Soil salinity is severely affecting crop productivity in many countries, particularly in the Mediterranean area. To evaluate early plant responses to increased salinity and characterize tolerance markers, three important Brassica crops - Chinese cabbage (Brassica rapa ssp. pekinensis), white cabbage (B. oleracea var. capitata) and kale (B. oleracea var. acephala) were subjected to short-term (24 h) salt stress by exposing them to NaCl at concentrations of 50, 100, or 200 mM. Physiological (root growth, photosynthetic performance parameters, and Na+/K+ ratio) and biochemical parameters (proline content and lipid peroxidation as indicated by malondialdehyde, MDA, levels) in the plants' roots and leaves were then measured. Photosynthetic parameters such as the total performance index PItotal (describing the overall efficiency of PSI, PSII and the intersystem electron transport chain) appeared to be the most salinity-sensitive parameter and informative stress marker. This parameter was decreased more strongly in Chinese cabbage than in white cabbage and kale. It indicated that salinity reduced the capacity of the photosynthetic system for efficient energy conversion, particularly in Chinese cabbage. In parallel with the photosynthetic impairments, the Na+/K+ ratio was highest in Chinese cabbage leaves and lowest in kale leaves while kale root is able to keep high Na+/K+ ratio without a significant increase in MDA. Thus Na+/K+ ratio, high in root and low in leaves accompanying with low MDA level is an informative marker of salinity tolerance. The crops' tolerance was positively correlated with levels of the stress hormone abscisic acid (ABA) and negatively correlated with levels of jasmonic acid (JA), and jasmonoyl-L-isoleucine (JA-Ile). Furthermore, salinity induced contrasting changes in levels of the growth-promoting hormones brassinosteroids (BRs). The crop's tolerance was positively correlated with levels of BR precursor typhasterol while negatively with the active BR brassinolide. Principal Component Analysis revealed correlations in observed changes in phytohormones, biochemical, and physiological parameters. Overall, the results show that kale is the most tolerant of the three species and Chinese cabbage the most sensitive to salt stress, and provide holistic indications of the spectrum of tolerance mechanisms involved.

Department of Biology Josip Juraj Strossmayer University of Osijek Osijek Croatia

Department of Molecular Biology Ruđer Bošković Institute Zagreb Croatia

Division of Botany Department of Biology Faculty of Science University of Zagreb Zagreb Croatia

Faculty of Dental Medicine and Health Josip Juraj Strossmayer University of Osijek Osijek Croatia

Faculty of Humanities and Social Sciences Josip Juraj Strossmayer University of Osijek Osijek Croatia

Laboratory of Growth Regulators Institute of Experimental Botany The Czech Academy of Sciences Palacký University Olomouc Czechia

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Ahmad P., Rasool S., Gul A., Sheikh S. A., Akram N. A., Ashraf M., et al. (2016). Jasmonates: multifunctional roles in stress tolerance. Front. Plant Sci. 7:813. 10.3389/fpls.2016.00813 PubMed DOI PMC

Almeida D. M., Margarida Oliveira M., Saibo N. J. M. (2017). Regulation of Na+ and K+ homeostasis in plants: towards improved salt stress tolerance in crop plants. Genet. Mol. Biol. 40 326–345. 10.1590/1678-4685-GMB-2016-0106 PubMed DOI PMC

Almeida P., Feron R., de Boer G. J., de Boer A. H. (2014). Role of Na+, K+, Cl-, proline and sucrose concentrations in determining salinity tolerance and their correlation with the expression of multiple genes in tomato. AoB Plants 6:plu039. 10.1093/aobpla/plu039 PubMed DOI PMC

Ashraf M., Harris P. J. C. (2013). Photosynthesis under stressful environments: an overview. Photosynthetica 51 163–190. 10.1111/plb.12014 PubMed DOI

Assaha D. V. M., Ueda A., Saneoka H., Al-Yahyai R., Yaish M. W. (2017). The role of Na+ and K+ transporters in salt stress adaptation in glycophytes. Front. Physiol. 8:509 10.3389/fphys.2017.00509 PubMed DOI PMC

