1.47±0.44 ab 18 mS cm­1 (A3) 2.33±0.52 b 42.97±8.36 c 2.24±0.87 a Varieties (B) x Airborne salinity (A) B1A0 5.33±0.58 a 54.50±3.63 abc 0.21±0.05 d B1A1 4.00±0.00 abc 46.12±7.26 c 0.91±0.33 bcd B1A2 2.66±0.58 cd 52.41±3.63 bc 1.53±0.30 abc B1A3 2.33±0.58 d 35.63±3.63 d 1.94±0.76 ab B2A0 4.00±0.00 abc 62.89±6.29 a 0.71±0.42 cd B2A1 4.33±0.58 ab 58.70±3.63 ab 1.00±0.37 bcd B2A2 3.00±0.00 bcd 50.31±0.00 bc 1.42±0.61 bc B2A3 2.33±0.58 d 50.31±0.00 bc 2.55±1.03 a Saparso et al. ‐ Tolerance shallot variety on airborne salinity 157 has an escape response shown in fresh bulb weight per clump which is higher than Bima Brebes, although Bima Brebes is higher in the number of bulbs per clump due to the defense response from airborne salinity stress (Fig. 7). Table 5 show that shallot varieties Bali Karet and Bima Brebes were medium tolerant variety (mt) on 6, 12, and 18 mS cm­1 airborne salinity. This shows the ability of both varieties to tolerate salinity stress, but have different response mechanisms. The responses of the two varieties to physiology, morphology, and yield are shown in Tables 1­4. 4. Discussion and Conclusions Salinity on certain levels can affect morphology, physiology and yield in plants. According to Shokat and Großkinsky (2019), salinity stress is one of the major problems in agriculture studied globally. Dry weight loss is one of the signs that plant growth is affected by salinity (Suharjo et al., 2021). The results in Table 1 show that the higher the airborne salinity, the lower the morphological variables in shallots. Salinity determines the ability of plants to grow because it can damage cells. High salinity levels affect water uptake by plants due to salt around the plant roots, which causes oxidative stress (Anwar et al., 2024), prolongs shoot emergence, slows leaf growth, reduces plant height, changes the form of tubers, and reduces their overall mass and size (Alam et al., 2023). Table 4 ­ Varietal effect and air salinity on shallot yield Treatment Number of bulbs per clump Fresh bulb weight per clump (g) Varieties (B) Bali Karet (B1) 4.28±0.77 b 45.38±11.15 a Bima Brebes (B2) 6.66±1.23 a 23.26±10.46 b Airborne salinity (A) 0 mS cm­1 (A0) 4.80±0.49 a 41.17±22.01 a 6 mS cm­1 (A1) 5.90±1.52 a 32.78±14.57 a 12 mS cm­1 (A2) 5.47±2.15 a 33.08±15.50 a 18 mS cm­1 (A3) 5.73±1.85 a 30.27±9.15 a Varieties (B) x Airborne salinity (A) B1A0 4.40±0.35 b 54.68±12.97 a B1A1 4.67±0.42 b 43.85±12.53 abc B1A2 3.73±1.21 b 45.49±10.19 ab B1A3 4.33±0.92 b 37.51±5.36 abcd B2A0 5.20±0.00 b 27.65±22.26 bcd B2A1 7.13±1.01 a 21.71±2.34 cd B2A2 7.20±1.06 a 20.66±5.88 d B2A3 7.13±1.36 a 23.03±4.81 cd Data are expressed as the mean of determination ± SD in 3 replicates. Means followed by the same letter in one column are not significantly different (p<0.05). Table 5 ­ Varieties effect and airborne salinity on stress tolerance index Stress Tolerance Index <0.5 sensitive variety (tt), 0.5­1.0 medium tolerant variety (mt). STI >1 tolerant variety (t) (Saparso et al., 2024). Variables Varieties Airborne salinity (mS cm­1) 6 12 18 Stress tolerance index Bali Karet 0.802 (mt) 0.832 (mt) 0.686 (mt) Bima Brebes 0.785 (mt) 0.747 (mt) 0.833 (mt) Fig. 7 ­ Effects of using different varieties (B1= Bali Karet, B2= Bima Brebes) on number of bulbs per clump (A) and fresh bulb weight per clump (B). Data are expressed as the mean of determination ± SD in 3 replicates. and 58.70 stomatal.mm­2 at 0 mS cm­1, 100% and 