Bacillus megaterium Compensates for Growth Inhibition from Phosphorus Deficiency by Improving Photosynthetic Capacity, Changing Antioxidant Potential, and Regulating Non-Structural Carbohydrate Concentrations in Glycyrrhiza uralensis

This study assessed the effect of Bacillus megaterium on seedling growth of Glycyrrhiza uralensis Fisch. under control and phosphorus (P) deficiency conditions. The results showed that P deficiency improved 1) G. uralensis root growth, 2) superoxide dismutase, catalase, and peroxidase activities, 3) inorganic P, starch, and soluble sugar contents in roots, 4) dissipated energy flux per reaction center, trapped energy flux per reaction center, and absorption flux per reaction center, and 5) net photosynthetic rate, stomatal conductance, transpiration rate, maximum fluorescence intensity after dark adaptation, and variable fluorescence. However, P deficiency significantly decreased chlorophyll and carotenoid contents in G. uralensis, but enhanced chlorophyll and carotenoid contents in B. megaterium. Our findings on the regulatory mechanisms of B. megaterium in response to P starvation hold promise for improving the success of G. uralensis cultivation. Keywords: Bacillus megaterium; Glycyrrhiza uralensis Fisch; Phosphorus deficiency; Chlorophyll fluorescence; Antioxidant enzymes superoxide; Non-structural carbohydrate