Acta agriculturae Slovenica, 118/2, 1–17, Ljubljana 2022 doi:10.14720/aas.2022.118.2.2417 Original research article / izvirni znanstveni članek Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress Mostafa AHMADIZADEH 1, 2, Ashkan ASGARI 1, 3, Hossein PASALARI 1 Received November 10, 2021; accepted March 22, 2022. Delo je prispelo 10. novembra 2021, sprejeto 22. marca 2022 1 Areas, Minab Higher Education Center, University of Hormozgan, Bandar Abbas, Iran; Research Group of Agroecology in Dryland 2 Corresponding author, e-mail: ahmadizadeh.mostafa@gmail.com 3 Corresponding author, e-mail: asgariashkan6@gmail.com Comprehensive seed priming assessment of Hibiscus sab- dariffa L. in germination and seedling growth stage under salt stress Abstract: This study was performed to appraise the ef- fects of several seed pretreatment solutions and priming time on seed germination indices and growth characteristics of Hi- biscus sabdariffa L. in various salt stress levels. Seed priming was accomplished by KCl (1 and 2 %), Na2SO3 (0.5 and 1 %), KNO3 (0.5 and 1 %), and Ca2CO3 (1 and 2 %) as halopriming and distilled water as hydropriming at 12 and 24 h priming durations and control (non-primed), then primed seeds ex- posed to four levels (0, 50, 100, 200 mM) of NaCl solutions. The highest germination percentage was observed in 12 and 24 h hydropriming (63.3 and 53.3 %) and non-primed (56.6 %) under normal condition, respectively. Besides, there was no germinated seed at 24 h priming by 0.5 and 1 percent- age of KNO3. Under saline condition, 24 h 2 % Ca2CO3 had the highest germination percentage (43.3 %) in 50 mM, while 12 h treatment with 0.5 % Na2SO3 (33.3 %) had high germina- tion percentage in 100 mM levels of saline conditions. Also, the highest germination rate index was observed in 0.5 % Na2SO3 with 12 h treatment time (4.05 and 3.95 respectively) in 50 and 100 mM levels of saline conditions. Overall, salt stress considerably reduced germination and growth traits of Hibiscus sabdariffa L. seedlings. Considering the effect of vari- ous seeds priming of Hibiscus sabdariffa L. on germination indices like germination percentage and mean germination time, the importance of priming duration and type of prim- ing solutions could be concluded. Key words: abiotic stress; medicinal plant; roselle; seed treatment Ocena predobravnavanja semen vrste osleza Hibiscus sab- dariffa L. v razvojnih stopnjah kalitve in kalice v razmerah solnega stresa Izvleček: V raziskavi so bili ocenjeni učinki predobrav- navanja semen z različnimi raztopinami in časi obravnavanja na kalitveni indeks in rastne lastnosti vrste Hibiscus sabdarif- fa L. v razmerah različnega solnega stresa. Predobravnavanje semen je bilo izvedeno z raztopinami KCl (1 in 2 %), Na2SO3 (0,5 in 1 %), KNO3 (0,5 in 1 %), in Ca2CO3 (1 in 2 %) kot obravnavanje s solmi in z destilirano vodo kot vodno obrav- navanje za 12 in 24 h ter kontrolo (brez predobravnavanja). Po tem so bila ta semena izpostavljena raztopinam štirih koncentracij natrijevega klorida (0, 50, 100, 200 mM NaCl). Največji odstotek kalitve je bil ugotovljen pri semenih, ki so bila predobravnavana z vodo za 12 in 24 ur (63,3 in 53,3 %) in pri netretiranih semenih (56,6 %) v normalnih razmerah. Pri predobravanavanju semen za 24 ur z 0,5 in 1 % raztopino KNO3 ni vzklilo nobeno seme. V razmerah slanosti je imelo 24 urno obravnavanje z 2 % raztopino Ca2CO3 največji odsto- tek kalitve (43,3 %) pri 50 mM med tem, ko je imelo12 urno obravnavanje z 0,5 % raztopino Na2SO3 (33,3 %) še vedno velik odstotek kalitve v razmerah 100 mM slanosti. Največja vrednost indeksa kalitve je bila ugotovljena pri obravnavanju z 0,5 % raztopino Na2SO3, z 12 urnim časom obravnavanja (4,05 in 3,95) v razmerah 50 in 100 mM slanosti. Nasplošno je solni stres znatno zmanjšal kalitev in rastne parameter se- jank osleza Hibiscus sabdariffa L.. Upoštevaje učinke različnih predobravnavanj semen osleza Hibiscus sabdariffa L. na kali- tvena indeksa kot sta odstotek kalitve in poprečni čas kalitve je potrebno pri tem posebej upoštevati pomen časa obravna- vanja in vrsto raztopine za obravnavanje. Ključne besede: abiotski stres; zdravilna rastlina; Hibi- scus sabdariffa L.; obravnava semen Acta agriculturae Slovenica, 118/2 – 20222 M. AHMADIZADEH et al. 1 INTRODUCTION Roselle (Hibiscus sabdariffa L.) is a member of the Malvaceae family (Shruthi et al., 2018), which origi- nally belonged to Malaysia and India (Mahadevan et al., 2009), and cultivated in tropical and subtropical climates (Da-Costa-Rocha et al., 2014). It is perennial or annual sub-shrub or woody-based herb, and widely grown in subtropical and tropical zones (Ibrahim et al., 2013). These plant species have played a key role in people’s living because they provide humanity’s needs that are food, clothes, shelter, and medicines (Riaz & Chopra, 2018)polysaccharides and organic acids thus having enormous prospective in modern therapeutic uses. The study aimed to review and document all the available evidence and information about the calyces of Hibiscus sabdariffa (roselle. Roselle is used in tradition- al medicine, due to overfill in phytochemicals like poly- phenols, particularly anthocyanins, polysaccharides, and organic acids; hence, it has significant potential in modern medicinal applications (Riaz & Chopra, 2018; Sukkhaeng et al., 2018). It is traditionally cultivated ow- ing to the usage of calyces, stems, leaves, and seeds as all organs have pharmacological and other uses (Wright et al., 2007). Calyx products are applied in indigenous medicine to treat high blood pressure, liver diseases