Salt-tolerance induced by leaf spraying with H2O2 in sunflower is related to the ion homeostasis balance and reduction of oxidative damage

Abstract

Salinity is still one of the main factors that limit the growth and production of crops. However, currently, hydrogen peroxide (H 2 O 2) priming has become a promising technique to alleviate the deleterious effects caused by salt. Therefore, this study aimed to test different leaf spraying strategies with H 2 O 2 for acclimation of sunflower plants to salt stress, identifying the main physiological and biochemical changes involved in this process. The experiment was conducted in a completely randomized design, with four replications. Initially, four concentrations of H 2 O 2 were tested (0.1; 1; 10 and 100 mM) associated with different applications: 1AP-one application (48 h before exposure to NaCl); 2AP-two applications (1AP þ one application 7 days after exposure to NaCl) and 3AP-three applications (2AP þ one application 14 days after exposure to NaCl), besides this two reference treatments were also added: control (absence of NaCl and absence of H 2 O 2) and salt control (presence of 100 mM of NaCl and absence of H 2 O 2). The experiment was conducted in hydroponic system containing Furlani's nutrient solution. Salt stress reduced the growth of sunflower plants, however, the H 2 O 2 priming through leaf spraying was able to reduce the deleterious effects caused by salt, especially in the 1 mM H 2 O 2 treatment with one application. H 2 O 2 acts as a metabolic signal assisting in the maintenance of ionic and redox homeostasis, and consequently increasing the tolerance of plants to salt stress.

Transcriptomic Profiling Provides Molecular Insights Into Hydrogen Peroxide-Enhanced Arabidopsis Growth and Its Salt Tolerance

“…Seedling treatment with inorganic and organic agents greatly reduces the detrimental effects of stress and enhances essential nutrient content ( Qiu et al, 2014 ; Cantabella et al, 2017 ; Ghassemi-Golezani and Farhangi-Abriz, 2018 ; Silva et al, 2020 ; Zahedi et al, 2021 ). In our present work, the pretreatment of seedlings with H 2 O 2 increased the fresh and dry weights of salinity-treated seedlings.…”

“…Several studies have shown that the pretreatment of plants with exogenous H 2 O 2 can significantly increase abiotic stress tolerance. For example, pretreatment of H 2 O 2 protected Arabidopsis thaliana leaves against excess light damage ( Karpinski et al, 1999 ), induced the adaptation of rice seedlings to salt stress and high temperature ( Uchida et al, 2002 ), improved the salt resistances of barley ( Fedina et al, 2009 ), maize ( Gondim et al, 2012 ) and sunflower ( Silva et al, 2020 ), enhanced the chilling tolerance of the two Zoysia cultivars Manila grass ( Zoysia matrella ) and Mascarene grass ( Zoysia tenuifolia ) ( Wang et al, 2010 ), induced salt stress acclimation in maize plants ( De Azevedo Neto et al, 2005 ), and alleviates drought stress in soybean plants ( Ishibashi et al, 2011 ). The pretreatment of wheat seeds with H 2 O 2 also enhanced the subsequent drought ( He et al, 2009 ) and salt ( Wahid et al, 2007 ) resistances of the seedlings.…”

Physiological, nutritional, and biochemical indicators of lead tolerance in sunflower genotypes

“…It has been shown that exposure to Pb reduces water uptake and transport in the roots, affecting the relative water content in plant tissue, thereby leading to the need to maintain cell turgor (Rucińska-Sobkowiak et al, 2013). Soluble carbohydrates and free amino acids are considered the main organic compounds involved in osmotic adjustment (Silva et al, 2020). As the increase in these compounds was observed only in the roots of Pb-sensitive genotypes, the results suggest that the energy cost for osmoregulation through the synthesis of the organic compounds was higher in the H251 and AG963 genotypes than in the BRS-G27.…”

Cationic Nature of Water and Hydrogen Peroxide on the Formation of Passion Fruit Seedlings1

“…Silva et al (2019a), in a study evaluating the induction of tolerance to salt stress in soursop seedlings using H 2 O 2 , observed that the deleterious effects of water salinity on gas exchange and growth of soursop were mitigated by the exogenous application of H 2 O 2 . In another study, Silva et al (2020) concluded that foliar spraying of H 2 O 2 increased the tolerance of sunflower plants to salt stress, mainly due to the balance of ionic homeostasis and redox. In this context, the objective of this study was to evaluate the water relations, photosynthetic pigments, and growth of passion fruit cv.…”

“…Among the alternatives that can be used to attenuate the stress caused by salinity on plants, the exogenous application of hydrogen peroxide -H 2 O 2 stands out (VELOSO et al, 2018;SILVA et al, 2019a;SILVA et al, 2020). H 2 O 2 can act as a key regulator in modulating the defense response of plants to salt stress, as its electrochemical characteristics enable it to cross membranes and spread between cell compartments, which facilitates its signaling function (SILVA et al, 2020). At low concentrations, H 2 O 2 regulates metabolism, cooperating with other hormones and signaling molecules, and confers tolerance to stress (SMIRNOFF; RNAUD, 2019).…”