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

CHAIN JM; TUBERT E; GRACIANO C; CASTAGNO LN; RECCHI M; PIECKENSTAIN FL; ESTRELLA MJ; GUDESBLAT G; AMODEO G; BAROLI I

SCIENTIFIC REPORTS

Nature Publishing

Año: 2020

Eucalyptus grandisis acommercially important tree crop worldwide. Greenhouse-grown tree seedlings often face water deficit afteroutplanting to the field, which can affect their survival and establishment severely. This can be alleviatedby the application of superabsorbent hydrophilic polymers (SAPs). Growth promoting bacteria can alsoimprove crop abiotic stress tolerance; however,their use in trees is limited, partly due to difficulties in the applicationand viability loss. In thiswork, we evaluated the improvement of drought tolerance of E. grandis seedlings by inoculating with two Pseudomonas strains (named M25 and N33), carried by anacrylic hydrocellulosic SAP. We observed significant bacterial survival in theseedling rhizosphere 50 days afterinoculation. Under gradual water deficit conditions, we observed a considerable increase in the water content and wallelasticity of M25-inoculated plants and a trend towards growth promotion with both bacteria. Under rapid waterdeficit conditions, which caused partial defoliation, both strains significantly enhanced theformation of new leaves, while inoculation with M25 reduced the transpiration rate.Co-inoculation with M25 and N33 substantially increased growth andphotosynthetic capacity. We conclude that the selected bacteria can benefit E. grandis early growth and can be easily inoculated attransplant by using an acrylic hydrocellulosic SAP.