and fever (Ali et al., 2005). Roselle extracts are increasingly developed for medications, food, and cosmetics (Farns- worth & Bunyapraphatsara, 1992). The presence of salt in the water or soil is consid- erable challenge for plant production in the world. It is most prevalent in dryland and coastal areas. Due to un- suitable irrigation and drainage management, limited rain, high evaporation, and saline irrigation water, salt concentration in the soil and water is increasing inland (Ibrahim, 2016). This problem takes about 3.7 million acres of the area of food production every year (Munns & Tester, 2008). Therefore, half of the cultivation area will be lost by the Mid-21st century (Wang et al., 2003). Salt stress became a limitation factor to the production of the crops, and the majority of crops are extremely sensitive to saline soil and water (Lin et al., 2017; Ah- madizadeh et al., 2016). Seed germination and seedling growth are the susceptible stages to abiotic stress, and abiotic stress can be slowed or stopped the germination of seeds (Ahmadizadeh et al., 2011; Galal, 2017). Rouhi et al. (2011), Ahmadizadeh et al. (2011), Ansari et al. (2013), and Ebrahimi et al. (2014) stated that raising the stress had a negative impact on the germination rate. In the past decade, several strategies have been ap- plied to improve abiotic stress tolerance in crops. There are various methods to enhance crop growth and devel- opment in salt-affected conditions (Hussain et al., 2016; Feghhenabi et al., 2020). One of the appropriate meth- ods is pretreatment, like prime the seeds with various materials before sowing (Ali et al., 2017; Subramanyam et al., 2019). Seed pretreatment as a practical, cost-effec- tive, and low-risk enhancing germination of seed and seedling growth through pre-germinating metabolic processes improvement (Jime’nez-Arias et al., 2015; Mi- gahid et al., 2019). Priming of seed is moderate stress, which activates a stress-reaction mechanism (Bhanu- prakash & Yogeesha, 2016). Priming of seed is a physi- ological method of seed hydration and drying to ame- liorate the pre-germinate metabolism under stressed conditions. The primed seeds exhibit quicker and nor- mal seed germination (Hasanuzzaman & Fotopoulos, 2019), and seed priming adjusts the biochemical and physiological of the embryo. Priming also decreases the seeds sensitivity to unfavorable conditions (Afzal et al., 2016). Several researchers have indicated that seed prim- ing enhances the well establishment and growth of plants (Farooq et al., 2010; Kerchev et al., 2020; Fegh- henabi et al., 2020). The beneficial impacts of seed priming in saline conditions have been shown in sev- eral crops for instance, pepper (Khan et al., 2009), okra (Dkhil et al., 2014), tomato (Ebrahimi et al., 2014), ro- sella (Galal, 2017), and Silybum marianum (L.) Gaertn. (Migahid et al., 2019). Latef et al. (2020) studied the im- pact of priming with Al2O3 nanoparticles on the growth of roselle, and the results showed that Al2O3 nanoparti- cles influenced growth traits, like dry mass, fresh mass, root, and shoot length. Shruthi et al. (2018) concluded pretreatment with GA3, KNO3, and hot water to study the influence of seed priming on germination of Ro- selle (Hibiscus sabdariffa L.), they indicated the posi- tive impact of seed pretreatment on the properties of germination speed and germination percentage. Nas- sar (2010) reported the positive results of seed priming and organic fertilizer on the yield and quality of ro- selle. Sheyhakinia et al. (2020) showed ameliorate of salt stress tolerance by jasmonic acid in roselle. Their results showed that jasmonic acid protected roselle seedlings against salinity damage. Germination indices and seed- ling traits of two tomato cultivars are influenced by the great potential value of seed treatment with CaCl2 and KNO3 solution under salinity conditions. In contrast, enhanced salinity concentrations led to a significant reduction in germination indices and seedlings growth (Ebrahimi et al., 2014). Soil salinity is one of the principal widespread abiotic stresses, which has adverse effects on crop pro- duction (Ismail et al., 2007; Ahmadizadeh et al., 2021). Appropriate seed germination is a prerequisite for the successful stand establishment of plants in unfavorable Acta agriculturae Slovenica, 118/2 – 2022 3 Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress environments such as low moisture, saline water, and soil, which are limiting germination factors (Ahmadi- zadeh, 2013). The fast and uniform germination and seedling establishment are influential factors for plant performance. There are several priming techniques, which are helpful for successful stand establishment of plants in abiotic stress conditions. Therefore, the study aimed to investigate the effects of various priming in- cluding KCl, Na2SO3, KNO3, and Ca2CO3 and hydro- priming of seeds on germination at different priming durations under normal and various levels of salinity conditions. 