Potassium Does Not Attenuate Salt Stress in Yellow Passion Fruit Under Irrigation Management Strategies

Abstract

The objective of this study was to evaluate the gas exchange, growth and production of yellow passion fruit cv. BRS GA1, as a function of irrigation management strategies with saline water and potassium doses. The experiment was conducted under field conditions in São Domingos, PB, Brazil. A randomized block design was used in a 6 * 2 factorial scheme. The treatments consisted of six strategies of irrigation with saline waters (irrigation with low-salinity water throughout the crop cycle - SE; irrigation with high-salinity water in the vegetative stage - VE; flowering stage - FL; fruiting stage - FR; in the successive vegetative/flowering stages - VE/FL; vegetative/fruiting stages - VE/FR) and two doses of potassium (100 and 130% of the K2O recommendation), with four replicates and four plants per plot. The 100% dose corresponded to 60 g of K 2O plant-1 year-1. The effects of using high-salinity water (3.2 dS m-1) alternated with low-salinity water (1.3 dS m-1) were evaluated in different stages of the cultivation cycle. Irrigation with saline water in the fruiting stage promoted an increase in intercellular CO2 concentration and decrease in CO2 assimilation, with effects of non-stomatal origin standing out as limiting factors of photosynthetic efficiency. The highest CO 2 assimilation rate in plants subjected to water salinity of 1.3 dS m-1 throughout the cycle resulted in increments in the number of fruits and in the production per plant of the passion fruit cv. BRS GA1.

Physiological responses of inoculated and uninoculated peanuts under saline stress

“…Saline stress causes several physiological and biochemical disorders, as it reduces the osmotic potential of the soil, reducing water absorption; furthermore, these excess salts in the plant tissue become toxic to the plant leading to a nutritional disorder (Pereira Filho et al, 2019;Lima et al, 2020).…”

Potassium and irrigation water salinity on the formation of sour passion fruit seedlings

“…Summary of the analysis of variance for plant height (PH), stem diameter (SD), leaf area (LA), dry biomass of leaf (LDB), stem (StDB), root (RDB), and total (TDB) and Dickson Quality Index (DQI) of the seedlings of sour passion fruit cv. BRS RC cultivated with saline waters and potassium doses at 60 days after sowing Lima et al (2020) also verified that there was no significant effect of the interaction between the sources of variation on gas exchange, growth and production.…”

Salicylic acid does not mitigate salt stress on the morphophysiology and production of hydroponic melon

“…When comparing plants that received ECns of 5.4 dS m -1 to those that received 2.1 dS m -1 in the absence of salicylic acid, a decrease in Ci of 28.49% was observed. The reduction in Ci associated with the decrease in stomatal conductance in melon plants under the highest ECns can be attributed not only to stomatal closure that restricts CO 2 diffusion in the substomatal chamber (Lima et al, 2020a) but also to impaired activity of ribulose-1,5-bisphosphate carboxylase oxygenase, which predisposes the photosynthetic apparatus to increased energy dissipation and negative regulation of photosynthesis when plants are subjected to salt stress (Silva et al, 2018). Melo et al (2017), in a study with bell pepper evaluating gas exchange and photosynthetic pigment contents as a function of irrigation with saline waters (ECw: 0, 1, 3, 5, 7, and 9 dS m -1 ), obtained a maximum value of 229.80 µmol CO 2 m -2 s -1 for the internal CO 2 concentration in plants irrigated with ECw of 3.0 dS m -1 .…”