Gas Exchange and Production of Passion Fruit as Affected by Cationic Nature of Irrigation Water1

Abstract

Yellow passion fruit is a fruit species widely cultivated throughout the Brazilian semi-arid territory, but its yield is affected by the quality of the waters of this region. In this context, the objective was to evaluate the gas exchange and production of passion fruit cv. BRS Rubi do Cerrado irrigated with waters of different cationic natures. The study was conducted in drainage lysimeters under greenhouse conditions in Campina Grande, PB, Brazil, in a randomized block design, and the treatments were eight cationic natures of irrigation water (S1 - Control; S2 - Na+; S3 - Ca2+; S4 - Mg2+; S5 - Na+ + Ca2+; S6 - Na+ + Mg2+; S7 - Ca2+ + Mg2+ and S8 - Na+ + Ca2+ + Mg2+) with three replicates. Plants in the control treatment were irrigated with water of low electrical conductivity (ECw = 0.4 dS m-1), while those of the other treatments were irrigated using water with ECw of 3.5 dS m-1. The treatments Na+ + Ca2+, Na+ + Mg2+ and Ca2+ + Mg2+ were prepared in the equivalent ratio of 1:1, and Na++Ca2++Mg2+ in the ratio 7:2:1, respectively. Water salinity of 3.5 dS m-1 reduced gas exchange, and stomatal conductance and transpiration were the most sensitive variables of passion fruit. The number of fruits of passion fruit cv. BRS Rubi do Cerrado decreased with water salinity, regardless of the cationic nature. The waters of calcic and calcic+magnesian nature caused the greatest deleterious effects on the production variables of passion fruit, at 259 days after transplanting.

Formation of guava seedlings under irrigation with water of different cationic natures and salicylic acid

“…On the other hand, the partial closure of the stomata observed in this study through stomatal conductance (Figure 2A) contributes to reducing water losses by transpiration to the atmosphere in plants subjected to irrigation with water containing Na + (S2) Ca 2+ (S3), Na + +Ca 2+ (S4), Mg 2+ (S5) and Na + +Ca 2+ +Mg 2+ (S6), but does not compromise CO 2 diffusion in the leaf mesophyll (LIMA et al, 2020), as observed by the internal CO 2 concentration data (Figure 3B), and plays an important physiological function in the maintenance of osmotic and ionic homeostasis in the plant (MOHAMED et al, 2020). Paiva et al (2021), in a study evaluating the effects of irrigation with waters of different cationic natures (S1 -Control; S2 -Na + ; S3 -Ca 2+ ; S4 -Mg 2+ ; S5 -Na + + Ca 2+ ; S6 -Na + + Mg 2+ ; S7 -Ca 2+ + Mg 2+ and S8 -Na + + Ca 2+ + Mg 2+ ) on the gas exchange of passion fruit cv 'BRS Rubi do Cerrado', found the lowest values of leaf transpiration when plants were irrigated with water salinized by calcium (S3) and magnesium (S4) and observed no significant difference between plants that received the treatments S2, S5, S6, S7, and S8.…”

“…In addition, the salts absorbed by plants and accumulated in the photosynthetically active mesophyll tissues can inhibit CO 2 assimilation, mainly affecting photosynthesis processes in chloroplasts, standing out as a non-stomatal limitation. The alterations include inhibition of the activity of photosynthetic enzymes of the Calvin cycle, disturbance in chlorophyll biosynthesis, and reduction in operational efficiency and structural integrity of the photosynthetic apparatus and thylakoid membranes (PAN et al, 2021).…”

“…In regions with adverse climatic conditions, especially in semi-arid areas, low rainfall and intense evaporation are common in most months of the year, and water sources usually have high salt levels, especially in crystalline areas, with high amounts of chloride and sodium, low concentrations of sulfate, and varying concentrations of calcium, magnesium, carbonates, and bicarbonates (SILVA JÚNIOR; GHEYI; MEDEIROS, 1999;PAIVA et al, 2021;PINHEIRO et al, 2022). On the other hand, in some parts, such as the Apodi Plateau (Rio Grande do Norte/Ceará), Gurgueia (Piauí) and Iracema (Bahia), there is a predominance of calcium/magnesium salts (HOLANDA et al, 2016).…”

NPK Accumulation, Physiology, and Production of Sour Passion Fruit under Salt Stress Irrigated with Brackish Water in the Phenological Stages and K Fertilization

“…Furthermore, excessive ion concentrations in the soil solution also damage photosynthetically active leaves and can result in chlorosis and early senescence, thus negatively affecting photosynthetic efficiency and production [ 4 ]. In this context, several studies have been carried out evaluating the effects of irrigation with saline water in the passion fruit crop, highlighting changes in gas exchange [ 5 ], photochemical efficiency [ 6 ], synthesis of photosynthetic pigments [ 7 ], and membrane instability [ 8 ], as well as a reduction in production components [ 9 , 10 ] and post-harvest quality [ 11 ]. However, these studies are restricted to the use of water with different levels of salinity throughout the plant development cycle, thus requiring further research, especially to assess the effects of salt stress on the accumulation of NPK, physiology, and production of sour passion fruit plants of the cultivar BRS GA1, one of the most commonly grown in northeast Brazil, at varying phenological stages.…”

“…In this context, several studies have been carried out evaluating the effects of irrigation with saline water in the passion fruit crop, highlighting changes in gas exchange [ 5 , 22 ], photochemical efficiency [ 6 ], synthesis of photosynthetic pigments [ 7 ], and membrane instability [ 8 ], as well as a reduction in production components [ 9 , 10 ] and post-harvest quality [ 11 ]. However, these studies are restricted to the use of water with different levels of electrical conductivity throughout the plant development cycle, thus requiring further research, especially to assess the concentrations of NPK, physiology, and production of Passiflora edulis Sims, cultivar BRS GA1, grown under salt stress in the phenological stages and fertilization with K.…”