2 MATERIAL AND METHODS In order to assess the effects of various seed prim- ing compounds and priming durations on seed germi- nation indices and growth characteristics of Hibiscus sabdariffa L. seedlings in various levels of salt stress conditions were studied at the agricultural laboratory of Minab higher education center, university of Hor- mozgan. An experiment was conducted in a factorial experiment based on a completely randomized design with three replications. Priming treatments consisted of halopriming with KNO3 (0.5 and 1 %), Na2SO3 (0.5 and 1 %), KCl (1 and 2 %) and Ca2CO3 (1 and 2 %), and hydropriming with distilled water and control (non- primed), priming durations was 12 and 24 h, then seeds exposed to four levels (0, 50, 100, 200 mM) of NaCl so- lution. For any treatments, disinfected seeds were im- mersed in 50 ml of the prepared solution for 12 and 24 h in covered glass containers to preserve evaporation loss. The seeds were then rinsed with distilled water several times, afterward dried back at room tempera- ture (25 °C) for 24 h to be dried (Ebrahimi et al., 2014; Ibrahim, 2016; Aghdaei et al., 2019). Fifteen healthy primed seeds of roselle were placed in petri dishes on two layers of filter paper, then 8 ml of the salinity solutions (0, 50, 100, and 200 mM NaCl). To germinate the seeds, the petri dishes were put in an incubator at 26 ± 1◦C. Germination of Hibiscus sab- dariffa L. the seeds were counted as a germinated seed once they displayed extension of radicle almost 2 mm. The germination count was recorded every 24 h up to 7 days. At the end of the first week, and germination percentage (GP), germination rate index (GRI), mean germination time (MGT), germination index (GI), and vigor index (VI) were calculated based on the following equations (Al-Mudaris, 1998): GP = (N/M) * 100 (1) where GP is germination percentage, N is the total number of germinated seeds at the end of seven days, and M is the total number of cultivated seeds. GRI = (G1/1) + (G2/2) + …+ (Gx/x) (2) G1 = germination percent in first day. G2 = germination percent in second day to final experiment, MGT = (fx) / f (3) where f is the number of newly germinated seeds on each day and x is the day of counting, GI = (7 * N1) + (6 * N2) + (5 * N3) + … (4) N1, N2, . . . = the number of germinated seeds in first day, second day and . . ., VI = GP × Seedling length (SL) (El- ouaer & Hannachi, 2012), (5) Also, fresh shoot mass, fresh root mass, shoot length, root length, dry shoot mass and dry root mass were measured. Mass of root and shoot were measured from the sample mass before and after drying at 70 °C for 12 h. the data were analyzed using SAS software, and means comparisons were done by the least significant difference test (LSD) at p < 0.05 level of confidence. The Excel software was used to draw figures. 3 RESULT AND DISCUSSION Seed germination and early establishment of seed- ling are the crucial stages for the crops, and these two stages are the delicate growth stages in unfavorable en- vironments (Begcy et al., 2018). Seed germination is sometimes prevented or delayed under different abiotic stresses (Fazlali et al., 2013; Muhie et al., 2020a,b). Ro- selle is sensitive to germination and early seedling de- velopment in saline conditions (Bahaeldeen et al., 2012; Al-Tohafi et al., 2015; Kadamanda, 2019). Considering to the value and privilege of the Hibiscus sabdariffa products, particularly medicinal value, this study was conducted to evaluate the influence of various priming approaches in different NaCl concentrations on germi- nation indices and seedling traits of roselle plants in petri dish at a controlled experimental environment. The analysis of variance showed a highly significant (p < 0.01) difference between various priming treatments in terms of germination indices and seedling growth traits (Table 1). Also, the result revealed a significant difference among the salinity levels. The priming × sa- linity interaction effect was significant for all studied traits (Table 1). High concentrations of salinity pre- vent and reduce the performance of most plants, but seed emergence is the utmost momentous process for well seed germination in medicinal plants (Nadjafi et al., 2006; Reed et al., 2022). The highest germination Acta agriculturae Slovenica, 118/2 – 20224 M. AHMADIZADEH et al. rate and percentage of T. polium seeds were obtained at concentrations of 500-2500 ppm GA3. Washing and chilling (5°C. The highest germination percentage (GP) (36.93 %) was observed in normal condition, while un- der the salinity conditions the highest GP (23.24 %) was observed under 50 mM salinity condition (Table 2). The decreasing in the percentage of germination may be associated with the increase of external osmotic pressure that has an impact on the water absorption of the seed, as well as, owing to the accumulation of some ions in the embryo, which may result in stimulation of the metabolic processes of germination and ultimate- ly leading to cells death in the embryo (Maher et al., 2013; Feghhenabi et al., 2020). Afkari Bajehbaj (2010) and Shereiwy et al. (2021) demonstrated that enhanc- ing salinity levels decreased final germination in seeds, but, the adverse impact of salinity on primed seeds was less than unprimed seeds. The highest germination rate index (GRI) (5.06) was observed in normal condition, while under the salinity conditions the highest GRI was observed under 50 mM salinity condition that had sig- nificantly different from normal condition (Table 2). The highest GI was observed in normal condition, under the low level of salinity conditions the GI reduc- tion was 46 percentage, and the highest GI in stress condition was observed under 50 mM salinity condi- tion (Table 2). The highest VI was observed in nor- mal condition, and there was significantly difference between the various levels of salinity stress (Table 2). The means comparison under different levels of salin- ity stress revealed the highest MGT under 50, and 100 mM salinity conditions (Table 2). In this respect, Kaveh et al. (2011), Thiam et al. (2013), and Ibrahim (2016) indicated that enhancing the concentration of salinity improved