Effects of rhizobacteria on seed germination of water spinach (Ipomoea aquatica)

Rhizobacteria are considered as the most useful microorganism based on their properties in nitrogen fixing, phosphate and potassium solubilizing, IAA and other plant  hormones which improve the germination of seed. However, seed germination varied depending on stimulator such as bacterial strains, bacterial growing media. This  investigation focused on testing the germination of Ipomoea aquatica vegetable by using three rhizobacteria isolates including H1-702, C1-112, P1-5071 and their growing media. Percentage of seed germination, shoot length, root length and number of root hairs of  I. aquatica were lowest found in nutrient media treatments without bacteria (50%, 1.67 cm, 1.47 cm, and 1.47, respectively) while the highest numbers were obtained from the treatment of soaked seed with bacterial suspension which gave rise 90%, 4.88 cm, 3.01 cm and 19.26, respectively. Among all treatments, percentage of seed germination was highest (83%) in the single inoculums treatments C1-112 and H1-702. In day 5, the highest root length (2.4 cm) and root hair number (22.05) was showed in H1-702 treatment while C1-112 treatment revealed the highest shoot length (4.52 cm). The combination of  two bacterial isolates did not stimulate the germination of I. aquatica , especially, P-H treatment which got the lowest number in all observation data.