PGPR inoculation improves growth, nutrient uptake and physiological parameters of Capsicum chinense plants

The Habanero pepper (Capsicum chinense) is intensivelycultivated in the Yucatan peninsula, Mexico. Because of adverseenvironmental conditions, it required seeding in germinationtrays, from which six-week-old seedlings were transplanted to thesoil. Adequate nursing and fertilization programmes were made toimprove health and vigour before seedlings transplanting. Duringseed germination, we investigated the effects of inoculation withfour plant growth-promoting rhizobacteria (PGPR) on growth,nutrient uptake and gas exchange of 8-week-old Capsicum chinenseplants. Inoculation was made with Pseudomonas sp. -P61-, Pseudomonassp. -A46-, Bacillus pumillus -R44-, and Paenibacillus polymyxa-BSP1.1-. The BSP1.1 strain produced the highest increase in plantheight (22.52 cm), leaf area (99 cm2), fresh weight of roots (0.337g) and shoots (2.83 g), and dry weights of roots (0.05 g) and shoots(0.43 g). Nitrogen uptake was similar (P>0.05) among treatments.However, seedlings inoculated with BSP1.1 had a higher accumulationthan controls when they were exposed to P and K (50 and40%, respectively). Likewise, seedlings inoculated with the BSP1.1strain improved both photosynthesis (2 μmol/m2/s) and water useefficiency (7.3 μmol CO2/mmol H2O), and decreased transpirationrate (0.27 mmol/m2/s). Thus, the inoculation with the BSP1.1 strainwas the best option to enhance growth and vigour of Capsicum chinenseplants.