Root and shoot development of corn seedlings as affected by rhizobacteria.

Multifunctional microorganisms are beneficial microorganisms able of promoting plant growth through direct and indirect mechanisms. Because of this, has enormous potential for use when aiming a sustainable agriculture. The objective of this work was to determine the effect of seed inoculation with multifunctional microorganisms on the initial development of corn seedlings. The experiment was carried out under controlled conditions in a completely randomized design, with seven treatments and six replications. Treatments consisted of microbiolization of corn seeds with the rhizobacteria: 1. Burkholderia cepacea (BRM 32111), 2. Serratia marcenses (BRM 32113), 3. Serratia sp. (BRM 32114), 4. Bacillus sp. (BRM 63573), 5. Azospirillum brasilense (Ab-V5), 6. Azospirillum sp. (BRM 63574) and 7. control treatment (no microorganisms). For each experimental unit, 500 mL plastic pots filled with soil and two corn seeds were used. After 14 days the seedlings were removed from the pots, set aside from the ground and photographed with a digital camera. The images presented were analyzed by WinRHIZO 2012 software to determine: total root length, root diameter, total root surface area and root volume. After this, roots and shoots of the seedlings were dried and weighed. Corn seedlings treated with the multifunctional microorganisms Bacillus sp. (BRM 63573), Serratia sp. (BRM32114) and Azospirillum sp. (BRM 63574) presented increased in the root and shoots biomass compared to untreated seeds. The microorganism Azospirillum sp. (BRM 63574) was the one that provided the highest values in the parameters of total root length, root diameter, root volume, root dry mass, shoot dry mass and total dry mass compared to the control treatment. The use of multifunctional microorganisms is a promising alternative to provide greater development of corn seedlings.