Original Articles
Debasis Mitra*, Komal Sharma,
Abstract
Plant hormones (Indole-3-Acetic Acid) regulate and influence the developmental range of cellular and physiological process of plant health. In the present study, ten PGPA bacteria were isolated from rhizospheric soil of Asparagus racemosus(L). Morphological and biochemical test showed that the isolates named KNAD1, KNAD2, KNAD6, KNAD9, KNAD10 belong to genus Bacillus. These isolates were further screened for PGPA like Phosphate Solubilization, production of ammonia and cell wall degrading enzymes. KNAD2, KNAD4, KNAD5, KNAD7, KNAD9 & KNAD10 showed high potential in Phosphate Solubilization and others PGPA. In this study,indole-3- acetic acid (IAA) production by these isolates were carried out day wises and then results showed that on Day2: KNAD6 (86.72ppm); Day3: KNAD7 (85.63ppm); Day4: KNAD2 (116.83ppm); Day5: KNAD4 (121.54ppm); Day6: KNAD1 (86.17ppm); Day7: KNAD6 (126.60ppm) of IAA (μg ml-1) were produced in the presence of tryptophan (1 mg ml-1) at optimum conditions of 37°C and 0.5% NaCl. Additionally, it was further observed that at 1%, 2%and 7% tryptone concentration in the nutrient broth the bacterial growth increased. These results suggest that production of IAA in presence of tryptone might be promising factor for the implementation in plant growth and development.