36.61% surpassed the 18 mS cm ­1 treatment. Accordingly, the results of research by Fakhri and Ekawati (2020), explained that different salinities had a significant effect on the chlorophyll a content in Dunaliella sp., an increase in salinity from 15 to 35 ppt caused a 32.65% decrease in chlorophyll a content with the highest concentration (11.27 mg L­1) produced at 15 ppt salinity. Salinity inhibits the osmotic uptake of water, which negatively affects the carbon assimilation process, salinity decreases photosynthetic rate, transpiration, stomatal conductance and chlorophyll levels in plants, affecting the ability of plants to photosynthesize optimally (Ashraf and Ali, 2008). Salinity stress lowers the osmotic potential of the soil solution reducing the availability of water for plants and increasing the concentration of ions that are toxic to plants (Anugrah et al., 2022). Plants have mechanisms to deal with stress. Exposed to salinity stress on plants, stomatal will be closed to protect against water loss, leading to increased leaf temperature, salinity­ induced stress resulting in stomatal regulation, with strategies to cope with ionic and osmotic pressures induced by NaCl (Orzechowska et al., 2021). Accumulations of cytotoxic­dependent toxic ions such as Na+ and Cl­ and formation of reactive oxygen species (ROS), can occur due to salinity stress disrupting plant development and growth through water stress (Isayenkov, 2012). Under conditions of oxidative stress, changes in cell metabolic processes occur, causing the production of ROS to increase excessively, damaging proteins, fats, nucleic acids, and can cause plant cell death (Ahmad et al., 2019). Plants activate antioxidants (SOD, CAT) and accumulate compatible solutes (proline, glycine betaine) for mitigation (Hasegawa et al., 2000). According to the research Saparso et al. (2023), higher proline content makes plants more tolerant of air salinity stress, proline content in the plant increases the higher the level of air salinity applied, where the highest proline content of corn plants treatment of 18 mS air salinity, which is 3.58 μmol g­1 and the lowest proline content in the treatment of 0 mS air salinity, which is 1.75 μmol g ­1. This is consistent with the results of this study, that increased exposure to airborne salinity increases proline levels. The proline functions as an osmolyte helping to maintain osmotic balance in plant cells, at high salinity water tends to escape from cells due to differences in ion concentration, the presence, Adv. Hort. Sci., 2025 39(2): 149­162 158 This research found that higher airborne salinity reduced morphological characteristics such as plant height, leaf greenness, and root dry weight. Those effects may be explained by the fact that saline environments generally have the same or even higher osmotic pressure than in plant cells, which can inhibit water from entering plant cells. Water flows from areas of low osmotic pressure to areas of higher osmotic pressure, causing plants in saline conditions to experience water stress. In Allium cepa, stress inhibits cell division so that the number of new cells is reduced and the meristem shrinks in size (Kielkowska, 2017). Osmotic pressure also affects the speed at which cells absorb nutrients (Zainuddin et al., 2017). Compared to the control, root fresh weight in pomegranate cultivars decreased by 46.3%, 57.4%, and 66% under 6, 9, and 12 dS m⁻ ¹ salinity treatments, respectively, while root dry weight decreased by 45.4%, 52.5%, and 59% at the same salinity levels (Jadidi et al., 2020). Salinity stress significantly reduced pepper plant height (Badem and Söylemez, 2022), leaf greenness values were lower under higher NaCl stress (Rustikawati et al., 2023). According to research by Kul et al. (2021), water salinity caused 22.0% decrease in root fresh weight and 36.0% decrease in root dry weight of tomato compared to non­saline control and unamended control. Plants have evolved biochemical and molecular mechanisms, which work in sync as an integrated physiological response to soil salinity (Ruiz­Lozano et al., 2012). High salinity reduces crop production, subsequent growth, and cause physiological defects threatening global food security and prosperity (Balasubramaniam et al., 2023). Furthermore, high salinity environments can damage plant membranes and chlorophyll in Zea mays and Cyperus rotundus, causing disturbances in nutrient absorption due to disturbed ion balance in plant roots (Pranasari et al., 2012). The accumulation of Na⁺ and Cl­ in tissues disrupts enzyme function, photosynthesis, and cell division, especially in young leaves (Munns and Tester, 2008). Other responses in plants include selective buildup or exclusion of salt ions as maintenance on the photosynthesis process to reach adequate values for plant growth, changes in membrane structure, and phytohormone synthesis (Türkan and Demiral, 2009). The present study shows that as increasing airborne salinity from 0 to 18 mS cm­1 decreased total chlorophyll by 20.83, 16.43, 14.12, 10.01 mg L­1 recpectively. The highest value of stomal opening and stomatal density are 4.66 µm Saparso et al. ‐ Tolerance shallot variety on airborne salinity 159 accumulation of proline so that plant cells can draw water in, prevent dehydration and maintain cell turgor. According to Khanna­Chopra et al. (2019), plants produce proline and accumulate in the cytosol, in response to stresses such as salinity, to modify the osmotic properties of the cytoplasm thereby increasing tolerance in plants. However, it is also known that proline can increase the resistance and growth ability of plants under stressful conditions, such as high salinity. Increase in proline under salinity stress as extra Nitrogen (N) and energy storage achieved through salinity­induced growth reduction for plant survival and growth under stress conditions (Kubala et al., 2015). Table 3 and 5 indicate that the increase in proline due to exposure to 6 mS cm ­1 to 18 mS cm ­1 represents the ability of both varieties to maintain cell osmoregulators so as not to cause physiological and metabolic plant stress. According to Ayub et al. (2015), high proline in plants tolerant of environmental stress plays a role in regulating plant cell osmoregulators. The defense mechanism from cell damage due to ROS as free radicals, plants respond through the antioxidant defense system (Denaxa et al., 2020). Proline plays a very important role in reducing the negative effects of plant salinity stress by neutralizing free radicals formed due to increased ROS. Plants have enzymatic and non­ enzymatic antioxidant defense systems, which play an important role in detoxifying ROS generated under stress conditions, it is known that proline acts as an enzyme protector and ROS antioxidant. (Khatun et al., 2020). According to Silva­Ortega et al. (2008), proline