Condicionamento de sementes de pitaia (Hylocereus Costaricensis) como atenuante do estresse salino na germinação e crescimento inicial.

Abstract

Dragon fruit cultivation has been gaining prominence in several states in the semi-arid region of Northeast Brazil, where some abiotic stresses are present and tend to limit the productivity of many crops. The use of exogenous substances has been used to mitigate abiotic stresses in plants. The present proposal aimed to evaluate the influence of conditioning factors on the physiological performance of dragon fruit seeds subjected to saline stress. The experiment was conducted in a completely randomized design in a 5 x 6 factorial scheme, corresponding to five pre-germination treatments (distilled water, gibberellic acid, salicylic acid, Thiamethoxam and Quicelum®) and six saline concentrations (0; 1.0; 2. 0; 3.0; 4.0 and 5.0 dS.m-1) using four replications of 50 seeds per treatment. Physiological evaluations were carried out: percentage of germination, germination speed index, length of aerial part and main root of seedlings and total dry mass and biochemistry of total soluble sugar content. Analysis of variance was carried out using the F test with 5% significance with means of the qualitative variable compared using the Tukey test (p≤0.05), while the means of the quantitative variable were subjected to polynomial regression analysis. The use of conditioning agents, as well as salinity, did not influence the germination of the dragon fruit, the dragon fruit is resistant to salinity. Salicylic acid, Quicelum® and Thiamethoxam stimulated vigor, favoring rapid germination of dragon fruit seeds in salinity of up to 3 dS.m-1. Gibberellic acid, salicylic acid and Thiamethoxam guarantee good phytomass formation at saline levels of up to 2.5 dS.m-1. Gibberellic acid, salicylic acid, Quicelum® and Thiamethoxam improve the physiological performance of dragon fruit seeds under saline stress conditions.