Abstract

Salicylic acid (SA) belonging to plant phenolics group is found in some plant species and is capable of enhancing plant growth and yield. Effects of SA application (10⁻³ and 10⁻⁵ M) on synthesis of total soluble carbohydrate (TSC), total flavonoids (TF) and total phenolics (TP) were studied out in two ginger varieties (Halia Bentong and Halia Bara) under greenhouse conditions. In treated plants as the level of SA increased (from 10⁻⁵M to 10⁻³M) the production of TF increased while synthesis of TP decreased. SA induced production of TSC content in both varieties. Halia Bara exhibited a higher content of TSC (7.98 mg/g dry weight) compared to Halia Bentong (7.59 mg/g dry weight) when sprayed with low concentration (10⁻⁵M) of SA. The result of high performance liquid chromatography (HPLC) analysis showed that concentration of the some majority flavonoids (quercetin, catechin and kaempferol) decreased significantly in plants when treated with different concentration of SA. Accordingly, high concentrations of these flavonoids were found in control plants. Furthermore, SA application stimulated synthesis of phenolic acids (cinnamic acid, vanillic acid, ferulic acid and gallic acid) in both varieties. These increases might be due to an increase in TSC content. The results implied that SA could be used for improving biochemical synthesis in young ginger.

Key words: Salicylic acid, ginger, total soluble carbohydrate, total phenolics,