The antioxidant content and activity of lemongrass [Cymbopogon citratus (DC. ex Nees) Stapf] under the combination of drought stress and nano-silica treatments

Abstract: The study aimed to determine the effect of a combination of drought stress and nano-silica treatments to increase the content of antioxidant compounds and antioxidant activity of lemongrass [Cymbopogon citratus (DC. ex Nees) Stapf] and determine the optimal combination. The research used a Completely Randomized Design (CRD) with two factors with 5 replications. The first factor was the level of drought stress (without drought stress, moderate, and severe). The second factor was the nano-silica dose, (0 mg/L, 125 mg/L, and 250 mg/L) with a volume of 10 mL per plant. The parameters measured were carotenoid content, proline content, total phenolics content, and antioxidant activity. Data were analyzed using Analysis of Variance (ANOVA) and Duncan’s Multiple Range Test (DMRT). The results showed that there is a specific combination of drought stress and nano-silica which can increase the content of carotenoids, proline, total phenolics, and antioxidant activity in lemongrass. The treatment of moderate and severe drought stress with 125 and 250 mg/L nano-silica increased the carotenoid and proline content maximally. Higher total phenol content and antioxidant activity were obtained from the combination of 250 mg/L nano-silica without drought stress. The highest chlorophyll content was recorded from the combination of severe drought stress and 250 mg/L nano-silica. Drought stress treatment with 250 mg/L nano-silica could increase the antioxidants of lemongrass plants, but maximum production of antioxidants required different combinations of drought stress and nano-silica treatments. Nano-silica treatment at a dose of 250 mg/L in conditions of sufficient water or lack of water can be an optimal combination treatment in lemongrass cultivation.