germination time and reduced the germina- tion percentage. In general, low levels of salinity cause a dormancy and low impact on the germination rate, but ascending concentration of salt prevents the seed germination and reduces the percentage of germina- tion (Khan & Weber, 2006; Shannon & Grieve, 1998). There was a significant difference between control and salinity conditions in terms of shoot and root mass. The highest of shoot fresh mass (0.19 g), root fresh mass (0.023 g) and root dry mass (0.002 g) were observed at non-salinity condition (control) but the highest shoot dry mass (0.019) was achieved at salinity condition (Ta- ble 2), suggesting that root growth is more sensitive to salinity than shoot growth. Amiri et al. (2010) with the study of germination characteristics of Cynara scolymus L. and Echinacea purpurea (L.) Moench under salinity stress demonstrated that shoot dry mass was reduced by enhancing salt concentration in studied medicinal plants. The similar finding was reported by research- M ea n Sq ua re S. O .V D F G P G RI M G T G I V I Sh L RL FS hM FR M D Sh M D RM Sh /R Pr im 18 86 1. 39 ** 15 .2 5* * 4. 78 ** 90 7. 27 ** 49 42 5. 72 ** 14 .9 3* * 5. 62 ** 0. 02 ** 0. 00 04 4* * 0. 00 03 3* * 0. 00 00 03 5* * 20 2. 13 ** Sa lin ity 3 12 15 6. 73 ** 23 5. 69 ** 33 .8 2* * 88 4. 45 ** 10 01 02 3* * 21 3. 34 ** 57 .5 6* * 0. 34 ** 0. 00 48 ** 0. 00 34 ** 0. 00 00 37 2* * 13 94 .1 1* * P* S 54 19 7. 69 ** 4. 51 ** 1. 19 ** 13 32 3. 17 ** 21 36 7. 41 ** 2. 73 ** 1. 33 ** 0. 00 4* * 0. 00 01 4* * 0. 00 00 68 ** 0. 00 00 00 77 ** 88 .4 4* * Er ro r 15 2 35 .4 1 0. 98 0. 69 43 .1 4 31 52 .8 6 0. 50 0. 18 0. 00 1 0. 00 00 1 0. 00 00 08 9 0. 00 00 00 13 25 .1 2 Ta bl e 1: A na ly si s o f v ar ia nc e fo r sa lin ity a nd p ri m in g eff ec ts o n so m e ge rm in at io n ch ar ac te ri st ic s o f H ib is cu s s ab da ri ffa ** : i s s ig ni fic an t a t 1 % , G P: G er m in at io n Pe rc en ta ge , G RI : G er m in at io n Ra te In de x, M G T: M ea n G er m in at io n Ti m e, G I: G er m in at io n In de x, V I: V ig or In de x, S hL : S ho ot le ng th , R L: R oo t L en gt h, F Sh M : F re sh S ho ot M as s, FR M : Fr es h R oo t M as s, D Sh M : D ry S ho ot M as s, D RM : D ry R oo t M as s, Sh /R : S ho ot /R oo t r at io Acta agriculturae Slovenica, 118/2 – 2022 5 Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress Sa lin ity m M G P (% ) G RI M G T (d ay ) G I V I Sh L (c m ) RL (c m ) FS hM (g ) FR M (g ) D Sh M (g ) D RM (g ) Sh /R 0 36 .9 3 a 5. 06 7 a 1. 66 6 b 38 .6 3 a 31 4. 5 a 4. 85 9 a 2. 62 8 a 0. 19 00 a 0. 02 36 a 0. 01 67 b 0. 00 20 2a 8. 35 0 c 50 23 .2 4 b 2. 29 7 b 2. 36 7 a 20 .8 4 b 13 6. 7 b 3. 36 3 b 1. 60 1 b 0. 16 73 b 0. 01 61 b 0. 01 81 a 0. 00 15 7b 11 .7 11 b 10 0 19 .3 8 c 1. 86 9 c 2. 27 4 a 17 .4 9 c 80 .3 c 2. 39 4 c 1. 21 7 c 0. 12 73 c 0. 01 14 c 0. 01 90 a 0. 00 13 7c 14 .6 11 a 20 0 1. 49 d 0. 16 1 d 0. 69 3 c 1. 35 d 2. 84 d 0. 24 3 d 0. 19 6 d 0. 01 56 d 0. 00 15 d 0. 00 26 c 0. 00 01 3d 3. 09 2 d LS D 2. 20 24 0. 36 65 0. 30 92 2. 43 09 20 .7 8 0. 26 42 0. 16 1 0. 01 22 0. 00 12 0. 00 11 0. 00 01 1. 85 49 Ta bl e 2: M ea n co m pa ri so n of s al in ity le ve ls o n ge rm in at io n in di ce s a nd s ee dl in g gr ow th tr ai ts in H ib is cu s s ab da ri ffa G P: G er m in at io n Pe rc en ta ge , G RI : G er m in at io n R at e In de x, M G T: M ea n G er m in at io n Ti m e, G I: G er m in at io n In de x, V I: V ig or In de x, S hL : S ho ot le ng th , R L: R oo t L en gt h, F Sh M W : F re sh S ho ot M as s, FR M : F re sh R oo t M as s, D Sh M : D ry S ho ot M as s, D RM : D ry R oo t M as s, Sh /R : S ho ot /R oo t r at io ers in other species consisting of roselle (Galal, 2017), safflower (Kaya et al., 2003; Khodadad, 2011), triticale (Atak et al., 2006), and tomato (Ebrahimi et al., 2014). There are multiple pretreatment approaches ap- plied and classification based on the priming com- pounds. These comprise halo-priming, hydro-priming, hormone priming, osmo-priming, solid matrix, hard- ening, stratification, and thermal shock and humidifi- cation. The hydropriming, osmo-priming, haloprim- ing, and hormone priming techniques commonly had been used for seed treatment (Ashraf & Foolad, 2005; Eskandari, 2013; Paparella et al., 2015). Water potential, temperature, seed vigor, priming duration, seed primed storage condition, and plant species are the factors that influence the response of the seed to priming. There- fore, the optimization and fine-tuning of the priming approach is substantial to obtain the best outcome (Ra- tikanta & Kalipada, 2013). Hydropriming affect some of the required meta- bolic processes for germination to happen without ger- mination be accomplished, faster imbibition, further, softening of seed coat led to lesser mechanical preven- tion as a result of priming (Askari-Nejad & Farahmand, 2012). Seed pretreatment by inorganic salts enhances the enzymes activity engaged in the germination of seed and changes the mobilization of organic substanc- es’ to various embryo parts (Aghdaei et al., 2019). Prim- ing for 12 h with 0.5 % Na2SO3, 12 and 24 h with 2 % Ca2CO3, 12 h with 1 % KCl, 12 h with 1 % Na2SO3 and various hydro-prim showed the highest GP (Table 3). The highest GRI was in 12 h priming with 0.5 % Na2SO3, 1 % Na2So3 and hydro-prim (Table 3). The GRI illus- trate the percentage of germination on every day of the germination period. Higher GRI values display prompt and high germination (Fuller et al., 2012). Priming with 0.5 % Na2SO3 and 1 % Ca2CO3 in 12 h revealed the lowest median germination time (MGT) (Table 3). The lower