Begović L., Mlinarić S., Dunić J. A., Katanić Z., Lončarić Z., Lepeduš H., et al. (2016). Response of Lemna minor L. to short-term cobalt exposure: the effect on photosynthetic electron transport chain and induction of oxidative damage. Aquat. Toxicol. 175 117–126. 10.1016/j.aquatox.2016.03.009 PubMed DOI

Chakraborty K., Sairam R. K., Bhattacharya R. C. (2012). Differential expression of salt overly sensitive pathway genes determines salinity stress tolerance in Brassica genotypes. Plant Physiol. Biochem. 51 90–101. 10.1016/j.plaphy.2011.10.001 PubMed DOI

Chen S., Yang J., Zhang M., Strasser R. J., Qiang S. (2016). Classification and characteristics of heat tolerance in Ageratina adenophora populations using fast chlorophyll a fluorescence rise O-J-I-P. Environ. Exp. Bot. 122 126–140. 10.1016/j.envexpbot.2015.09.011 DOI

Dabrowski P., Baczewska A. H., Pawluśkiewicz B., Paunov M., Alexantrov V., Goltsev V., et al. (2016). Prompt chlorophyll a fluorescence as a rapid tool for diagnostic changes in PSII structure inhibited by salt stress in Perennial ryegrass. J. Photochem. Photobiol. B Biol. 157 22–31. 10.1016/j.jphotobiol.2016.02.001 PubMed DOI

Duan H., Zhu Y., Qi D., Li W., Hua X., Liu Y., et al. (2012). Comparative study on the expression of genes involved in carotenoid and ABA biosynthetic pathway in response to salt stress in tomato. J. Integr. Agr. 11 1093–1102. 10.1016/S2095-3119(12)60102-6 DOI

Duarte B., Cabrita M. T., Gameiro C., Matos A. R., Godinho R., Marques J. C., et al. (2017). Disentangling the photochemical salinity tolerance in Aster tripolium L.: connecting biophysical traits with changes in fatty acid composition. Plant Biol. 19 239–248. 10.1111/plb.12517 PubMed DOI

Ellouzi H., Ben Hamed K., Hernández I., Cela J., Müller M., Magné C., et al. (2014). A comparative study of the early osmotic, ionic, redox and hormonal signaling response in leaves and roots of two halophytes and a glycophyte to salinity. Planta 240 1299–1317. 10.1007/s00425-014-2154-7 PubMed DOI

Fahad S., Hussain S., Matloob A., Khan F. A., Khaliq A., Suad S., et al. (2015). Phytohormones and plant responses to salinity stress: a review. Plant Growth Regul. 75 391–404. 10.1007/s10725-014-0013-y DOI

Fiket Ž., Mikac N., Kniewald G. (2016). Mass fractions of forty-six major and trace elements, including rare earth elements, in sediment and soil reference materials used in environmental studies. Geostand. Geoanal. Res. 41 123–135. 10.1111/ggr.12129 DOI

Finkelstein R. (2013). Abscisic acid synthesis and response. Arabidopsis Book 11:e0166. 10.1199/tab.0166 PubMed DOI PMC

Floková K., Tarkowská D., Miersch O., Strnad M., Wasternack C., Novák O. (2014). UHPLC-MS/MS based target profiling of stress-induced phytohormones. Phytochemistry 105 147–157. 10.1016/j.phytochem.2014.05.015 PubMed DOI

Geng Y., Wu R., Wee C. W., Xie F., Wei X., Chan P. M. Y., et al. (2013). A spatio-temporal understanding of growth regulation during the salt stress response in Arabidopsis. Plant Cell 25 2132–2154. 10.1105/tpc.113.112896 PubMed DOI PMC

Gharbi E., Martínez J. P., Benahmed H., Hichri I., Dobrev P. I., Motyka V., et al. (2017). Phytohormone profiling in relation to osmotic adjustment in NaCl-treated plants of the halophyte tomato wild relative species Solanum chilense comparatively to the cultivated glycophyte Solanum lycopersicum. Plant Sci. 258 77–89. 10.1016/j.plantsci.2017.02.006 PubMed DOI

Goltsev V., Kalaji H., Paunov M., Baba W., Horaczek T., Mojski J., et al. (2016). Variable chlorophyll fluorescence and its use for assessing physiological condition of plant photosynthetic apparatus. Russ. J. Plant Physiol. 63 869–893. 10.1134/S1021443716050058 DOI

