Indução de tolerância com ácido salicílico em maracujazeiro-azedo irrigado com águas de diferentes composições catiônicas

This study aimed to evaluate the physiological indices, growth, and seedling quality of the sour passion fruit cv. BRS SC1 as a function of irrigation with water of different cationic natures and exogenous application of salicylic acid. The experiment was conducted under plant nursery conditions at the CCTA/UFCG, Campus Pombal-PB, using a randomized block design set up in a 6 × 4 factorial arrangement referring to six cationic compositions of irrigation water (S1 – control, S2 - Na+, S3 - Ca2+, S4 - Na+ + Ca2+, S5 - Mg2+, and S6 - Na+ + Ca2+ + Mg2+) and four concentrations of salicylic acid - SA (0, 1.0, 2.0, and 3.0 mM), with three replications and two plants per plot. In the control treatment (S1), the plants were irrigated with the electrical conductivity level of 0.3 dS m-1, whereas the other treatments (S2, S3, S4, S5, and S6) used water with 4.0 dS m-1 obtained based on different cations, all in the form of chloride. The exogenous application of salicylic acid increased the content of chlorophyll b in the sour passion fruit seedlings. Salt stress negatively affected seedling growth. Seedling quality was affected by the electrical conductivity of irrigation water regardless of the cationic nature. Although showing reductions, the seedlings produced under high salinity showed a satisfactory Dickson quality index. The genotype cv. BRS SC1 is considered tolerant to salinity when irrigated with water salinized by Na+, Ca2+, Na+ + Ca2+, and Na+ + Ca2+ + Mg2+, and moderately tolerant when irrigated with water salinized by Mg2+.Objetivou-se avaliar os índices fisiológicos, o crescimento, e a qualidade de mudas de maracujazeiro-azedo ‘BRS SC1’ em função da irrigação com águas de diferentes naturezas catiônicas e aplicação exógena de ácido salicílico. O experimento foi conduzido sob condições de casa de vegetação, pertencente ao CCTA/UFCG, Campus de Pombal-PB, utilizando-se o delineamento de blocos casualizados com arranjo fatorial 6 × 4, sendo seis composições catiônicas da água de irrigação (S1 - Testemunha; S2 - Na+; S3 - Ca2+; S4 - Na+ + Ca2+; S5 - Mg2+ e S6 - Na+ + Ca2+ + Mg2+), e quatro concentrações de ácido salicílico - AS (0; 1,0; 2,0 e 3,0 mM) com três repetições e duas plantas por parcela. Na testemunha (S1), as plantas foram irrigadas com água de condutividade elétrica de 0,3 dS m-1 enquanto se utilizou, nos demais tratamentos (S2; S3; S4; S5 e S6) água com 4,0 dS m-1, obtida a partir de diferentes cátions, todos em forma de cloreto. A aplicação exógena de ácido salicílico aumentou o teor de clorofila b nas mudas de maracujazeiro-azedo. O estresse salino afetou negativamente o crescimento das plantas de maracujazeiro. A qualidade das mudas foi afetada pela condutividade elétrica da água, independente da natureza catiônica. Apesar de causar redução, as mudas produzidas sob elevado nível salino apresentou índice satisfatórios. O genótipo ’BRS SC1’ é considerado tolerante à salinidade quando irrigado com água salinizada por Na+; Ca2+; Na+ + Ca2+; Na+ + Ca2+ + Mg2+, e moderadamente tolerante quando irrigado com água salinizada por Mg2+

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

This research aimed to evaluate the effects of salt stress, varying the phenological stages, and K fertilization on NPK concentrations, physiology, and production of Passiflora edulis Sims. The research was carried out at the University Farm of São Domingos, Paraíba, Brazil, using a randomized block design with a 6 × 2 factorial arrangement. Six irrigation strategies were evaluated (use of low electrical conductivity water (0.3 dS m−1) during all stages of development and application of high-salinity water (4.0 dS m−1) in the following stages: vegetative, flowering, fruiting, successively in the vegetative/flowering, and vegetative/fruiting stages) and two potassium levels (207 and 345 g K2O per plant), with four replications and three plants per plot. The leaf concentrations of N, P, and K in the sour passion fruit plants found in the present study were below the optimal levels reported in the literature, regardless of the development stage and the cultivation cycle. The relative water content, stomatal conductance, and photosynthesis were reduced by salt stress in the first cycle. However, in the second cycle, irrigation with 4.0 dS m−1 in the vegetative/flowering stages increased the CO2 assimilation rate. Passion fruit is sensitive to salt stress in the vegetative/flowering stages of the first cycle. In the second cycle, salt stress in the fruiting stage resulted in higher production per plant