MGT showed the faster germination of a seeds population (Fuller et al., 2012). The highest GI was in 12 h priming with 0.5 % Na2SO3, hydro-prim, and 24 h with 2 % Ca2CO3 (Table 3). Priming with 12 h 0.5 % Na2SO3, hydro-prim, and 24 h with 2 % Ca2CO3 showed the highest VI (Table 3). In contrast, 12 and 24 h prim- ing with two percentage KCl had the lowest GRI, GI, VI, and GP (Table 3). The highest shoot length was in 24 h priming with 2 % Ca2CO3 (4.19 cm), 1 % Ca2CO3 (3.91 cm), 1 % Na- 2SO3 (3.89 cm), and 12 h priming with 1 % KCl (3.74 cm), there were no statistically significant difference among these treatments. Priming with 24 h with 2 % Ca2CO3 showed the highest root length (Table 3). In terms of shoot mass at 24 h priming with 2 % Ca2CO3 (0.19 g), 1 % Ca2CO3 (0.18 g), and 1 % Na2So3 (0.17 Acta agriculturae Slovenica, 118/2 – 20226 M. AHMADIZADEH et al. es have been utilized for better germination of seeds in both normal and unfavorable environments (Jisha et al., 2012). The positive and affirmative effects of priming were observed in adverse condition than optimal con- ditions (Ashraf & Foolad, 2005; Chen & Arora, 2011; Ibrahim, 2016). Suggested priming mechanisms were consisting of the incidence of epigenetic alterations, also the transcription factors accumulation and inactive and inhibition of signaling proteins. These mechanisms are induced against the stress, hence improved resulting in a well and effective defense mechanism (Tanou et al., 2012). Some treatments and techniques were able to de- velop well establishment of crops in stressful conditions (Soeda et al., 2005; Patade et al., 2009). The highest GP was in 0, 12, 24 hours hydroprim- ing under normal condition. Also, 2 % Ca2CO3, 0.5 % Na2So3, and 1 % KCl in 12 hours treatment showed high GP under normal condition (Figure 1). enhancing the growth characteristics resulting from seed priming by water soaking could be owing to the impact of seed hydropriming on the fast and sound establishment of plants (Ashraf & Foolad, 2005). The lowest GP was ob- served in 0.5 % KNO3 in 24 hours pretreatment in all studied conditions, 0.5 % KNO3 in 12 hours pretreat- ment under 200 mM salinity condition, as well as, the same results were observed by 24 pretreatments of 1 % g) had the highest shoot mass that there were no sta- tistically significant difference among these treatments. Also, 24 h priming with 2 % Ca2CO3 root mass (Table 3). The highest dry shoot mass was in 24 h priming with 1 % Ca2CO3, and 2 % Ca2CO3, priming with 24 h 2 % Ca2CO3, hydro-prim, and 12 h with 2 % Ca2CO3 showed the highest dry root mass (Table 3). The positive effects of various priming approaches like priming the tomato seed by potassium nitrate on germination (Lara et al., 2014), hydropriming on sorghum and rice germina- tion percentage (Farooq et al., 2006; Moradi & Younesi, 2009), and salicylic acid on Solanum melongena L. seed germination percentage (Mahesh et al., 2017), as well as, enhance of the shoot and root length of cotton (Gos- sypium hirsutum L.) in hydropriming (Shaheen et al., 2015) have been reported. Plant cell turgor reduction and decrease of shoot and root length caused by salinity stress (Werner & Finkelstein, 1995). Also, it was suggested that salinity stress acts firstly on water uptake. Moreover, Na+ and Cl- accumulation prevent the metabolism of cells divid- ing and expanding (Neumann, 1997), less germination, and even resulting in seed or embryo death. In addi- tion, salt stress leads prevent and decrease the enzymes activities that may be significantly associated with seed germination (Katembe et al., 1998). Priming approach- Figure 1: Effect of various priming under four level of salt stress on germination percentage of Hibiscus sabdariffa L. 1: non-primed, 2: Hydro 12h , 3: Hydro 24 h, 4: KNO3_0.5 % 12 h , 5: KNO3_0.5 % 24 h , 6: KNO3_1 % 12 h, 7: KNO3_1 % 24 h, 8: Na2SO3_0.5 % 12 h, 9: Na2SO3_0.5 % 24 h , 10: Na2SO3_1 % 12 h, 11: Na2SO3_1 % 24 h, 12: KCl_1 % 12 h, 13: KCl_1 % 24 h, 14: KCl_2 % 12 h , 15: KCl_2 % 24 h, 16: Ca2CO3_1 % 12 h, 17: Ca2CO3_1 % 24 h, 18: Ca2CO3_2 % 12 h , 19: Ca2CO3_2 % 24 h Acta agriculturae Slovenica, 118/2 – 2022 7 Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress Na2SO3, and 2 % KCl under 200 mM salinity condition, and 1 % Ca2CO3 in 12 hours pretreatment under 200 mM salinity condition (Figure 1). In saline conditions, 2 % Ca2CO3, 0.1 % Na2SO3 under 50 mM salinity, and 0.1 % Na2SO3 in 100 mM salinity showed the high GP. However, there was significantly different with the con- trol condition (Figure 1). The result implied that the best treatments in terms of GP were 12 h Hydro, 12 h Na2SO3_0.5 %, 24 h Ca2CO3_1 %, 24 h Ca2CO3_2 % in control, 100 mM salinity, 200 mM salinity, and 50 mM salinity conditions, respectively (Figure 1). Hydropriming (12 and 24 h), 0.5 % Na2SO3, and 1 % Na2SO3 in 12 h had the highest GRI in the normal condition. In saline conditions, 12 h seed priming by 0.5 % Na2SO3 under 50 mM salt stress condition and 12 h priming with 1 % KCl in 200 mM salt stress condi- tion, while there were zero GRI in 24 h pretreatment of seeds with 0.5 % KNO3 and 1 % KNO3 under salinity conditions, as well as, 1 % Na2SO3, 1 % Ca2CO3 and 2 % KCl under 200 mM salinity condition (Figure 2). The highest MGT was in 1 % Ca2CO3 and 2 % KCl with 12 and 24 priming hours under 200 and 100 mM salinity conditions, respectively. Also, there were no significant differences in 24 h priming with 2 % Ca2CO3 under 50 mM salinity conditions, 0.5 % Na2SO3, hydro-prim and 1 % Na2SO3 under 100 mM salinity conditions, and 12 h priming with 1 % Na2SO3 and 1 % Ca2CO3 in 100 mM Figure 2: Effect of various priming under four level of salt stress on germination rate index of Hibiscus sabdariffa L. 1: non-primed, 2: Hydro 12h , 3: Hydro 24 h, 4: KNO3_0.5 % 12 h , 5: KNO3_0.5 % 24 h , 6: KNO3_1 % 12 h, 7: KNO3_1 % 24 h , 8: Na2SO3_0.5 % 12 h, 9: Na2SO3_0.5 % 24 h , 10: Na2SO3_1 % 12 h, 11: Na2SO3_1 % 24 h, 12: KCl_1 % 12 h, 13: KCl_1 % 24 h , 14: KCl_2 % 12 h , 15: KCl_2 % 24 h, 16: Ca2CO3_1 % 12 h, 17: Ca2CO3_1 % 24 h, 18: Ca2CO3_2 % 12 h , 19: Ca2CO3_2 % 24 h salinity condition (Table 4). Similar results were report- ed by (Farooq et al., 2006) and (Qadir et al., 2011), who reported reducing MGT using CaCl2 primed seeds. Hydropriming (12 and 24 h) had the highest GI in normal conditions, and there were no significant differ- ences with hydropriming (control), 0.5 % Na2So3, and 1 % Na2SO3 in 12 h in normal condition (Table 4). The seeds with twelve-hour priming of 1 % KCl in 100 mM salinity, 0.5 % Na2So3, and 0.1 % Na2SO3 under 50 mM salinity showed high GI, but there were significant dif- ferences with the control condition (Table 4). Enhanc- ing the germination rate in treatment seeds can be il- lustrated through the enhanced synthesis of protein, the less term of metabolism in the germination stage, the influence on cell membrane phospholipids (Ansa- ri et al., 2013), enhance of cell division rate (Taylor & Harman, 1990), and faster absorption of water, better development in these seeds, which all eventually lead to enhancing of seed germination duration. Shahverdi et al. (2017), with priming the stevia seeds, indicated a considerable correlation between the germination per- centage enhancement and seed germination improve- ment factors. It seems that the efficiency of pretreat- ment of seed is affiliated with the elements like type and concentration of priming compound, duration of seed treatment by compounds (duration of priming). The 12 h treatment with hydro-prim, 1 % Na2So3, Acta agriculturae Slovenica, 118/2 – 20228 M. AHMADIZADEH et al. Pr im % Ti m e G P (% ) G RI M G T (d ay )G I V I Sh L (c m ) RL (c m ) FS hM (g ) FR M (g ) D Sh M (g ) D RW (g ) Sh /R H yd ro - C on tr ol 27 .9 17 2. 73 19 1. 91 04 25 .7 5 14 3. 33 1. 94 17 1. 20 58 0. 13 33 3 0. 01 53 33 0. 01 63 75 0. 00 16 33 8. 83 3 12 28 .3 33 3. 69 03 1. 94 92 28 .1 67 20 0. 46 2. 68 33 1. 80 83 0. 13 58 3 0. 01 54 17 0. 01 63 67 0. 00 16 42 7. 60 8 24 24 .5 83 3. 25 69 1. 74 05 25 .0 83 15 5. 67 2. 39 17 1. 62 5 0. 13 75 0. 01 78 33 0. 01 17 17 0. 00 18 83 4. 77 2 K N O 3 0. 5 12 19 .5 8 2. 01 39 1. 82 5 18 .3 33 88 .2 9 2. 46 67 0. 77 5 0. 13 16 7 0. 01 33 33 0. 01 56 67 0. 00 14 58 8. 27 7 24 0 0 0 0 0 0 0 0 0 0 0 0 1 12 22 .0 8 2. 68 75 1. 76 81 22 .0 83 12 6. 83 2. 82 5 1. 07 5 0. 12 5 0. 01 49 92 0. 01 51 25 0. 00 13 33 12 .9 93 24 0 0 0 0 0 0 0 0 0 0 0 0 N a 2 SO 3 0. 5 12 29 .5 83 4. 21 11 1. 36 82 31 .5 83 18 4. 92 3. 30 83 0. 1 0. 13 5 0. 01 51 58 0. 01 82 92 0. 00 13 67 11 .8 86 24 23 .3 33 2. 63 19 2. 01 41 22 .4 17 16 0. 33 3. 50 83 1. 74 17 0. 14 25 0. 01 27 92 0. 01 69 33 0. 00 13 67 13 .1 81 1 12 25 .8 33 3. 55 14 2. 02 31 24 .7 5 15 8. 67 2. 92 5 1. 47 5 0. 12 16 7 0. 01 13 42 0. 01 51 67 0. 00 12 17 10 .3 6 24 16 .2 5 1. 67 64 2. 39 15 13 .9 17 15 5. 67 3. 89 17 1. 95 83 0. 17 41 7 0. 01 43 5 0. 01 35 75 0. 00 10 5 11 .2 25 K C l 1 12 26 .2 5 3. 16 25 1. 96 7 25 .9 17 19 5. 5 3. 74 17 1. 52 5 0. 14 16 7 0. 01 33 75 0. 01 48 75 0. 00 11 75 10 .4 14 24 20 .8 33 2. 12 08 2. 29 43 19 .6 67 13 9 2. 72 5 1. 42 5 0. 13 16 7 0. 01 15 5 0. 01 65 5 0. 00 13 25 11 .5 48 2 12 14 .1 67 1. 31 25 1. 94 94 12 .7 5 63 .8 8 2. 28 33 0. 90 83 0. 10 58 3 0. 00 70 83 0. 01 52 58 0. 00 08 98 13 .8 17 24 14 .1 67 1. 25 2. 04 31 12 .2 5 67 .1 7 2. 29 17 1. 10 83 0. 10 83 3 0. 00 84 08 0. 01 29 75 0. 00 07 33 14 .1 43 C a 2 C O 3 1 12 17 .5 2. 10 42 1. 62 96 17 .3 33 13 3. 24 3. 17 5 1. 55 75 0. 12 91 7 0. 01 68 33 0. 01 24 75 0. 00 14 92 7. 63 3 24 21 .2 5 2. 54 86 1. 97 56 21 .1 67 14 5. 25 3. 91 67 2. 19 17 0. 18 08 3 0. 01 78 33 0. 01 94 33 0. 00 17 33 12 .9 76 2 12 25 .4 17 2. 63 75 2. 01 92 23 .8 33 18 9. 04 3. 14 17 1. 87 5 0. 13 75 0. 01 94 17 0. 01 59 67 0. 00 18 6. 90 2 24 27 .5 2. 99 86 2. 21 99 26 .5 83 23 9. 38 4. 19 17 2. 94 17 0. 19 0. 02 52 5 0. 02 08 67 0. 00 20 75 12 .0 33 LS D 5% 4. 80 01 0. 79 87 0. 67 38 5. 29 8 45 .2 89 0. 57 58 0. 35 08 0. 02 65 0. 00 27 0. 00 24 0. 00 03 4. 04 27 Ta bl e 3: M ea n co m pa ri so n of v ar io us p ri m in g on g er m in at io n in di ce s a nd s ee dl in g gr ow th tr ai ts in H ib is cu s s ab da ri ffa L . G P: G er m in at io n Pe rc en ta ge , G RI : G er m in at io n R at e In de x, M G T: M ea n G er m in at io n Ti m e, G I: G er m in at io n In de x, V I:V ig or In de x, S hL : S ho ot le ng th , R L: R oo t L en gt h, F Sh M : F re sh S ho ot M as s, FR M : F re sh R oo t M as s, D Sh M : D ry S ho ot M as s, D RM : D ry R oo t M as s, Sh /R : S ho ot /R oo t r at io Acta agriculturae Slovenica, 118/2 – 2022 9 Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress and 1 % KCl had the highest VI in normal condition, and there were no significant differences with 0.5 % Na2SO3, 1 % Ca2CO3, 2 % Ca2CO3, and 1 % KNO3 in 12 h treatments under normal condition, and 0.5 % Na- 2SO3 (12 h priming) in 50 mM salinity condition, 1 % Na2SO3, and hydro-prim in 24 h treatment at normal condition (Figure 3). The 12 h treatment with 0.5 % Na- 2SO3 in 50 mM salinity condition, 1 % KCl, 1 % Ca2CO3, 1 % Na2SO3, and the 24 h treatment with 1 % Na2SO3 had the highest shoot length in normal condition. Also, there were no significant differences with 12 h