Induction of tolerance to salt stress in soursop seedlings using hydrogen peroxide

Abstract

The exogenous use of hydrogen peroxide is an alternative in the acclimatization of plants to salt stress due to the greater activity of antioxidant enzymes. In this perspective, this study aimed to evaluate the gas exchange and the growth of soursop seedlings under salt stress using hydrogen peroxide. The study was conducted under greenhouse conditions. The treatments were distributed in randomized blocks, in a 5 x 2 factorial arrangement, related to five levels of electrical conductivity of the irrigation water - ECw (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) and two concentrations of hydrogen peroxide - H2O2 (0 and 20 μM), with four replicates and two plants per plot. The effects of the treatments were evaluated by the variables of gas exchange and growth. The increase in water salinity negatively affected the gas exchange and the growth of the soursop seedlings. The gas exchange and growth variables presented deleterious effects caused by the salinity of the irrigation water, mitigated by the exogenous application of hydrogen peroxide at the concentration of 20 μM. The exogenous use of hydrogen peroxide at the concentration of 20 μM can be used to induce salt tolerance in soursop seedlings.

Gas exchange and growth of soursop under salt stress and H2O2 application methods

“…53, 4.06, 3.43, 3.11, and 2.72 mm) were obtained with the method of application via seed soaking at salinity levels of 0.6, 1.2, 1.8, 2.4, and 3.0 dS m -1 , respectively. Silva et al (2019a) concluded that pre-treatment of seeds with H 2 O 2 attenuates the deleterious effects of irrigation water salinity on the stem diameter of soursop cv. 'Morada Nova' at 110 days after sowing a result similar to that found in this study.…”

“…In this context, several studies have evaluated the effects of hydrogen peroxide as an attenuator of salt stress, such as that of Silva et al (2016), who found that the application of H 2 O 2 in concentrations of 7 to 8 µM at Hydrogen peroxide attenuates salt stress in soursop seedlings application by foliar spraying and M4 -application by seed soaking + foliar spraying), in a 5 × 4 factorial arrangement, distributed in a completely randomized design, with four replicates and two plants per experimental unit, totaling 160 plants. The salinity levels used here were based on studies conducted by Silva et al (2019a).…”

Leaf Gas Exchange and Flowering of Mango Sprayed With Biostimulant in Semi-Arid Region

“…SV 1 Stomatal conductance averages were 0.03 and 0.09 mol m -2 s -1 at the pre-flowering and fullflowering, respectively (Table 2). When the plant is put under stresses, the tendency is that the stomata close and, as a result, there is a reduction of transpiration to achieve a minimal loss of the water contained in the plant (SILVA et al, 2019). In addition, Schaffer et al (2009) infer that stomatal conductance is the main factor to control the net photosynthesis in mango trees, including with linear and exponential relations between these variables, due to a decrease in CO 2 supply to the mesophyll cells caused by stomatal closure, resulting in lower net photosynthetic rate (LAXMAN; ANNAPOORNAMMA; BIRADAR, 2016).…”

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

“…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). 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.…”