Bactérias promotoras de crescimento em mudas micropropagadas de bananeira cv. Prata Catarina irrigadas com água salina

Abstract

The banana (Musa spp.) Is a fruit of high consumption in natura in Brazil and in the world, Brazil being the fourth largest world producer. Although widely produced, many banana orchards show low productivity due to multiple stresses, including the use of moderately saline water, since it is a classified crop with low tolerance to salinity. In this context, the use of plant growth promoting bacteria (PGPB’s) appears as a promising alternative to mitigate biotic and abiotic stresses in plants. Thus, the study aimed to evaluate the use of strains of bacteria of the genus Bacillus sp. in acclimatization and initial development of banana seedlings cultivar Prata Catarina irrigated with saline water. In the first phase of the research, the growth of micropropagated seedlings was evaluated during acclimatization in a nursery and it was found that the use of Bacillus sp. strains 186 and 109 did not promote growth of banana seedlings cultivar Prata Catarina. On the other hand, strain 109 promoted an increase in leaf nitrogen content and strain 186 increased potassium and magnesium content in the roots. In the second phase, the effects of irrigation water salinity on banana seedlings cultivar Prata Catarina were inoculated with strains of Bacillus sp., with different levels of salinity. These levels caused reductions in growth parameters and gas exchange, regardless of the use of Bacillus sp.186 and 109 strains. Regarding nutrition, salinity influenced the levels of leaf and root nutrients, with an accumulation of of K + and Mg ++ above accumulation of Na +, which may be a tolerance mechanism of the species. In the third phase evaluated the effects of bacteria on the growth and ecophysiology of banana cultivar Prata Catarina irrigated with saline water. It was found that the increase in salinity negatively influenced the number of leaves, leaf area and gas exchange of banana plants. The use of the Bacillus sp. promoted a reduction in Na + levels in plant tissues.