Morphophysiology of yellow passion fruit seedlings under application of nitrogen and potassium and irrigation with high-salinity water

Abstract

Salinity is one of the most problematic abiotic stresses in agriculture globally, especially in semi-arid regions. Thus, the application of nutrients, such as nitrogen and potassium to improve plant nutritional conditions may be a viable alternative to minimize the negative effects of saline stress. Therefore, the aim of this study was to evaluate the morphophysiological behavior of yellow passion fruit seedlings under varying nitrogen and potassium doses and irrigation with salt water. The experimental design was a randomized complete block with a 5 x 5 incomplete factorial scheme, generated from the Central Composite Design with five electrical conductivities of irrigation water (0.5, 0.98, 2.15, 3.32, and 3. 80 dS m-1) and five increasing doses of nitrogen and potassium (0.0, 29.08, 100.0, 170.92, and 200.0%). Leaf, stem, and root dry phytomass and gas exchange were evaluated 75 days after sowing. The increase in salinity had negative effects on the morphological and physiological characteristics of yellow passion fruit seedlings. The application of nitrogen and potassium positively influenced photosynthetic rate and leaf and root dry phytomasses. The application of nitrogen and potassium increased intercellular CO2 concentration and transpiration in yellow passion fruit seedlings under saline stress.

Gas exchange and yield of grafted yellow passion fruit under salt stress and plastic mulching

“…In the soil without mulching, irrigation with high-salinity water increased the WUE from 3.98 to 4.75 mmol CO 2 mol -1 H 2 O in yellow passion fruit propagated by seeds and from 2.53 to 4.88 mmol CO 2 mol -1 CO 2 in yellow passion fruit grafted on P. cincinnata, representing increments of 19.3 and 92.9%, respectively (Figure 3B). These results corroborate those observed by Figueiredo et al (2020), who found that the yellow passion fruit plant irrigated with saline water increased its WUE, leading to the conclusion that the crop has a certain tolerance to salt stress due to the maintenance, to a certain extent, of carbon assimilation.…”

“…Yellow passion fruit (Passiflora edulis f. flavicarpa Deneger) is an economically important fruit for Brazil and especially for the Northeast region, where 71.2% of Brazilian passion fruit was harvested in 2020 (IBGE, 2021). In this region, the soil and climate conditions are favorable to the exploitation of the crop, with the exception of rain (Figueiredo et al, 2020), so irrigation is required, and the available water sources naturally contain high levels of soluble salts (Moura et al, 2020).…”

“…Under salt stress, plants have physiological limitations due to the reduction in water availability resulting from the decrease in the osmotic potential of the soil, which affects the efficiency of CO 2 assimilation (Negrão et al, 2017;Ren et al, 2021) and, consequently, reduces crop yield (Figueiredo et al, 2020;Lima et al, 2020). In this context, studies have shown that Passifloraceae species native to the semi-arid region have mechanisms of tolerance to salt stress, such as osmotic adjustment and stomatal regulation (Moura et al, 2020), and propagation by grafting could be a viable alternative in the production of yellow passion fruit (Veimrober Junior et al, 2022).…”

Effect of saline stress, and nitrogen and potassium fertilization on morphophysiology of Passiflora edulis Sims. f. flavicarpa Dreg.

“…Saline stress affects the accumulation of phytomass, limiting the absorption of water and essential nutrients, with immediate effects on cell growth and expansion (Nóbrega et al, 2022). Figueiredo et al (2020) observed the influence of high salinity on dry phytomass in passion fruit plants.…”

“…Based on this context, the increase in LMR observed in this work can be explained by the greater fraction of material retained in the leaves, i.e., the lower export of photoassimilates from the leaves to the other parts of the plant (Silva et al, 2021). The increase in LMR under increasing levels of saline water was described by Silva et al (2023) for Ocimum basilicum L., and under doses of nitrogen and potassium by Figueiredo et al (2020) for Passiflora edulis.…”