Gas exchange and leaf area of banana plants under salt stress inoculated with growth-promoting bacteria¹

Trocas gasosas e área foliar de bananeiras sob estresse salino inoculadas com bactérias promotoras de crescimento

HIGHLIGHTS:

Banana cv. Prata Catarina has its gas exchange negatively affected by irrigation water salinity.

Bacillus sp. did not reduce the harmful effect of salinity on the gas exchange and leaf area of banana.

Salinity influences the leaf area similarly to photosynthesis.

ABSTRACT

Banana orchards in arid and semiarid regions require the use of irrigation. However, the presence of high concentration of salts in water can impair the development of plants, requiring the evaluation of new technologies to mitigate the effects of stress. The objective of this study was to evaluate gas exchange and leaf area in banana seedlings of the cultivar Prata Catarina inoculated with strains of Bacillus spp. under different electrical conductivities of irrigation water. The experiment was carried out in a greenhouse at Embrapa Tropical Agroindustry, Fortaleza, Ceará state, Brazil. The design used was in randomized blocks, in a 4 × 4 factorial scheme, with the first factor being the inoculation treatments: without any application; slow-release fertilizer; Strain 186 and Strain 109, and the second factor being the electrical conductivity of irrigation water (0.5; 1.5; 3.0; 4.5 dS m^-1), in five blocks and each plot consisting of three plants. The electrical conductivity of irrigation water negatively influenced the gas exchange of banana cv. Prata Catarina in the vegetative stage, during the 89 days of cultivation. The Bacillus spp. strains 186 and 109 did not improve the gas exchange and leaf area of plants under salinity conditions.

Key words:
Bacillus sp.; photosynthetic limitations; growth; salinity