Formação de mudas de goiabeira sob irrigação com água salina e métodos de aplicação de H2O2.

Abstract

Due to the socioeconomic importance of the guava tree for the Northeast region of Brazil, together with the high concentration of salts present in the region's waters and their deleterious effects on most crops, it is necessary to use technologies that mitigate these effects of saline stress on the plants, such as the application of elicitors, such as hydrogen peroxide, but there are few studies that evaluate the best form of application. Therefore, the objective of this research was to evaluate ways of applying hydrogen peroxide to guava seedlings irrigated with saline water. The experimental design used was randomized blocks, in a 5 × 4 factorial scheme, with five levels of electrical conductivity of irrigation water - CEw (0.3; 1.1; 1.9; 2.7 and 3.5 dS m -1) and four methods of application of hydrogen peroxide (M1 - without application of H2O2, M2 - application via seed soaking, M3 - application via foliar spray and M4 - application via seed soaking + foliar spray), at a concentration of 20 μM of H2O2, with three replications and two plants per plot, totaling 120 experimental units. The effects of the treatments were evaluated 120 days after transplanting, using growth and physiological parameters and phytomass accumulation. Salinity reduced the growth, dry mass accumulation and relative water content of guava cv. paluma. Foliar application of H2O2 attenuated the deleterious effect of water salinity on guava seedlings in the leaf area, total dry matter and aerial part up to conductivity of 2.7 dS m-1. The application of seed + foliar imbibition increases the number of leaves, dry mass of leaves and dry phytomass of the aerial part in guava cv seedlings. paluma irrigated with water of 3.5 dS m-1.