Rhizobacteria-Vitamin-Plant Synergism Interaction and its Biostimulant Properties on Gas Exchange and Growth of Sorghum Plants Subjected to Water Deficit

Changes in climatic conditions in agricultural environments have significantly altered how we produce food.The introduction of more resilient species and technologies that enhance their productive potential has been continually studied.In this context, sorghum is a promising crop for cultivating areas less favorable for corn.When combined with growthpromoting and bioprotective bioinputs, it can support the establishment of the crop and mitigate the effects of adverse environmental conditions.This study evaluated the effect of applying Azospirillum brasilense and nicotinamide on the gas exchange and growth characteristics of sorghum plants under water deficit stress.The experiment was conducted in a greenhouse using a randomized block design with four treatments and five replications.The treatments were: T1 (control), T2 (foliar application of nicotinamide at 200mg L -1 ), T3 (foliar application of A. brasilense at 2mL L -1 ), and T4 (combined application of nicotinamide and A. brasilense).It was found that the application of both products, either together or separately, increased the gas exchange capacity of the plants after water stress, along with a gain in root volume ranging from 86% to 127%, which was accompanied by increased dry weight accumulation in both the shoot and the root system.We conclude that foliar application of A. brasilense and nicotinamide, alone or in combination, promotes improvements in gas exchange and growth in sorghum plants subjected to water stress, particularly in the root organs.