Growth and gas exchanges in soursop under irrigation with saline water and nitrogen sources

Abstract

Nitrogen (N) fertilization has been tested for the mitigation of salt stress in some species including fruit crops. However, special attention should be paid to the source of N, due to the different compositions and saline indices of the fertilizers, particularly when irrigation is conducted using waters with salinity levels that are restrictive to agriculture. Thus, this study evaluated the effect of fertilization with N sources on the growth and gas exchanges of soursop irrigated with saline water after transplanting. The experiment was carried out in greenhouse at the Center of Technology and Natural Resources of the Federal University of Campina Grande, and treatments were arranged in randomized blocks, in 4 x 4 factorial scheme, corresponding to electrical conductivity of water - 0.5, 1.1, 2.5 and 3.5 dS m-1, and the N sources urea, ammonia sulfate, calcium nitrate and potassium nitrate, with three replicates. Growth and gas exchanges of soursop at 110 days after transplanting were not influenced by either the interaction between water salinity and N sources or the individual action of N, but were inhibited by the increase in water salinity from 0.5 dS m-1. Increasing water salinity inhibited stomatal opening and carboxylation in the leaves.

Growth and gas exchange of West Indian cherry irrigated with saline waters under combinations of nitrogen-potassium fertilization

“…Lower transpiration caused by salinity increase ( Figure 4B) was due the decrease in stomatal opening ( Figure 4A), which consequently decreased water losses to the atmosphere in vapor form; and also restricted the CO 2 entry into the cells, resulting in a lower rate of CO 2 assimilation ( Figure 4C), as already verified in soursop plants (Silva et al, 2018).…”

Métodos de aplicação de peróxido de hidrogênio em mudas de gravioleira irrigadas com água salina

“…The salinity levels used in this research were based on studies performed by Silva et al (2019b). The H 2 O 2 concentration used was 20 µM, as established in the research performed by Silva et al (2018).…”

“…The interest for this fruit species has grown due to its several food and pharmaceutical uses, preventing a series of chronic-degenerative disorders (Dauda et al, 2018). However, soursop cultivation in the semiarid region has been limited due to the salinity of the water used in irrigation (Silva et al, 2018).…”

Salicylic Acid as an Attenuator of Salt Stress in Soursop

“…Excess salts in water inhibit plant growth due to some factors such as toxicity of ions (Na + and Cl -), osmotic and oxidative stress, degradation of pigments, alteration of metabolic pathways, and inhibition of photosynthesis and nutrient absorption (BISTGANI et al, 2019;MAGALHÃES et al, 2020). Silva et al (2018), studying the growth and gas exchange of soursop seedlings under irrigation with saline water, found that water salinity from 0.5 dS m -1 negatively affected their gas exchange and growth. Reductions in soursop growth due to the increase in the salinity level of irrigation water were also identified by Veloso et al (2019).…”