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

Abstract

The production of soursop seedlings in the Northeast region of Brazil has faced limitations due to the high concentrations of salts in the water, so it is necessary to use techniques that enable its cultivation, and the application of hydrogen peroxide to minimize the deleterious effects of salt stress stands out. In this context, the objective was to evaluate forms of application of hydrogen peroxide as an attenuator of salt stress on the gas exchange and growth of soursop seedlings cv. Morada Nova. The experiment was conducted under greenhouse conditions, in an Regolithic Neosol of sandy loam texture, from the municipality of Lagoa Seca - PB. A completely randomized design was used in a 5 × 4 factorial arrangement, whose treatments resulted from the combination of five levels of electrical conductivity of irrigation water - ECw (0.6 – control, 1.2, 1.8, 2.4 and 3.0 dS m-1) and four forms of hydrogen peroxide application (M1 - without H2O2 application, M2 - application by seed soaking, M3 - application by foliar spraying, and M4 - application by seed soaking + foliar spraying), with four replicates and two plants per experimental unit, totaling 160 plants. The concentration of H2O2 used in the different forms of application was 20 µM. Irrigation water salinity from 0.6 dS m-1 reduced the gas exchange and growth of soursop. The method of H2O2 application by foliar spraying minimized the effects of salt stress on gas exchange. The method of H2O2 application by seed soaking reduced the effect of salt stress on the growth of soursop at 85 days after sowing.

Morphophysiology of soursop under salt stress and H2O2 application in the pre-flowering phase

“…The results found in this study for gs are in agreement with those obtained by Veloso et al (2022), who, in an assay with soursop cv. Morada Nova (ECw from 0.7 to 3.7 dS m -1 ), found a reduction of 37.93% in plants subjected to the highest ECw compared to those that received the lowest ECw.…”

“…Plants subjected to a concentration of 30 μM stood out with the highest WSD value (60.76%), with an increase of 14.40% compared to plants that were not subjected to H 2 O 2 (0 μM). A similar result was found by Silva et al (2022), who studied the effect of hydrogen peroxide in the attenuation of salt stress on physiological indicators and growth of soursop in the seedling formation phase and observed an increase in WSD in plants subjected to the H 2 O 2 concentration of 30 μM.…”

“…Studies have highlighted the deleterious effects of salinity on fruit crops (Veloso et al, 2022;Capitulino et al, 2022). Veloso et al (2022), when evaluating gas exchange and growth of soursop under salt stress (ECw from 0.7 to 3.7 dS m -1 ), verified that this crop is sensivel to the salinity of the irrigation water from 0.7 dS m -1 , which compromised the gas exchange, absolute growth rates of plant height and stem diameter, and relative growth rate of plant height in soursop at 120 days after transplanting.…”

Mineral composition and production of guava under salt stress and salicylic acid

“…High levels of salts in water and/or soil alter plant physiology and growth and limit production due to osmotic and ionic effects (Capitulino et al, 2022). The reduction in the osmotic potential of the soil has as a main consequence the decrease in the availability of water to plants, inducing more significant energy expenditure to maintain metabolic activities (Andrade et al, 2019).…”

Physiology and production of sugar-apple under water stress and application of proline

“…Obstacles to the expansion of production areas in the Brazilian semi-arid region include rainfall irregularity and high evapotranspiration rate, which results in limitations to adequate water availability during the crop cycle, leading to production losses and changes in fruit quality (Lima et al, 2015;Capitulino et al, 2022;Pinheiro et al, 2022a). The sugar-apple is tolerant to conditions of water deficiency (Fernandes et al, 2022), however, the sensitivity of plants to stress varies according to the stages of development (Ferreira et al, 2022).…”