Abstract: Leafy vegetables are rich in nutrients such as vitamins and dietary fiber, which are essential to people’s daily diet. Microbial inoculants play an important role in promoting plant growth and nutritional qualities. In this study, two combined microbial inoculants of Arthrobacter pascens BUAYN-122 and Bacillus subtilis BUABN-01 were applied in the hydroponic system for lettuce (Lactuca sativa L.) and celery (Apium graveolens L.) cultivation. After harvesting, the agronomic characters, physicochemical properties and nutritional qualities of lettuce and celery were determined. The paper aimed to evaluate the application of the combined microbial inoculants on hydroponic cultivation of lettuce and celery. The results showed that the microbial inoculants significantly improved the aboveground fresh weight, underground fresh weight, root length, leaf length and leaf number of both lettuce and celery. The root dehydrogenase activity, net photosynthetic rate, stomatal conductance and total chlorophyll content of thetwo vegetables were significantly improved, indicating that the microbial inoculation can promote the root nutrient uptake and leaf photosynthesis. Furthermore, the microbial inoculants could significantly increase the total protein, vitamin C and total phenol contents of lettuce and celery, anthocyanin and total flavonoid contents of lettuce, and soluble sugar and total dietary fiber contents of celery. The results of this study confirmed that the application of microbial inoculants in hydroponics systems can promote the yield and the quality of lettuce and celery.
Keywords: Lactuca sativa L. , Apium graveolens L. , Arthrobacter pascens , Bacillus subtilis, Vitamin C
