Endophytic bacteria in seed germination and rooting of Pinus spp.

Abstract

The inoculation of seeds with associative and growth-promoting bacteria is a prosperous mechanism to achieve high germinability rates and production of well-developed plants, in addition to the aspects related to the rhizogenic process in the clonal propagation of superior genotypes. Consequently, the objective of this work was to isolate endophytic bacteria from Pinus caribaea var. hondurensis plant tissues and evaluate its potential as a promoter in seed germination and rooting of P. taeda mini-cuttings. Hence, endophytic bacteria were isolated from Pinus caribaea var. hondurensis micro-plants grown in vitro and phenotypically characterized. From this collection of formed endophytic isolates, in addition to two Azospirillum brasilense commercial strains, seed germination and rooting tests of Pinus taeda L. mini-cuttings were established. Bacterial inoculation promoted the germination rate, germination speed and vigor of the seedlings. A. brasilense and CNPF 316 promoted an increase in the percentage of rooted mini-cuttings, number and average length of roots. The isolates present characteristics of plant growth-promoting bacteria, as they enhance the development of plant physiological and morphological stages.