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

ESTEBAN TUBERT; CASTAGNO; GUDESBLAT, GUSTAVO; BAROLI IRENE; CORINA GRACIANO; F PIECKENSTAIN; AMODEO, GABRIELA; CHAIN, JOSE-MARÍA; MARINA RECCHI; MJ ESTRELLA

Congreso; Plant Biology - ASPB 2021 Worldwide Summit; 2021

ASPB

Eucalyptus grandisis a globally planted tree crop. Improvements in this species managementcan have a considerable economic impact, but it is also necessary to develop managementpractices that are environmentally friendly and sustainable. Greenhouse-grown tree seedlingsoften face water deficit after outplanting to the field, which can affect their survival andestablishment severely. This can be alleviated by the application of superabsorbent hydrophilicpolymers (SAPs). Growth-promoting bacteria can also improve crop abiotic stress tolerance;however, their use in trees is limited, partly due to difficulties in the application and viability loss.In this work, we evaluated the improvement of the drought tolerance ofE. grandisseedlings afterinoculating with twoPseudomonasstrains (named M25 and N33), carried by an acrylic-hydrocellulosic SAP. We observed significant bacterial survival in the seedling rhizosphere 50days after inoculation. Under gradual water deficit conditions, we observed a considerableincrease in the water content and wall elasticity of M25-inoculated plants and a trend towardsgrowth promotion with both bacterial strains. Under rapid water deficit conditions, which causedpartial defoliation, both strains significantly enhanced the formation of new leaves, whileinoculation with M25 reduced the transpiration rate. Co-inoculation with M25 and N33substantially increased growth and photosynthetic capacity. We conclude that the selectedbacteria can benefit the early growth ofE. grandisand can be easily inoculated at transplant byusing an acrylic-hydrocellulosic SAP