Quality of soursop (Annona muricata L.) seedlings under different water salinity levels and nitrogen fertilization

Abstract

The edaphoclimatic characteristics of the Brazilian Northeast region favor the exploitation of soursop, a crop that is appreciated by the population of the whole country. However, due to the water limitation in this region, it is necessary to study techniques that make saline water feasible in the cultivation of the species. The present study aimed to evaluate phytomass production and quality of soursop cv. 'Morada Nova' seedlings, irrigated with waters of different salinity levels and fertilized with nitrogen (N) doses. The experiment was carried out in a greenhouse at the Center of Sciences and Agri-food Technology of the Federal University of Campina Grande (Pombal-PB), using a randomized block experimental design, in 5 x 4 factorial scheme, which corresponded to five levels of water electrical conductivity-ECw (0.3; 1.1; 1.9; 2.7 and 3.5 dS m-1) and four N doses (70, 100, 130 and 160 mg of N dm-3 of soil), with four replicates and two plants per plot. At 90 days after applying the treatments, the following variables were evaluated to assess the quality of the seedlings: fresh and dry phytomass of stem and leaves, dry phytomass of shoots (aerial parts), roots and total, and Dickson's quality index. Irrigation water with ECw of up to 2.0 dS m-1 allows the production of soursop seedlings, cv. 'Morada Nova', with acceptable reduction of growth. The N dose of 70 mg dm-3 stimulates phytomass production and quality of the seedlings. There was no significant interaction between the factors on the studied variables of seedlings at 90 days after application of the treatments. Water of 2.0 dS m-1 associated with nitrogen fertilization using 70 mg of urea dm-3 of soil should be used in the formation of soursop seedlings.

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

“…In the semi-arid region of northeastern Brazil, soursop cultivation is limited, because the water available for irrigation commonly contains high concentrations of salts resulting from high evaporation and low precipitation, which reduces the quality of this resource for use in agriculture (Veloso et al, 2018;Sá et al, 2018).…”

Gas exchanges in sugar apple (Annona squamosa L.) subjected to salinity stress and nitrogen fertilization

“…Bezerra et al (2014) state that nutritionally balanced plants have greater resistance to environmental stresses, thus an adequate fertilization is needed in order to improve plant resistance against stress conditions. In this sense, nitrogen is one of the most required essential nutrient, due to its several functions on plant metabolism, being an important component of chlorophyll, amino acids and proteins (Veloso et al, 2018). When an adequate amount of nitrogen is supplied, the plant photosynthetic capacity is stimulated, due to an increase in stromal proteins and thylakoids in leaf chloroplasts (Akram et al, 2011).…”

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

“…According to Oliveira et al (2013), DQI is an important morphological characteristic used to determine the quality and rusticity of the seedlings, because it expresses the growth capacity and balance in the distribution of biomass under stress conditions. Veloso et al (2018), when evaluating the quality of soursop seedlings cv. 'Morada Nova', irrigated with waters of different salinity levels (ECw from 0.3 to 3.5 dS m -1 ) prepared with salts of Na + , Ca 2+ , and Mg 2+ in the proportion of 7:2:1 also found that plants under ECw up to 3.5 dS m -1 had DQI higher than 0.2, is characterized as seedlings of good quality for field transplanting.…”

“…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).…”