treat- ment by 1 % KNO3 under 100 mM salinity, 1 % KNO3, Figure 3: Effect of various priming under four level of salt stress on vigor index of Hibiscus sabdariffa L. 1: non-primed, 2: Hydro 12h , 3: Hydro 24 h, 4: KNO3_0.5 % 12 h , 5: KNO3_0.5 % 24 h , 6: KNO3_1 % 12 h, 7: KNO3_1 % 24 h , 8: Na2SO3_0.5 % 12 h, 9: Na2SO3_0.5 % 24 h , 10: Na2SO3_1 % 12 h, 11: Na2SO3_1 % 24 h, 12: KCl_1 % 12 h, 13: KCl_1 % 24 h , 14: KCl_2 % 12 h , 15: KCl_2 % 24 h, 16: Ca2CO3_1 % 12 h, 17: Ca2CO3_1 % 24 h, 18: Ca2CO3_2 % 12 h , 19: Ca2CO3_2 % 24 h Figure 4: Effect of various priming under four level of salt stress on shoot length of Hibiscus sabdariffa L. 1: non-primed, 2: Hydro 12h , 3: Hydro 24 h, 4: KNO3_0.5 % 12 h , 5: KNO3_0.5 % 24 h , 6: KNO3_1 % 12 h, 7: KNO3_1 % 24 h , 8: Na2SO3_0.5 % 12 h, 9: Na2SO3_0.5 % 24 h , 10: Na2SO3_1 % 12 h, 11: Na2SO3_1 % 24 h, 12: KCl_1 % 12 h, 13: KCl_1 % 24 h , 14: KCl_2 % 12 h , 15: KCl_2 % 24 h, 16: Ca2CO3_1 % 12 h, 17: Ca2CO3_1 % 24 h, 18: Ca2CO3_2 % 12 h , 19: Ca2CO3_2 % 24 h Acta agriculturae Slovenica, 118/2 – 202210 M. AHMADIZADEH et al. 2 % Ca2CO3 in normal condition, 24 h treatment by 1 % KCl, and 0.5 % Na2SO3 in normal condition (Figure 4). The highest root length was in hydro-prim, 1 % Ca2CO3 at 12 h in normal condition, and 0.5 % Na2SO3 at 12 h in 50 mM salinity condition, and there were no significant differences with 2 % Ca2CO3 at 12 h, 1 % Na2SO3, and hydroprim at 12 h in normal condition (Figure 5). Neumann (1995) also reported that salinity could quickly prevent root growth and thus the ability to uptake water and essential mineral nutrition. The 12 h treatment with 1 % Na2SO3, in 50 mM salinity condi- tion, 1 % Ca2CO3 and 1 % KCl had the highest shoot mass in normal condition. Also, there were no signifi- cant differences with 1 % Na2SO3 at 24 h, 2 % Ca2CO3 in 12 h treatment in normal condition and 1 % KNO3 in 12 treatment under 100 mM salinity (Table 4). The 24 h treatment with 1 % Na2SO3, 1 % KCl, and the 12 h treatment with 2 % Ca2CO3 had the high- est root mass in normal condition. Also, there were no significant different with 12 treatment of 1 % Na2SO3, 0.5% Na2SO3 in normal condition and 1 % Ca2CO3 un- der 50 mM salinity (Table 4). The results showed several priming had high dry shoot mass under various salin- ity conditions, for instance 2 % Ca2CO3, 1 % Ca2CO3, 1 % Na2SO3, 0.5 % Na2SO3, 0.5 % KNO3, and 1 % KCl illustrated the highest dry shoot mass under 100 mM salinity condition. Besides, 0.5 % Na2SO3, 1 % Ca2CO3, 0.5 % KNO3, 2 % Ca2CO3, 1 % KCl, 1 % KNO3 and 2 % KCl had the highest dry shoot mass under 50 mM salin- ity condition (Table 4). Seed priming by CaCl2, KCl, and NaCl were figured out to be effective in diminishing the negative impact of salinity on wheat via their effects on changing the levels of various plant phytohormones (Iqbal et al., 2006). The highest dry root length was in hydro-prim, 1 % Na2SO3, and 1 % KCl at 24 h, and 1 % Ca2CO3 at 12 h in normal condition, also, there were no significant differences with hydro-prim (12 h), 2 % Ca2CO3 (12 h), 0.5 % Na2SO3 (12 and 24 h), and 1 % KCl (24 h) in 50 mM salinity condition, 0.5 % Na2SO3 (24 h), 1 % Na2SO3 (24 h), and 1 % KNO3 (12 h) in 100 mM salinity condi- tion (Table 4). Abdollahi & Jafari (2012) demonstrated that KNO3 3 % treatment enhanced root length to primary shoot ratio more than NaCl 1 % under saline condition. This enhances the water uptake by the plant that may help the growth development of seedlings in saline conditions. In addition, application of the four potassium nitrate concentrations (0, 0.5, 1, and 2 %) on time to 50 percentage germination, and germination percentage of amaranth seeds revealed that using 0.5 percent of potassium nitrate decreased time to 50 % seed germination (Musa & Lawal, 2015). The 24 h treatment with 1 % KCl, 1 % Ca2CO3, and 2 % Ca2CO3 had the highest shoot and root ratio in 100 mM salinity condition. Also, there were no significant differences with 12 treatments of 1 % Ca2CO3, 2 % KCl, Figure 5: Effect of various priming under four level of salt stress on root length of Hibiscus sabdariffa L. 1: non-primed, 2: Hydro 12h , 3: Hydro 24 h, 4: KNO3_0.5 % 12 h , 5: KNO3_0.5 % 24 h , 6: KNO3_1 % 12 h, 7: KNO3_1 % 24 h , 8: Na2SO3_0.5 % 12 h, 9: Na2SO3_0.5 % 24 h , 10: Na2SO3_1 % 12 h, 11: Na2SO3_1 % 24 h, 12: KCl_1 % 12 h, 13: KCl_1 % 24 h , 14: KCl_2 % 12 h , 15: KCl_2 % 24 h, 16: Ca2CO3_1 % 12 h, 17: Ca2CO3_1 % 24 h, 18: Ca2CO3_2 % 12 h , 19: Ca2CO3_2 % 24 h. Acta agriculturae Slovenica, 118/2 – 2022 11 Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress Prim (%) Time salt MGT (day) GI FShM (g) FRM (g) DShM (g) DRM (g) Sh/R Hydro Control 0 2.05 56.33 0.19 0.020 0.0192 0.0025 7.79 50 2.85 18 0.19 0.021 0.0209 0.0017 16.36 100 2.73 28.66 0.14 0.02 0.0253 0.0023 11.17 200 0 0 0 0 0 0 0 12 h 0 1.58 68.66 0.15 0.025 0.0227 0.0023 10.07 50 2.30 23.33 0.21 0.023 0.0213 0.0020 10.52 100 2.9 19.33 0.17 0.013 0.0213 0.0022 9.82 200 1 1.33 0 0 0 0 0 24 h 0 1.49 59 0.19 0.03 0.0196 0.0033 5.90 50 2.19 28.66 0.21 0.021 0.0155 0.0023 6.71 100 2.94 10.66 0.14 0.016 0.0116 0.0018 6.46 200 0.33 2 0 0 0 0 0 KNO3_0.5 % 12 h 0 1.72 33.66 0.18 0.016 0.0201 0.00196 10.35 50 2.72 20.33 0.18 0.023 0.0221 0.0022 10.28 100 2.85 19.33 0.16 0.013 0.0203 0.0016 12.47 200 0 0 0 0 0 0 0 24 h 0 0 0 0 0 0 0 0 50 0 0 0 0 0 0 0 100 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 KNO3_1 % 12 h 0 2.02 40.33 0.21 0.043 0.0189 0.003 6.34 50 1.94 22 0.19 0.011 0.0216 0.0013 17.68 100 2.10 24.66 0.096 0.005 0.0198 0.0010 27.94 200 1 1.33 0 0 0 0 0 24 h 0 0.66 1.66 0.06 0.001 0.005 0.00053 3.12 50 0 0 