González-García M. P., Vilarrasa-Blasi J., Zhiponova M., Divol F., Mora-Garcia S., Russinova E., et al. (2011). Brassinosteroids control meristem size by promoting cell cycle progression in Arabidopsis roots. Development 138 849–859. 10.1242/dev.057331 PubMed DOI

Ha Y., Shang Y., Nam K. H. (2016). Brassinosteroids modulate ABA-induced stomatal closure in Arabidopsis. J. Exp. Bot. 67 6297–6308. 10.1093/jxb/erw385 PubMed DOI PMC

Han J. Y., Kim Y. S., Hwang O. J., Roh J., Ganguly K., Kim S. K., et al. (2017). Overexpression of Arabidopsis thaliana brassinosteroid-related acyltransferase 1 gene induces brassinosteroid-deficient phenotypes in creeping bentgrass. PLoS One 12:e0187378. 10.1371/journal.pone.0187378 PubMed DOI PMC

Hazman M., Hause B., Eiche E., Nick P., Riemann M. (2015). Increased tolerance to salt stress in OPDA-deficient rice ALLENE OXIDE CYCLASE mutants is linked to an increased ROS-scavenging activity. J. Exp. Bot. 66 3339–3352. 10.1093/jxb/erv142 PubMed DOI PMC

Jajoo A. (2014). “Changes in photosystem II heterogeneity in response to high salt stress,” in Contemporary Problems of Photosynthesis, eds Allakhverdiev S. I., Rubin A. B., Shuvalov V. A. (Izhevsk-Moscow: Institute of Computer Science; ), 397–413.

Jan A. S., Shinwari Z. K., Rabbani M. A. (2016). Morpho-biochemical evaluation of Brassica rapa sub-species for salt tolerance. Genetika 48 323–338. 10.2298/GENSR1601323J DOI

Jiroutova P., Okleskova J., Strnad M. (2018). Crosstalk between brassinosteroids and ethylene during plant growth and under abiotic stress conditions. Int. J. Mol. Sci. 19:E3283. 10.3390/ijms19103283 PubMed DOI PMC

Julkowska M. M., Testerink C. (2015). Tuning plant signaling and growth to survive salt. Trend Plant Sci. 20 586–594. 10.1016/j.tplants.2015.06.008 PubMed DOI

Kalaji H. M., Bosa K., Kościelniak J., Żuk-Gołaszewska K. (2011). Effects of salt stress on photosystem II efficiency and CO2 assimilation of two Syrian barley landraces. Environ. Exp. Bot. 73 64–72. 10.1016/j.envexpbot.2010.10.009 DOI

Kalaji H. M., Račková L., Paganová V., Swoczyna T., Rusinowski S., Sitko K. (2017). Can chlorophyll a fluorescence parameters be used as bio-indicators to distinguish between drought and salinity stress in Tilia cordata mill? Environ. Exp. Bot. 152 149–157. 10.1016/j.envexpbot.2017.11.001 DOI

Kamboj A., Ziemann M., Bhave M. (2015). Identification of salt-tolerant barley varieties by a consolidated physiological and molecular approach. Acta Physiol. Plant. 37:1716 10.1007/s11738-014-1716-4 DOI

Krüger G. H. J., De Villiers M. F., Strauss A. J., de Beer M., van Heerden P. D. R., Maldonado R., et al. (2014). Inhibition of photosystem II activities in soybean (Glycine max) genotypes differing in chilling sensitivity. S. Afr. J. Bot. 95 85–96. 10.1016/j.sajb.2014.07.010 DOI

Kumar G., Purty R. S., Sharma M. P., Singla-Pareek S. L., Pareek A. (2009). Physiological responses among Brassica species under salinity stress show strong correlation with transcript abundance for SOS pathway-related genes. J. Plant Physiol. 166 507–520. 10.1016/j.jplph.2008.08.001 PubMed DOI

Kurotani K. I., Hayashi K., Hatanaka S., Toda Y., Ogawa D., Ichikawa H., et al. (2015). Elevated levels of CYP94 family gene expression alleviate the jasmonate response and enhance salt tolerance in rice. Plant Cell Physiol. 56 779–789. 10.1093/pcp/pcv006 PubMed DOI

