Azospirillum brasilense affects survival, growth and nutrient status of micropropagated sugarcane (Saccharum spp.) plantlets during ex vitro conditions

Azospirillum brasilense is a rhizobacterium that promotes growth and has physiological effects on the development of different crops. This study evaluated the effect of different doses of A. brasilense on the survival, growth and nutrient status of micropropagated sugarcane (Saccharum spp.) cv. Mex 69–290 plantlets during ex vitro conditions. Sugarcane plantlets were inoculated with control, 0.5, 1, 1.5, and 2 × 106 CFU (Colony-Forming Units) per ml of A. brasilense during acclimatization. After 60 days of greenhouse acclimatization, we evaluated the survival percentage, plantlet development, dry matter percentage, chlorophyll content, β-carotene content, and macro and micronutrient content. Results indicate that the inoculation of Saccharum spp. with A. brasilense had dose-dependent effects on the evaluated physiological and development-related variables. The 1 × 106 CFU/ml dose of A. brasilense maintained a high survival rate, provided adequate growth and favored N, P, Mg, Mn, and B absorption. However, the 2 × 106 CFU/ml dose of A. brasilense had negative effects on survival and development. The symbiotic interaction between A. brasilense and Saccharum spp. during acclimatization represents an alternative to improve plantlet quality before field transplantation. Future research is required on the effect of A. brasilense during the commercial establishment of basic sugarcane seedbeds.