Growth promotion and protection from drought in Eucalyptus grandis seedlings inoculated with beneficial bacteria embedded in a superabsorbent polymer

CHAIN, J. M.; TUBERT, E.; GRACIANO, C.; CASTAGNO, L. N.; RECCHI, M; PIECKENSTAIN, F.; ESTRELLA, M. J.; GUDESBLAT, G.; AMODEO, G.; BAROLI, I

Scientific Reports

Springer

Año: 2020

Eucalyptus grandis is a globally important tree crop. Greenhouse-grown tree seedlings often facewater deficit after outplanting to the field, which can affect their survival and establishment severely.This can be alleviated by the application of superabsorbent hydrophilic polymers (SAPs). Growthpromoting bacteria can also improve crop abiotic stress tolerance; however, their use in trees islimited, partly due to difficulties in the application and viability loss. In this work, we evaluated theimprovement of drought tolerance of E. grandis seedlings by inoculating with two Pseudomonasstrains (named M25 and N33), carried by an acrylic-hydrocellulosic SAP. We observed significantbacterial survival in the seedling rhizosphere 50 days after inoculation. Under gradual water deficitconditions, we observed a considerable increase in the water content and wall elasticity of M25-inoculated plants and a trend towards growth promotion with both bacteria. Under rapid water deficitconditions, which caused partial defoliation, both strains significantly enhanced the formation of newleaves, while inoculation with M25 reduced the transpiration rate. Co-inoculation with M25 and N33substantially increased growth and photosynthetic capacity. We conclude that the selected bacteriacan benefit E. grandis early growth and can be easily inoculated at transplant by using an acrylichydrocellulosic SAP.