Liang W., Ma X., Wan P., Liu L. (2018). Plant salt-tolerance mechanism: a review. Biochem. Biophys. Res. Commun. 495 286–291. 10.1016/j.bbrc.2017.11.043 PubMed DOI

Mancarella S., Orsini F., Van Oosten M. J., Sanoubar R., Stanghellini C., Kondo S., et al. (2016). Leaf sodium accumulation facilitates salt stress adaptation and preserves photosystem functionality in salt stressed Ocimum basilicum. Environ. Exp. Bot. 130 162–173. 10.1016/j.envexpbot.2016.06.004 DOI

Mehta P., Jajoo A., Mathur S., Bharti S. (2010). Chlorophyll a fluorescence study revealing effects of high salt stress on photosystem II in wheat leaves. Plant Physiol. Biochem. 48 16–20. 10.1016/j.plaphy.2009.10.006 PubMed DOI

Mittal S., Kumari N., Sharma V. (2012). Differential response of salt stress on Brassica juncea: photosynthetic performance, pigment, proline, D1 and antioxidant enzymes. Plant Physiol. Biochem. 54 17–26. 10.1016/j.plaphy.2012.02.003 PubMed DOI

Munns R., Gilliham M. (2015). Salinity tolerance of crops - what is the cost? New Phytol. 208 668–673. 10.1111/nph.13519 PubMed DOI

Munns R., James R. A., Gilliham M., Flowers T. J., Colmer T. D. (2016). Tissue tolerance: an essential but elusive trait for salt-tolerant crops. Funct. Plant Biol. 43 1103–1113. 10.1071/FP16187 PubMed DOI

Northey J. G., Liang S., Jamshed M., Deb S., Foo E., Reid J. B., et al. (2016). Farnesylation mediates brassinosteroid biosynthesis to regulate abscisic acid responses. Nat. Plants 2:16114. 10.1038/nplants.2016.114 PubMed DOI

Oklestkova J., Tarkowská D., Eyer L., Elbert T., Marek A., Smržová Z., et al. (2017). Immunoaffinity chromatography combined with tandem mass spectrometry: a new tool for the selective capture and analysis of brassinosteroid plant hormones. Talanta 170 432–440. 10.1016/j.talanta.2017.04.044 PubMed DOI

Oukarroum A., Bussotti F., Goltsev V., Kalaji H. M. (2015). Correlation between reactive oxygen species production and photochemistry of photosystems I and II in Lemna gibba L. plants under salt stress. Environ. Exp. Bot. 109 80–88. 10.1016/j.envexpbot.2014.08.005 DOI

Pavlović I., Pěnčík A., Novák O., Vujčić V., Radić Brkanac S., Lepeduš H., et al. (2018a). Short-term salt stress in Brassica rapa seedlings causes alterations in auxin metabolism. Plant Physiol. Biochem. 125 74–84. 10.1016/j.plaphy.2018.01.026 PubMed DOI

Pavlović I., Petřik I., Tarkowská D., Lepeduš H., Vujčić Bok V., Radić Brkanac S., et al. (2018b). Correlations between phytohormones and drought tolerance in selected Brassica crops: Chinese cabbage, white cabbage and kale. Int. J. Mol. Sci. 19:2866. 10.3390/ijms19102866 PubMed DOI PMC

Pedranzani H., Racagni G., Alemano S., Miersch O., Ramírez I., Peña-Cortés H., et al. (2003). Salt tolerant tomato plants show increased levels of jasmonic acid. Plant Growth Regul. 4 149–158. 10.1080/15592324.2016.1146847 PubMed DOI PMC

Per T. S., Khan M. I. R., Anjum N. A., Masood A., Hussain S. J., Khan N. A. (2018). Jasmonates in plants under abiotic stresses: crosstalk with other phytohormones matters. Environ. Exp. Bot. 145 104–120. 10.1016/j.envexpbot.2017.11.004 DOI

