Brassinosteroids Confer Tolerance to Salt Stress in Eucalyptus urophylla Plants Enhancing Homeostasis, Antioxidant Metabolism and Leaf Anatomy
- 161 Downloads
The sodium ion (Na+) is potentially toxic to plants because it can cause K+/Na+ imbalances, oxidative stress and negatively affect growth. Brassinosteroids (BRs), including 24-epibrassinolide (EBR), is an organic substance, biodegradable and positively contributes to plant metabolism. The aim of this research was to investigate whether EBR application via the leaves can enhance homeostasis and to examine the impacts of EBR on the anatomical, physiological, biochemical and morphological behaviours of young Eucalyptus urophylla plants exposed to salt stress. The experiment had four treatments: two salt conditions (0 and 250 mM NaCl, described as − Na+ and + Na+, respectively) and two concentrations of 24-epibrassinolide (0 and 50 nM EBR, described as − EBR and + EBR, respectively). The results suggest that EBR mitigated the deleterious effects caused by salt stress in young E. urophylla plants, thereby improving homeostasis related to the K+/Na+ ratio and increasing the nutrient contents of the tissues. Plants exposed to both Na+ and EBR showed increases in photosynthetic pigments and photochemical efficiency. This result may be a result of the antioxidant system, specifically, the significant increases in the CAT (20%) and APX (51%) enzymes, which were comparable to plants receiving equal treatment without Na+. Additionally, this steroid had benefits for gas exchange and growth that were associated with leaf anatomy and were confirmed by increases in stomatal density (23%), palisade parenchyma (14%) and spongy parenchyma (25%). Therefore, our results confirm that the exogenous application of EBR resulted in tolerance to salt stress.
KeywordsAscorbate peroxidase Gas exchange Salinity Stomatal performance 24-Epibrassinolide
This research had financial supports from Fundação Amazônia de Amparo a Estudos e Pesquisas (FAPESPA/Brazil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/Brazil) and Universidade Federal Rural da Amazônia (UFRA/Brazil) given to AKSL. In other hand, VPO was supported with scholarships from Programa de Educação Tutorial (PET/Brazil).
AKSL was the advisor of this project, planning all phases of this research. VPO and MDRL conducted the experiment in the greenhouse and performed physiological, biochemical and morphological determinations, while BRSS measured anatomical parameters and BLB performed nutritional determinations and helped in drafting the manuscript and in interpreting the results.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no competing interests.
- Ali Q, Athar HUR, Ashraf M (2006b) Influence of exogenously applied brassinosteroids on the mineral nutrient status of two wheat cultivars grown under saline conditions. Pak J Bot 38:1621–1632Google Scholar
- Aragão RM, Silva EN, Vieira CF, Silveira JAG (2012) High supply of NO3—mitigates salinity effects through an enhancement in the efficiency of photosystem II and CO2 assimilation in Jatropha curcas plants. Acta Physiol Plant 34:2135–2143. https://doi.org/10.1007/s11738-012-1014-y CrossRefGoogle Scholar
- Cakmak I, Horst WJ (1991) Effect of aluminium on lipid peroxidation, superoxide dismutase, catalase, and peroxidase activities in root tips of soybean (Glycine max). Physiol Plant 83:463–468. https://doi.org/10.1111/j.1399-3054.1991.tb00121.x CrossRefGoogle Scholar
- Castro EM, Pereira FJ, Paiva R (2009) Histologia vegetal: estrutura e função dos órgãos vegetativos. UFLA, LavrasGoogle Scholar
