Effects of saline water and exogenous application of hydrogen peroxide (H2O2) on Soursop (Annona muricata L.) at vegetative stage

Abstract

Soursop is a fruit of great socioeconomic importance for the northeastern region of Brazil. However, the quantitative and qualitative limitation of the water resources of this region has reduced its production. The objective of this study was to evaluate the growth of ‘Morada Nova’ soursop plants irrigated with saline water and subjected to exogenous application of hydrogen peroxide through seed immersion and foliar spray. The study was conducted in plastic pots adapted as lysimeters, using a eutrophic Regolithic Neosol with sandy loam texture under greenhouse conditions. Treatments were distributed in randomized blocks, in a 4 x 4 factorial arrangement, corresponding to four levels of irrigation water electrical conductivity – ECw (0.7; 1.7; 2.7 and 3.7 dS m-1) and four concentrations of hydrogen peroxide – H2O2 (0, 25, 50 and 75 µM), with three replicates and one plant per plot. Foliar applications of H2O2 began 15 days after transplanting (DAT) and were carried out every 15 days at 17:00 h, after the sunset, by manually spraying the H2O2 solutions with a sprayer in such a way to completely wet the leaves (spraying the abaxial and adaxial faces). Treatment effects were evaluated based on plant height (PH), stem diameter (SD), number of leaves (NL) and leaf area (LA) at 60 and 90 DAT, and dry phytomass of leaves (LDP), stem (SDP), roots (RDP) and total (TDP) and leaf succulence (LS) at 90 DAT. Irrigation using water with estimated ECw of 1.55 dS m-1 caused acceptable mean reduction of 10% in soursop growth. Increasing concentrations of hydrogen peroxide did not attenuate the effects of salinity on plant height and leaf area during the vegetative stage. Hydrogen peroxide concentration of 20 µM led to higher leaf succulence in soursop plants.

Gas Exchange, Chloroplast Pigments and Growth of Passion Fruit Cultivated With Saline Water and Potassium Fertilization 1

“…Reduction in leaf area stands out as a mechanism of tolerance of plants to salt stress and an alternative to maintain cell turgor, reducing water losses by transpiration and, consequently, reducing the transport of toxic ions such as Na + and Clin the xylem (OLIVEIRA et al, 2011). Studies conducted with soursop (VELOSO et al, 2019) and guava…”

Cultivation of Custard-Apple Irrigated With Saline Water Under Combinations of Nitrogen, Phosphorus and Potassium

“…Regarding the salts applied via irrigation water, part accumulates in the soil while another part is absorbed by the plants and the rest is adsorbed in the soil colloids with the potential to increase the concentration, especially after successive applications, reaching the point of reducing the availability of water to the plants, due to the effect of osmotic nature and consequently, inducing stomatal closure, limiting transpiration, which reduces the rate of photosynthesis, causing a decrease in crop production (DIAS et al, 2018;VELOSO et al, 2019).…”

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

“…The reduction in biomass accumulation by passion fruit plants is also related to the osmotic effect caused by the high concentrations of salts in the root zone, promoting changes in ionic and osmotic homeostasis, thus causing a reduction in growth and, consequently, in biomass accumulation (SÁ et al, 2019). Veloso et al (2019), when evaluating the growth of 'Morada Nova' soursop plants irrigated with saline water (ECw ranging from 0.3 to 3.7 dS m -1 and with Na:Ca:Mg in the equivalent proportion of 7:2:1), also observed a reduction in the accumulation of stem dry biomass as water salinity levels increased.…”