Puniran-Hartley N., Hartley J., Shabala L., Shabala S. (2014). Salinity-induced accumulation of organic osmolytes in barley and wheat leaves correlates with increased oxidative stress tolerance: in planta evidence for cross-tolerance. Plant Physiol. Biochem. 83 32–39. 10.1016/j.plaphy.2014.07.005 PubMed DOI

Purty R. S., Kumar G., Singla-Pareek S. L., Pareek A. (2008). Towards salinity tolerance in Brassica: an overview. Physiol. Mol. Biol. Plants 14 39–49. 10.1007/s12298-008-0004-4 PubMed DOI PMC

Radić S., Cvjetko P., Glavaš K., Roje V., Pevalek-Kozlina B., Pavlica M. (2009). Oxidative stress and DNA damage in broad bean (Vicia faba L.) seedlings induced by thallium. Environ. Toxicol. Chem. 28 189–196. 10.1897/08-188.1 PubMed DOI

Raja V., Majeed U., Kang H., Andrabi K. I., John R. (2017). Abiotic stress: interplay between ROS, hormones and MAPKs. Environ. Exp. Bot. 137 142–157. 10.1016/j.envexpbot.2017.02.010 DOI

Riemann M., Dhakarey R., Hazman M., Miro B., Kohli A., Nick P. (2015). Exploring jasmonates in the hormonal network of drought and salinity. Front. Plant Sci. 6:1077. 10.3389/fpls.2015.01077 PubMed DOI PMC

Schansker G., Tóth S. Z., Holzwarth A. R., Garab G. (2014). Chlorophyll a fluorescence: beyond the limits of the QA model. Photosyn. Res. 120 43–58. 10.1007/s11120-013-9806-5 PubMed DOI

Shannon M. C., Grieve C. M. (1999). Tolerance of vegetable crops to salinity. Sci. Hortic. 78 5–38. 10.1016/S0304-4238(98)00189-7 DOI

Sharma I., Kaur N., Pati P. K. (2017). Brassinosteroids: a promising option in deciphering remedial strategies for abiotic stress tolerance in rice. Front. Plant Sci. 8:2151. 10.3389/fpls.2017.02151 PubMed DOI PMC

Siddiqui H., Hayat S., Bajguz A. (2018). Regulation of photosynthesis by brassinosteroids in plants. Acta Physiol. Plant. 40:59 10.1007/s11738-018-2639-2 DOI

Soshinkova T. N., Radyukina N. L., Korolkova D. V., Nosov A. V. (2013). Proline and functioning of the antioxidant system in Thellungiella salsuginea plants and cultured cells subjected to oxidative stress. Russ. J. Plant Physiol. 60 41–54. 10.1134/S1021443713010093 DOI

Strasser R. J., Srivastava A., Tsimilli-Michael M. (2000). “The Fluorescence transient as a tool to characterize and screen photosynthetic samples,” in Probing Photosynthesis: Mechanism, Regulation and Adaptation, eds Yunus M., Pathre U., Mohanty P. (New York, NY: CRC; ), 445–483.

Strasser R. J., Tsimilli-Michael M., Srivastava A. (2004). “Analysis of the chlorophyll a fluorescence transient,” in Chlorophyll a Fluorescence: A Signature of Photosynthesis, eds Papageorgiou G. C., Govinjee (Dordrecht: Springer; ), 321–362. 10.1007/978-1-4020-3218-9_12 DOI

Strizhov N., Abrahám E., Okrész L., Blickling S., Zilberstein A., Schell J., et al. (1997). Differential expression of two P5CS genes controlling proline accumulation during salt-stress requires ABA and is regulated by ABA1, ABI1 and AXR2 in Arabidopsis. Plant J. 12 557–569. 10.1046/j.1365-313X.1997.00557.x PubMed DOI

Surender Reddy P., Jogeswar G., Rasineni G. K., Maheswari M., Reddy A. R., Varshney R. K., et al. (2015). Proline over-accumulation alleviates salt stress and protects photosynthetic and antioxidant enzyme activities in transgenic sorghum [Sorghum bicolor (L.) Moench]. Plant Physiol. Biochem. 94 104–113. 10.1016/j.plaphy.2015.05.014 PubMed DOI

