Enhancement of antioxidant activity and biomass by mineral water in rehmannia root (Rehmannia glutinosa L. purpurea Makino)

摘要

We investigated the functional mechanisms of brine mineral water (BMW) in plants. Antioxidant activities were determined by DPPH free radical-scavenging analysis of crude extracts of Rehmannia glutinosa treated with BMW. The DPPH was measured by value for the density of antioxidant required to absorbance equal to 50% that of a control containing no antioxidant. Plants treated with 0.05-0.1% BMW showed weak antioxidant activity. The concentrations of the principal mineral components, Mg2+, K+, and Sr2+ were increased in samples treated with 1% BMW. Antimicrobial activities of BMW-treated R. glutinosa were determined. The greatest inhibition was against Salmonella typhimurium and Klebsiella pneumoniae. The effect of BMW treatment on plant growth over four weeks was investigated and determined by addition of distilled water into 100% BMW, which plant growth was enhanced about 8 cm by 0.05-0.1% BMW. The expression of marker genes involved in plant metabolism was monitored in control and BMW- treated plants. The RgAPX gene was induced in 5% BMW-treated plants after 48 h, and transcription of the PAL gene was significantly higher in 5% BMW–treated plants after both 1 and 48 h. In addition, rbcL gene expression was higher in BMW-treated than in control plants. These data suggest that BMW has various effects in plants. This work explains the relationship between biological activity and biomass in terms of the expression of functional genes. BMW affects biological activities, growth, and the secondary metabolism of plants.