Pré-exposição ao peróxido de hidrogênio na tolerância de mudas de goiabeira ao estresse salino.

Abstract

The Northeast region of Brazil is the largest producer of guava tree and has great socioeconomic importance, however the salinity of the water has been one of the restrictions on fruits production. However, management strategies can be adopted in order to attenuate salt stress, among them the exogenous application of hydrogen peroxide at low concentrations can minimize the deleterious effects of salts about plants. In this sense, the objective of this study was to verify whether the pre-exposure, through soaking of seeds to hydrogen peroxide, results in the acclimatization of 'Paluma' guava seedlings to saline stress. The research was carried out in a greenhouse, belonging to the Center for Science and Agro-Food Technology of the Federal University of Campina Grande (CCTA/UFCG), located in the city of Pombal, PB. The design used was randomized blocks in a 5 × 3 factorial arrangement, with five levels of electrical conductivity of irrigation water - ECa (0.3; 1.1; 1.9; 2.7 and 3.5 dS m-1) and three concentrations of hydrogen peroxide - H2O2 (0, 25 and 50 µM), with four replications and five plants per plot. Water salinity from 0.3 dS m-1 promoted a decrease in growth, relative water content, photosynthetic pigments, dry phytomass, Dickson's quality index and increased the water saturation deficit of guava seedlings 'Paluma' at 110 days after sowing. hydrogen peroxide at a concentration of 25 µM increases the emergence speed index of 'Paluma' guava seedlings at 110 after sowing. The deleterious effects of saline stress on carotenoids, chlorophyll a and chlorophyll b contents were not attenuated by the application of hydrogen peroxide.