Tani T., Sobajima H., Okada K., Chujo T., Arimura S. I., Tsutsumi N., et al. (2008). Identification of the OsOPR7 gene encoding 12-oxophytodienoate reductase involved in the biosynthesis of jasmonic acid in rice. Planta 227 517–526. 10.1007/s00425-007-0635-7 PubMed DOI

Tomek P., Lazár D., Ilík P., Naus J. (2001). On the intermediate steps between the O and P steps in chlorophyll a fluorescence rise measured at different intensities of exciting light. Funct. Plant Biol. 28 1151–1160. 10.1071/PP01065 DOI

Venkatesh J., Upadhyaya C. P., Yu J.-W., Hemavathi A., Kim D. H., Strasser R. J., et al. (2012). Chlorophyll a fluorescence transient analysis of transgenic potato overexpressing D-galacturonic acid reductase gene for salinity stress tolerance. Hortic. Environ. Biotechnol. 53 320–328. 10.1007/s13580-012-0035-1 DOI

Verma V., Ravindran P., Kumar P. P. (2016). Plant hormone-mediated regulation of stress responses. BMC Plant Biol. 16:86. 10.1186/s12870-016-0771-y PubMed DOI PMC

Verslues P. E., Bray E. A. (2006). Role of abscisic acid (ABA) and Arabidopsis thaliana ABA-insensitive loci in low water potential-induced ABA and proline accumulation. J. Exp. Bot. 57 201–212. 10.1093/jxb/erj026 PubMed DOI

Wang Y., Mopper S., Hasenstein K. H. (2001). Effects of salinity on endogenous ABA, IAA, JA, and SA in Iris hexagona. J. Chem. Ecol. 27 327–342. 10.1023/A:1005632506230 PubMed DOI

Wasternack C., Strnad M. (2016). Jasmonate signaling in plant stress responses and development - active and inactive compounds. N. Biotechnol. 33 604–613. 10.1016/j.nbt.2015.11.001 PubMed DOI

Witzel K., Matros A., Strickert M., Kaspar S., Peukert M., Mühling K. H., et al. (2014). Salinity stress in roots of contrasting barley genotypes reveals time-distinct and genotype-specific patterns for defined proteins. Mol. Plant 7 336–355. 10.1093/mp/sst063 PubMed DOI

Yusuf M. A., Kumar D., Rajwanshi R., Strasser R. J., Tsimilli-Michael M., Govindjeeet al. (2010). Overexpression of g-tocopherol methyl transferase gene in transgenic Brassica juncea plants alleviates abiotic stress: physiological and chlorophyll a fluorescence measurements. Biochim. Biophys. Acta 1797 1428–1438. 10.1016/j.bbabio.2010.02.002 PubMed DOI

Zeng H., Tang Q., Hua X. (2010). Arabidopsis brassinosteroid mutants det2-1 and bin2-1 display altered salt tolerance. J. Plant Growth Regul. 29 44–52. 10.1007/s00344-009-9111-x DOI

Zhang X., Lu G., Long W., Zou Y., Li F., Nishio T. (2014). Recent progress in drought and salt tolerance studies in Brassica crops. Breed. Sci. 64 60–73. 10.1270/jsbbs.64.60 PubMed DOI PMC

Zhu M., Zhou M., Shabala L., Shabala S. (2017). Physiological and molecular mechanisms mediating xylem Na+ loading in barley in the context of salinity stress tolerance. Plant Cell Environ. 40 1009–1020. 10.1111/pce.12727 PubMed DOI

Żurek G., Rybka K., Pogrzeba M., Krzyżak J., Prokopiuk K. (2014). Chlorophyll a fluorescence in evaluation of the effect of heavy metal soil contamination on Perennial grasses. PLoS One 9:e91475. 10.1371/journal.pone.0091475 PubMed DOI PMC

Zushi K., Matsuzoe N. (2017). Using of chlorophyll a fluorescence OJIP transients for sensing salt stress in the leaves and fruits of tomato. Sci. Hortic. 219 216–221. 10.1016/j.scienta.2017.03.016 DOI

Contents of endogenous brassinosteroids and the response to drought and/or exogenously applied 24-epibrassinolide in two different maize leaves

Involvement of Phenolic Acids in Short-Term Adaptation to Salinity Stress is Species-Specific among Brassicaceae