The effects of Antarctic water-soluble humic acid on the growth of Arabidopsis thaliana and Lactuca sativa

초록

Humic acids (HA) is a well-known plant growth enhancer. Antarctic tundra soil exhibits unique properties due to its distinct environmental conditions and vegetation. In this region, HA is primarily derived from grasses, mosses, and lichens, which contributes to the lower lignin content of Antarctic HA compared to that of HA from other regions. Therefore, the biostimulant potential of Antarctic soil-derived HA is likely to differ. In this study, we comparatively analyzed the structural characteristics of Antarctic water-soluble fraction of HA (KS-WSHA) and commercial water-soluble HA (SiA-WSHA), and evaluated their effects on plant growth promotion in Arabidopsis thaliana and Lactuca sativa. Structural analysis revealed that KS-WSHA exhibits higher molecular weight and nitrogen content, and a lower aromaticity than SiA-WSHA. Despite the presence of similar functional groups, such as -OH and -COOH, more amine groups were detected in KS-WSHA than in SiA-WSHA. Both WSHAs promoted A. thaliana growth in vitro at 1 and 10 mg<middle dot>L-1, enhancing fresh weight, dry weight, and root length. In hydroponic systems, all concentrations (10-1000 mg<middle dot>L-1) of KS-WSHA improved shoot biomass, root length, and leaf development in L. sativa, whereas only at 1000 mg<middle dot>L-1 SiA-WSHA positively influenced L. sativa growth. These findings highlight the potential of KS-WSHA as a biostimulant for promoting plant growth.

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