accumulates dominantly in leaves to maintain chlorophyll levels and cell turgor pressure, which is crucial for preserving photosynthetic productivity when facing salinity stress. Accumulation of proline in stressed plants occurs both through induction of proline bio­synthesizing gene expression (P5CR and P5CS) and by inhibition of genes associated with the degradation pathway. Under osmotic stress conditions, proline synthesis is mediated by the enzymes encoded by the P5CS and P5CR genes in most plants (Furlan et al., 2020). Salinity has three effects on crop growth and yield in the form of ion unbalance, ionic and osmotic stress (Anshori et al., 2018). However, experiment results reported in this study showed that airborne salinity had no effect on shallot production. There was a 19.38% decrease in the number of bulbs per clump in the comparison of control and 18 mS cm­1 treatment, in addition to the fresh bulb weight per clump control was 26.48% greater than 18 mS cm ­1 treatment, but both parameters were not significantly different. This is in line with research Saparso et al. (2024), in cauliflower and cabbage, unlike the physiological response, plants in the air salinity level treatment had no impact on yield. Salinity conditions affect plant nutrient uptake due to the presence of excess Na+ and Cl­ ions that prevent the uptake of NO3 ­, Ca2 +, and K+ ions respectively (Kharisun et al., 2022), the decrease may be due to the fact that these elements are very important in the initiation of bulbs (Mardhiana et al., 2018). In research, some crops showed a decrease in yield due to salinity. Tomato yield decreased by 7.2% at 5 mS cm­1 salinity and increased at higher salinities (Zhang et al., 2016). Research on Onion Granex 33 variety against 6 NaCl concentrations showed that increasing NaCl concentration resulted in a decrease in the fresh weight of mature plant bulbs, even plants could not survive at 125 mM NaCl concentration (Ratnarajah and Gnanachelvam, 2021). According to research by Syamsiyah et al. (2020), high salinity levels did not significantly affect yield components such as growth, yield, number of tubers, fresh and dry tuber weight of local shallots of Brebes and Purbalingga which varieties are tolerant of salinity up to salinity levels of 3 mS cm­1. Meanwhile, this study shows that exposure to airborne salinity at the highest level up to 18 mS cm ­1 (A3) does not significantly affect the yield of shallots Bima Brebes and Bali Karet on the variable number of bulbs per clump and fresh bulb weight per clump. In this study, it can be said that airborne salinity stress does not affect the yield of shallot varieties of Bima Brebes and Bali Karet because both varieties are tolerant and able to adapt to certain levels of salinity. This adaptability allows them to maintain physiological and morphological stability, resulting in consistent yields despite saline conditions. Bali Karet variety has an increased response on growth variables, while Bima Brebes has a response on physiological variables. The results of research by Hadianti and Damanhuri (2019), that the six varieties of shallots: Bima Brebes, Bauji, Super Philip, Tajuk, Katumi, and Trisula are tolerant of high salinity concentrations, at ppm 12,000 experiencing severe stress. Sidabariba and Sudjatmiko (2023), stated that with its advantages, the Bali Karet (Batu Ijo) variety can adapt well to its growing environment. A