- Cha-um S, Somsueb S, Samphumphuang T, Kirdmanee C (2013) Salt tolerant screening in eucalypt genotypes (Eucalyptus spp.) using photosynthetic abilities, proline accumulation, and growth characteristics as effective indices. Vitr Cell Dev Biol Plant 49:611–619. https://doi.org/10.1007/s11627-013-9537-5 CrossRefGoogle Scholar
- FAO (2017) Food and Agriculture Organization of the United Nation. FAO, RomeGoogle Scholar
- Hoagland DR, Arnon DI (1950) The water-culture method for growing plants without soil, 2nd edn. California Agricultural Experiment StationGoogle Scholar
- Jabeen Z, Hussain N, Han Y et al (2014) The differences in physiological responses, ultrastructure changes, and Na + subcellular distribution under salt stress among the barley genotypes differing in salt tolerance. Acta Physiol Plant 36:2397–2407. https://doi.org/10.1007/s11738-014-1613-x CrossRefGoogle Scholar
- Karlidag H, Yildirim E, Turan M (2011) Role of 24-epibrassinolide in mitigating the adverse effects of salt stress on stomatal conductance, membrane permeability, and leaf water content, ionic composition in salt stressed strawberry (Fragaria × ananassa). Sci Hortic 130:133–140. https://doi.org/10.1016/j.scienta.2011.06.025 CrossRefGoogle Scholar
- Kiliç S, Çavusogly K, Kabar K (2007) Effects of 24-epibrassinolide on salinity stress induced inhibition of seed germination, seedling growth and leaf anatomy of barley. SDU Fac Arts Sci J Sci 2:41–52Google Scholar
- Kumar R, Goyal V, Kuhad MS (2005) Influence of fertility-salinity interactions on growth, water status and yield of Indian mustard (Brassica juncea). Indian J Plant Physiol 10:139–144Google Scholar
- Lichtenthaler HK, Buschmann C (2001) Chlorophylls and carotenoids: measurement and characterization by UV-VIS spectroscopy. In: Current protocols in food analytical chemistry. Wiley, Hoboken, pp 431–438Google Scholar
- Munns R, Tester M (2008) Mechanisms of salinity tolerance. Annu Rev Plant Biol 59:651–681. https://doi.org/10.1146/annurev.arplant.59.032607.092911 CrossRefGoogle Scholar
- Nakano Y, Asada K (1981) Hydrogen peroxide is scavenged by ascorbate-specific peroxidase in spinach chloroplasts. Plant Cell Physiol 22:867–880Google Scholar
- Shahbaz M, Ashraf M (2007) Influence of exogenous application of brassinosteroid on growth and mineral nutrients of wheat (Triticum Aestivum L.) under saline conditions. Pak J Bot 39:513–522Google Scholar
- Silva EN, Ribeiro RV, Ferreira-Silva SL et al (2012) Coordinate changes in photosynthesis, sugar accumulation and antioxidative enzymes improve the performance of Jatropha curcas plants under drought stress. Biomass Bioenergy 45:270–279. https://doi.org/10.1016/j.biombioe.2012.06.009 CrossRefGoogle Scholar
- Sivakumar R, Pathamanaban G, Kalarani MK et al (2002) Effect of foliar application of miyobi growth regulators on morpho-physiological attributes and yield in chili. Indian J Plant Physiol 7:79–82Google Scholar
- Steel RG, Torrie JH, Dickey DA (2006) Principles and procedures of statistics: a biometrical approach, 3rd edn. Academic Internet Publishers, MoorparkGoogle Scholar
- Talaat NB, Shawky BT (2013) 24-Epibrassinolide alleviates salt-induced inhibition of productivity by increasing nutrients and compatible solutes accumulation and enhancing antioxidant system in wheat (Triticum aestivum L.). Acta Physiol Plant 35:729–740. https://doi.org/10.1007/s11738-012-1113-9 CrossRefGoogle Scholar
- Wu X, Zhu Z, Li X, Zha D (2012) Effects of cytokinin on photosynthetic gas exchange, chlorophyll fluorescence parameters and antioxidative system in seedlings of eggplant (Solanum melongena L.) under salinity stress. Acta Physiol Plant 34:2105–2114. https://doi.org/10.1007/s11738-012-1010-2 CrossRefGoogle Scholar
- Zhu J-K (2002) Salt and drought stress signal transduction in plants. Annu Rev Plant Biol 53:247–273. https://doi.org/10.1146/annurev.arplant.53.091401.143329 CrossRefGoogle Scholar