Promoção de crescimento por bactérias Endofíticas em mudas de Musa spp

Abstract

Seedlings multiplied by micropropagation are free of bacteria and other contaminants. Plant growth-promoting endophytic bacteria play an important role in cultivation and can be found in the root, leaf and pseudostem of the banana tree.The association of different species of endophytic bacteria with the rhizosphere of host plants can stimulate growth, development and acclimatization, offering more seedlings, and anticipating the cycle, providing economic return. Thus, it is necessary to study the reintroduction of these bacteria into the root system of Musa spp. The objective of this work was to evaluate the efficacy of growth promoting endophytic bacteria in the acclimatization of micropropagated banana seedlings. For this, the following treatments were tested: T0- Control (nutrient agar); T1- Bacterium F01; T2- Bacterium R21; T3- Bacterium F12 and T4- Bacterium 11.1. During the acclimatization period, we evaluated morphoagronomic variables related to seedling development, such as: total height and pseudostem diameter (mm). After 90 days of transplantation (DAT) and acclimatization, pseudostem length (mm) and root length (cm), number of leaves, dry / fresh root mass, pseudostem, leaf (g) and leaf area were evaluated. The physiological variables evaluated were: stomatal conductance (GS) mol H2O m-2 s-1; photosynthesis rate (A) “μmol CO2 m-2 s-1”; perspiration rate (E) "mmol H2O m-2 s-1"; leaf temperature (Tº) and SPAD. The bacteria presented different results in relation to the cultivars studied. Taking into account the biometric, morphological and physiological variables, it is recommended for the acclimatization process of banana seedlings to use the bacterium R21 for the cultivars Prata Anã and Grande Naine and absence of bacteria for the BRS Princesa for stimulating plant growth, increasing fresh and dry mass, promoting root growth and improving the physiological aspects of the plant.