schematic representation of the different Adv. Hort. Sci., 2025 39(2): 149­162 160 Acknowledgements Gratitude to the Institute for Community Research and Development, Jenderal Soedirman University, which is stated in the Applied Funded Research budget contract for the fiscal period 2023. References AHMAD R., HUSSAIN S., ANJUM M.A., KHALID M.F., SAQIB M., ZAKIR I., HASSAN A., FAHAD S., AHMAD S., 2019 ­ Oxidative stress and antioxidant defense mechanisms in plants under salt stress , pp. 191­205. ­ In: HASANUZZAMAN M., K.R. HAKEEM, K. NAHAR, and H.F. ALHARBY (eds.) Plant abiotic stress tolerance: Agronomic, molecular and biotechnological approaches. Springer, Cham, Switzerland, pp. 490. ALAM M.A., RAHMAN M.A., RAHMAN M.M., HASAN M.M., NAHER S., FAHIM A.H.F., MOTTALIB A., ROY S., ISLAM R., MOZUMDER S.N., ALSUHAIBANI A.M., GABER A., HOSSAIN A., 2023 ­ Performance valuation of onion (Allium cepa L.) genotypes under different levels of salinity for the development of cultivars suitable for saline regions. ­ Front. Plant Sci., 14: 1154051. ALAVAN A., HAYATI R., HAYATI E., 2015 ­ Pengaruh pemupukan terhadap pertumbuhan beberapa varietas pad Gogo (Oryza sativa L.). ­ J. Floratek 10: 61­68. ANSHORI M.F., PURWOKO B.S., DEWI I.S., ARDIE S.W., SUWARNO W.B., SAFITRI H., 2018 ­ Determination of selection criteria for screening of rice genotypes for salinity tolerance. ­ SABRAO J. Breed. Genet., 50(3): 279­294. ANUGRAH D.E., SETIAWAN T.P., SASMITA R., AULIA E., AMININGSIH R., SARI V.N., HAJIJAH S.W., KENCANA Y.D., NUGRAHA E.D.S., SAFITRI I.K., PRATAMA J.S.A., SUHARJO U.K.J., FAHRURROZI F., 2022 ­ Penggunaan indikator fisiologis untuk menentukan tingkat cekaman salinitas pada tanaman padi (Oryza sativa L.). ­ J. Agroqua: Media Informasi Agronomi Budidaya Perairan, 20(1): 50­65. ANWAR N.H., KARYAWATI A.S., MAGHFOER M.D., KURNIAWAN A., 2024 ­ Organic fertilizer alleviates salt stress in shallot by modulating plant physiological responses. ­ J. Ecol. Engin., 25(7). ASHRAF M., ALI Q., 2008 ­ Relative membrane permeability and activities of some antioxidant enzymes as the key determinants of salt tolerance in canola (Brassica napus L.). ­ Environ. Exp. Bot., 63(1­3): 266­273. ASHRAF M., FOOLAD M.R., 2007 ­ Roles of glycine betaine and proline in improving abiotic stress resistance. ­ Environ. Exp. Bot., 59: 206­216. AYYUB C.M., ALI M., SHAHEEN M.R., QADRI R.W.K., KHAN I., JAHANGIR M.M., ABBASI K.Y., KAMAL S., ZAIN M., 2015 ­ Enhancing the salt tolerance potential of Fig. 8 ­ Effect of airborne salinity on morphology, physiology, and yield parameters in two shallot varieties. mechanisms performed by the two shallot varieties at increasing salinity levels is shown in figure 8. This study shows that both varieties are medium tolerant (mt) or tolerant (t) to 18 mS cm­1 airborne salinity for most of the parameters, except that for total chlorophyll. More in detail, the following differences in the performances of the two varieties can be highlighted, where Bali Karet and Bima Brebes are tolerant to airborne salinity, but both have different response mechanisms to airborne salinity stress. The Bali Karet variety increases the ability to optimize growth, indicating escape type adaptation with a focus on short term productivity (higher plant height and root dry weight) and bulb weight; while the Bima Brebes variety reflects cellular defense based tolerance type adaptation (higher chlorophyll a and stomatal density) and