Study on gibberellin and gibberellin-like substances from endophytes and their effect on maize plants

Plant growth promoting endophytes were isolated from the roots of rice, sugarcane, corn, maize, sunflower and chili. The biochemical characterization of those isolated endophytes was carried out according to Bergey's Manual of Determinative Bacteriology. The best gibberellin production of all isolates was found at the concentration of (55.12 ppm, 50 ppm, 38.06 ppm, 90.41 ppm, 58.65 ppm and 63.65 ppm, respectively) on the 12th day of the incubation period. Among all isolates, the A4 isolate produced more GA concentration (90.41 ppm) on the 12th day of the incubation period. In the maize seed germination test, A1, A4, A5 and A6 showed the best results. In the pot trial test, A4, A5 and A6 showed the best results in shoot length (37.5 cm, 35.4 cm and 36.9 cm per ten replicates, respectively). Among them, the A4 isolate was the best GA producing isolate for plant growth promoting activity in maize seedlings. It was found in an average shoot height of 37.5 cm; average shoot fresh weight of 56.7 g and an average shoot dry weight of 7.9 g per ten replicates after one month cultivation which was sprayed by A4 treatment, compared with an average shoot height of 27.80 g, an average shoot fresh weight of 25.08 g, an average shoot dry weight of 3.42 g which were sprayed by water treatment. The qualitative analysis of plant growth regulators (GAs) production of bacterial isolate A4 was determined by using TLC method and FTIR spectroscopy analysis. Chemical fertilizers should not be used not to harm effective endophytes.