0 0 0 0 0 100 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 Na2SO3_0.5 % 12 h 0 1.26 55.66 0.20 0.023 0.0189 0.00163 11.57 50 1.97 35 0.17 0.018 0.0239 0.00206 11.61 100 1.89 33.66 0.11 0.015 0.0228 0.00126 19.35 200 0.33 2 0.04 0.003 0.0075 0.0005 5 24 h 0 1.64 44.66 0.18 0.017 0.0202 0.0018 12.81 50 2.85 22.66 0.2 0.016 0.0211 0.00203 10.45 100 2.55 21 0.15 0.015 0.0236 0.00156 15.62 200 1 1.33 0.03 0.002 0.0027 0.0002 13.83 Continued on the next page Table 4: Mean comparison of priming and salinity interaction effect on germination indices and seedling growth traits in Hibiscus sabdariffa L. Acta agriculturae Slovenica, 118/2 – 202212 M. AHMADIZADEH et al. Na2SO3_1 % 12 h 0 1.36 45.33 0.14 0.016 0.0136 0.002 6.78 50 3.09 30 0.19 0.018 0.0217 0.00163 13.32 100 2.63 22.33 0.15 0.009 0.0252 0.00123 21.32 200 1 1.33 0 0 0 0 0 24 h 0 2.12 33.33 0.31 0.034 0.0188 0.0021 9.12 50 4.77 6.66 0.20 0.009 0.0116 0.00073 16.92 100 2.66 15.66 0.17 0.013 0.0238 0.0013 18.85 200 0 0 0 0 0 0 0 KCl_1 % 12 h 0 1.66 48 0.27 0.031 0.016 0.0018 8.91 50 2.70 28.66 0.14 0.010 0.0207 0.00173 12.33 100 1.83 26 0.15 0.011 0.0228 0.00117 20.40 200 1.66 1 0 0 0 0 0 24 h 0 1.89 42.66 0.21 0.025 0.0202 0.00243 8.64 50 2.66 23.66 0.19 0.015 0.0251 0.00203 12.32 100 2.61 12 0.12 0.005 0.0207 0.00083 25.22 200 2 0.333 0 0 0 0 0 KCl_2 % 12 h 0 2.21 25.66 0.15 0.007 0.0162 0.001267 13.56 50 2.58 15 0.18 0.009 0.0223 0.001467 15.48 100 3 10.33 0.09 0.0116 0.0224 0.00086 26.21 200 0 0 0 0 0 0 0 24 h 0 2.36 19.33 0.15 0.0103 0.0172 0.0012 15.12 50 3.22 9 0.12 0.0143 0.0173 0.00073 24.05 100 2.58 20.66 0.16 0.009 0.0174 0.001 17.4 200 0 0 0 0 0 0 0 Ca2CO3_1 % 12 h 0 1.96 38.66 0.23 0.041 0.0172 0.0032 5.33 50 2.05 20.33 0.14 0.0143 0.0137 0.001 13.67 100 2.5 10.33 0.13 0.012 0.0189 0.001767 11.51 200 0 0 0 0 0 0 0 24 h 0 1.81 31 0.24 0.032 0.0171 0.00213 8.66 50 2.11 24 0.20 0.009 0.0198 0.0015 13.54 100 2.13 22.66 0.14 0.019 0.0206 0.00233 8.88 200 1.83 7 0.13 0.010 0.0201 0.000967 20.81 Ca2CO3_2% 12 h 0 1.91 50.66 0.21 0.034 0.0169 0.0026 6.62 50 2.46 28.66 0.21 0.030 0.0253 0.00246 10.54 100 3.03 14.33 0.12 0.012 0.0215 0.00213 10.44 200 0.66 1.66 0 0 0 0 0 24 h 0 1.879 39.33 0.28 0.034 0.0199 0.0025 7.88 50 2.45 40 0.22 0.039 0.0196 0.003 6.65 100 2.21 20.66 0.16 0.014 0.0239 0.0017 14.47 200 2.33 6.33 0.09 0.013 0.0203 0.0010 19.11 LSD 5 % - - 1.34 10.59 0.05 0.005 0.0048 0.0006 8.0855 MGT: Mean Germination Time, GI: Germination Index, FShM: Fresh Shoot Mass, FRM: Fresh Root Mass, DShMW: Dry Shoot Mass, DRM: Dry Root Mass, Sh/R: Shoot/Root ratio Acta agriculturae Slovenica, 118/2 – 2022 13 Comprehensive seed priming assessment of Hibiscus sabdariffa L. in germination and seedling growth stage under salt stress and hydro-prime in 50 mM salinity condition (Table 4). Seed priming is one of the simple, low risk and cost ap- proaches used to cope with the adverse effect of salin- ity in agricultural lands. The privilege of seed priming or pretreatment in unfavorable conditions have been studied in several crops, instance hot pepper (Khan et al., 2009), tomato (Ebrahimi et al., 2014), pepper (Aloui et al., 2014), lettuce (Nasri et al., 2011), pea (Pisum sa- tivum L.) (Naz et al., 2014), and maize (Abraha & Yo- hannes, 2013). Soil salinity has adverse effects on agri- culture productivity. Therefore, agronomic and genetic solutions to enhancing salt tolerance are urgently re- quired. We concluded that applying easy and low-cost techniques such as priming can remarkably increase the germination seed in salinity condition. 4 CONCLUSIONS Priming is a technique that is capable to improve the performance of seeds in salinity stress conditions. Under saline condition, 24 h 2 % Ca2CO3 had the high- est germination percentage (43.3 %) in 50 mM, while 12 h treatment with 0.5 % Na2SO3 (33.3 %) had high ger- mination percentage in 100 mM levels of saline condi- tions. Also, the highest germination rate index was ob- served in 0.5 % Na2SO3 with 12 h treatment time (4.05 and 3.95 respectively) in 50 and 100 mM levels of saline conditions. There was no geminated seed at 24 h prim- ing by 0.5 and 1 percentage of KNO3, while priming with 1 % of KNO3 at 12 h showed good performance in terms of shoot mass trait under saline condition. The result of various priming on studied traits revealed the importance of the type of priming compound and priming duration. The result implied that the best treat- ments in terms of GP were 12 h hydropriming, 24 h Ca2CO3_2 %, 12 h Na2SO3_0.5 %, 24 h Ca2CO3_1 %, in control, 50 mM salinity, 100 mM salinity, and 200 mM salinity conditions, respectively. We suggested perform- ing the same studies with the suitable material at the precise concentration on similar species to determine and understand the reliability and efficiency of the ap- proaches. Also, supplementary research should concen- trate on molecular, metabolic, and physiological stimu- late with priming agents in salt stress. Moreover, future studies need to assess germination and early seedling growth at the field condition. 5 ACKNOWLEDGMENTS This research was conducted in a research project (No. 99.3821) at University of Hormozgan. The authors are thankful to Minab Higher Education Center, Uni- versity of Hormozgan to provide laboratory facilities and equipment. 6 REFERENCES Abdollahi, F., & Jafari, L. (2012). Effect of NaCl and KNO3 priming on seed germination of canola (Brassica Napus L.) under salinity conditions. International Journal of Ag- riculture, Research and Review, 2, 573–579. Abraha, B., & Yohannes, G. (2013). 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