number of bulbs. Of course different level of salinity determined different responses. Interestingly, both varieties of Bali Karet and Bima Brebes show a tolerance mechanism through increased osmoregulators with an increase in proline at the highest airborne salinity concentration (18 mS cm­1). Saparso et al. ‐ Tolerance shallot variety on airborne salinity 161 watermelon (Citrullus lanatus) by exogenous application of salicylic acid. ­ Amer. J. Plant Sci., 6(19): 3267­3271. AZMI C., HIDAYAT I.M., WIGUNA G., 2011 ­ Pengaruh varietas dan ukuran umbi terhadap produktivitas bawang merah. ­ J. Hortikultura, 21(3): 206­213. BADAN PUSAT STATISTIK, 2024 ­ Statistic of horticulture 2023 (Vol. 5). ­ Badan Pusat Statistik, Jakarta. BADEM A., SÖYLEMEZ S., 2022 ­ Effects of nitric oxide and silicon application on growth and productivity of pepper under salinity stress. ­ J. King Saud Univ. ­ Sci., 34(6): 102189. BALASUBRAMANIAM T., SHEN G., ESMAEILI N., ZHANG H., 2023 ­ Plant’s response mechanisms to salinity stress. ­ Plants, 12(12): 1­22. BATES L.S., WALDREN R.P.A., TEARE I.D., 1973 ­ Rapid determination of free proline for water‐stress studies. ­ Plant Soil, 39: 205­207. DENAXA N.K., DAMVAKARIS T., ROUSSOS P.A., 2020 ­ Antioxidant defense system in young olive plants against drought stress and mitigation of adverse effects through external application of alleviating products. ­ Scientia Hortic., 259: 108812. DURAZZO A., LUCARINI M., 2022 ­ Chemical properties, nutritional quality, and bioactive components of horticulture food. ­ Horticulturae, 8(1): 3. FAKHRI M., EKAWATI A.W., 2020 ­ Pengaruh salinitas terhadap Pertumbuhan, Biomassa dan Klorofil‐a Dunaliella sp. ­ J. Fisheries Marine Res., 4(3): 393­398. FAUZAN M., 2020 ­ Pendapatan rumah tangga petani bawang merah lahan pasir pantai di Kabupaten Bantul. ‐ JAS, Jurnal Agri Sains, 4(1): 60­66. FIKRI M.R.A., 2021 ­ Faktor‐Faktor yang Mempengaruhi Peranan Kelompok Tani dalam Penerapan Inovasi Teknologi Budidaya Cabai di Lahan Pasir Pantai Kabupaten Kulon Progo. J. Agrimanex: Agribusiness, Rural Manag. Develop. Ext., 1(2): 20­27. FURLAN A.L., BIANUCCI E., GIORDANO W., CASTRO S., BECKER D.F., 2020 ­ Proline metabolic dynamics and implications in drought tolerance of peanut plants. Plant Physiol. Biochem., 151, 566­578. GUPTA B., HUANG B., 2014 ­ Mechanism of salinity tolerance in plants: Physiological, biochemical, and molecular characterization. ­ Int. J. Genomics, 2014: 701596. HADIANTI F.N., DAMANHURI D., 2019 ­ Toleransi Enam Varietas Tanaman Bawang Merah (Allium ascalonicum L.) pada Cekaman Salinitas. ­ J. Produksi Tanaman, 7(12). HAMEED A., AHMED M.Z., HUSSAIN T., AZIZ I., AHMAD N., GUL B., NIELSEN B.L., 2021 ­ Effects of salinity stress on chloroplast structure and function. ­ Cells, 10(8): 2023. HASANUZZAMAN M., RAIHAN M.R.H., MASUD A.A.C., RAHMAN K., NOWROZ F., RAHMAN M., NAKAR K., FUJITA M., 2021 ­ Regulation of reactive oxygen species and antioxidant defense in plants under salinity. ­ Inter. J. Mol. Sci., 22(17): 9326. HASEGAWA P.M., BRESSAN R.A., ZHU J.K., BOHNERT H.J., 2000 ­ Plant cellular and molecular responses to high salinity. ­ Ann. Rev. Plant Biol., 51(1): 463­499. HOOSHMANDI B., 2019 ­ Evaluation of tolerance to drought stress in wheat genotypes. ­ Idesia, 37(2): 37­ 43. IRIANI E., 2013 ­ Prospek pengembangan inovasi teknologi bawang merah di lahan sub optimal (lahan pasir) dalam upaya peningkatan pendapatan petani. ­ J. Litbang