Revegetation in landslide-affected areas is challenging due to the extensive terrain and poor soil quality. Applying bacteria with plant growth-promoting (PGP) traits offers a promising approach to support plant growth in these disturbed regions. This study aimed to investigate seed enhancement methods by selecting bacterial strains and developing seed pellet mixtures to facilitate revegetation processes. Specifically, we focused on enhancing the germination rate and growth of Acacia confusa through seed pretreatment and inoculation with native bacteria in the growing substrate for pot cultivation and seed pellets. Fifty-four native bacterial strains were isolated from the rhizosphere and endo-rhizosphere of A. confusa growing in the Dadu plateau, Taiwan. Isolates were tested for their ability to stimulate or inhibit the growth of A. confusa seeds on Petri dishes. Sixteen isolates with germination parameters significantly differing from the control were selected for pot tests. 16S rDNA gene sequencing showed that most strains belonged to the genus Bacillus and exhibited one or more PGP traits. Seedling growth parameters were significantly improved by inoculating the substrate with isolates A2TP3 (Bacillus proteolyticus) and A2SP5 (Lysinibacillus sphaericus), which exhibited strong abilities to enhance shoot growth and were therefore selected for evaluation in seed pellet production. Seed germination after inoculation in seed pellets varied with the mixture used. This study demonstrated that bacterial inoculation is a promising bio-inoculant for A. confusa on specific substrates; however, further experiments on seed pelleting mixtures are still needed.
Nxumalo et al. (Sun,) studied this question.