Silício como atenuante do estresse salino na formação de mudas de cultivares de maracujazeiro-amarelo

Abstract

In the passion fruit production chain, the production of quality seedlings is a fundamental step, as it significantly contributes to the uniformity of plantations in the field. However, the available water often has high salt content, which hinders seedling formation. A promising alternative for mitigating salt stress is silicon supplementation, but more research is needed to elucidate the mechanisms involved in silicon action and to optimize its application in different production systems. This study was carried out to evaluate the effects of silicon application methods on mitigating saline stress in yellow passion fruit cultivars. An experiment was conducted in a greenhouse, using a completely randomized design, in a 2 x 2 x 4 factorial scheme, with five replications. The factors studied were two yellow passion fruit cultivars (BRS Sol do Cerrado and BRS Gigante Amarelo), two levels of electrical conductivity of irrigation water (1.2 and 4.0 dS m-1) and four methods of silicon application (control without application, soil application, foliar application and combined application - 50% soil and 50% foliar). Two silicon applications were made: the first at 12 days after transplanting and the second at 27 days after transplanting. At 60 days after sowing, growth, biomass, gas exchange, cell status and nutrient accumulation variables in the plants were evaluated. The results obtained indicated that the cultivar BRS Sol do Cerrado showed better tolerance to salinity, while BRS Gigante Amarelo showed greater benefit from silicon application, especially in foliar and combined (soil + foliar) forms. In general, silicon application improved seedling quality, promoting better growth, increased relative leaf water content, reduced electrolyte leakage, and better instantaneous water use efficiency under saline stress conditions. Silicon supplementation proved promising in mitigating the effects of saline stress, promoting better absorption of several essential nutrients. However, the response of plants to silicon was complex, varying according to genotype and application method.