Provinsi Jawa Tengah, 11(2): 231­243. ISAYENKOV S.V., 2012 ­ Physiological and molecular aspects of salt stress in plants. ­ Cytol. Genet., 46(5): 302­318. JADIDI E., TATARI M., GHASEMNEZHAD M., SALEMI H.R., 2020 ­ The salinity tolerance of pomegranate cultivars: Effects of salt stress on root and leaf mineral content. ­ Adv. Hort. Sci., 34(3): 325­335. KADAYIFCI A., TUYLU G., UCAR Y., CAKMAK B., 2005 ­ Salt stress and Allium species. ­ J. Plant Nutr., 28(10): 1865­ 1877. KARO B.B., MANIK F., 2020 ­ Observasi dan adaptasi 10 varietas bawang merah (allium cepa) di berastagi dataran tinggi basah. ­ J. Agroteknosains, 4(2): 1­9. KHANNA­CHOPRA R., SEMWAL V.K., LAKRA N., PAREEK A., 2019 ­ Proline ‐ A key regulator conferring plant tolerance to salinity and drought, pp. 59­80. ­ In: HASANUZZAMAN M., M. FUJITA, H. OKU, and M.T. ISLAM (eds.) Plant tolerance to environmental stress. CRC Press, Boca Raton, FL, USA, pp. 488. KHARISUN, SISNO, BUDIONO M.N., ROKHMINARSI, KURNIASIH K., 2022 ­ The study of silica (Si) and salinity on the growth and yield of shallot plant (Allium ascalonicum L.) in an Entisol soil. ­ Proceedings of the 2nd Int. Conf. for Smart Agriculture, Food, and Environment (ICSAFE 2021), Atlantis Press, Dordrecht, The Netherlands, pp. 18­31. KHATUN M., MATSUSHIMA D., RHAMAN M.S., OKUMA E., NAKAMURA T., NAKAMURA Y., MUNEMASA S., MURATA Y., 2020 ­ Exogenous proline enhances antioxidant enzyme activities but does not mitigate growth inhibition by selenate stress in tobacco BY‐2 cells. ­ Biosci., Biotechol., Biochem., 84(11): 2281­2292. KIEŁKOWSKA A., 2017 ­ Allium cepa root meristem cells under osmotic (sorbitol) and salt (NaCl) stress in vitro. ­ Acta Bot. Croatica, 76(2): 146­153. KIREMIT M.L., ARSLAN E., 2016 ­ Effects of salt stress on shallot growth. ­ European J. Hort. Sci., 81: 267­275. KOUR D., KHAN S.S., KAUR T., KOUR H., SINGH G., YADAV A., YADAV A.N., 2022 ­ Drought adaptive microbes as bioinoculants for the horticultural crops. ­ Heliyon, 8(5): e09493. KUBALA S., WOJTYLA Ł., QUINET M., LECHOWSKA K., LUTTS S., GARNCZARSKA M., 2015 ­ Enhanced expression of the proline synthesis gene P5CSA in relation to seed osmopriming improvement of Brassica Adv. Hort. Sci., 2025 39(2): 149­162 162 napus germination under salinity stress. ­ J. Plant Physiol., 183: 1­12. KUL R., ARJUMEND T., EKINCI M., YILDIRIM E., TURAN M., ARGIN S., 2021 ­ Biochar as an organic soil conditioner for mitigating salinity stress in tomato. ­ Soil Sci. Plant Nutr., 67(6): 693­706. MANSOUR M.M.F., ALI E.F., 2017 ­ Evaluation of proline functions in saline conditions. ­ Phytochem., 140: 52­ 68. MARDHIANA F., SOEPARJONO S., DAN HANDOYO T., 2018) ­ Pengaruh konsentrasi dan waktu aplikasi NaCl terhadap hasil dan mutu cabai merah (Capsicum Annum L.). ­ J. Appl. Agr. Sci., 2(1): 1­8. MUNNS R., TESTER M., 2008 ­ Mechanisms of salinity tolerance. ­ Ann. Rev. Plant Biol., 59: 651­681. ORZECHOWSKA A., TRTÍLEK M., TOKARZ K.M., SZYMAŃSKA R., NIEWIADOMSKA E., ROZPĄDEK P., WĄTOR K., 2021 ­ Thermal analysis of stomatal response under salinity and high light. ­ Inter. J. Mol. Sci., 22(9): 4663. PRANASARI R., NURHIDAYATI T., PURWANI K., 2012 ­ Persaingan Tanaman Jagung (Zea mays) dan Rumput Teki (Cyperus rotundus) pada Pengaruh Cekaman Garam (NaCl). ­ J. Sains Seni ITS, 1 (1). RATNARAJAH V., GNANACHELVAM N., 2021 ­ Effect of abiotic stress on onion yield: A review. ­ Adv. Technol., 1(1): 147­160. RUIZ­LOZANO J.M., PORCEL R., AZCON C., AROCA R., 2012 ­ Regulation by arbuscular mycorrhizae of the integrated physiological response to salinity in plants: New challenges in physiological and molecular studies. ­ J. Exp. Bot., 63(11): 4033­4044. RUSTIKAWATI R., HERISON C., SUTRAWATI M., UMROH D., 2023 ­ Assessment of salinity tolerance on chili pepper genotypes. ­ EDP Sciences, E3S Web Conferences, 373: 03023. SAPARSO, FAOZI K., PUTRA F.P., 2024 ­ Assessing the air salinity on agro‐physiological response of Brassica oleracea var. capitata and Brassica oleracea var. botrytis. ­ J. Appl. Nat. Sci., 16(1): 77­85. SAPARSO, SUDARMAJI A., MUSTHAFA M.B., 2023 ­ Physiological aspects of the growth of Corns (Bonanza 9‐F1 and Bisi‐18) to air salinity conditions on coastal area. ­ 3rd Inter. Conf. Sustainable Agriculture for Rural Development, ICSARD 2022, Atlantis Press, Dordrecht, The Netherlands, pp. 362­372. SHOKAT S., GROßKINSKY D.K., 2019 ­ Tackling salinity in sustainable agriculture‐what developing countries may learn from approaches of the developed world. ­ Sustainability, 11(17): 1­19. SIDABARIBA C.J., SUDJATMIKO S., 2023 ­ Pengaruh perlakuan pupuk organik terhadap pertumbuhan dan hasil tiga varietas bawang merah (Allium cepa var. aggregatum). ­ Prosiding Seminar Nasional Pertanian Pesisir, 2(1): 150­164. SILVA­ORTEGA C.O., OCHOA­ALFARO A.E., REYES­AGÜERO J.A., AGUADO­SANTACRUZ G.A., JIMÉNEZ­BREMONT J.F., 2008 ­ Salt stress increases the expression of p5cs gene and induces proline accumulation in cactus pear. ­ Plant Physiol. Biochem., 46(1): 82­92. SOLTABAYEVA A., ONGALTAY A., OMONDI J.O., SRIVASTAVA S., 2021 ­ Morphological, physiological and molecular markers for salt‐stressed plants. ­ Plants, 10(2): 243. SUHARJO U.K.J., MARLIN M., PURNAMA D.S., 2021 ­ Use of organic materials to reduce salinity stress in shallot plants. ­ National Seminar in the Framework of the 45th Anniversary of UNS, 5(1): 430­437. SUSANAWATI S., FAUZAN M., 2019 ­ Risk of shallot supply chain: an analytical hierarchy process (AHP) model in Brebes Java, Indonesia. ­ Int. J. Supply Chain Manag., 8(1): 124 ­131. SYAMSIYAH J., HERAWATI A., BINAFSIHI W., 2020 ­ Study of levels water salinity on the growth of varieties of shallots (Allium ascalonicum L.) in Alfisols. ­ IOP Conference Series: Earth and Environmental Science. IOP Publishing, 423(1): 012065. SYAMSUDDIN N., SANTOSO N., DIATIN I., 2019 ­ Inventarisasi Ekosistem Mangrove di Pesisir Randutatah, Kecamatan Paiton, Jawa Timur. ­ J. Pengelolaan Sumberdaya Alam dan Lingkungan, 9(4): 893­903. TAVAKKOLI E., RENGASAMY P., MCDONALD G.K., 2010 ­ High concentrations of Na+ and Cl– ions in soil solution have simultaneous detrimental effects on growth of faba bean under salinity stress. ­ J. Exp. Bot., 61(15): 4449­4459. TÜRKAN I., DEMIRAL T., 2009 ­ Recent developments in understanding salinity tolerance. ­ Environ. Exp. Bot., 67(1): 2­9. WANI A.S., IRFAN M., HAYAT S., AHMAD A., 2012 ­ Response of two mustard (Brassica juncea L.) cultivars differing in photosynthetic capacity subjected to proline. ­ Protoplasma, 49: 75­87. ZAINUDDIN M., HAMID N., MUDIARTI L., KURSISTYANTO N., ARYONO B., 2017 ­ Pengaruh Media Hiposalin dan Hipersalin terhadap Respon Pertumbuhan dan Biopigmen Dunaliella salina. ‐ Jurnal Enggano, 2(1): 46­ 57. ZHANG P., SENGE M., DAI Y., 2016 ­ Effects of salinity stress on growth, yield, fruit quality, and water use efficiency of tomato under hydroponics system. ­ Rev. Agric. Sci., 4: 46­55.