Exploring the influence of differential diurnal temperatures on <i>Panax ginseng</i> sprouts: implications for morpho-physiology, antioxidants, minerals, and ginsenosides content

Abstract

Panax ginseng C.A. Meyer, a valuable medicinal plant with abundant antioxidants has been used for centuries due to its potential health benefits including boosting of immune system, cognitive function, sexual function and reducing stress. The popularity of ginseng sprouts (GS) is driven by their convenience and ease of use as a ginseng consumption option, particularly when compared to mature ginseng roots. Employing controlled environmental conditions, including the adjustment of artificial lighting and air temperature, presents an appealing approach for cultivating GS of high quality within a condensed timeframe. In this study, we investigated the impact of four distinct day-night temperature difference (DIF) regimes, viz., - 4 DIF (18/22 degrees C), 0 DIF (20/20 degrees C), 0 DIF (22/22 degrees C), and + 4 DIF (22/18 degrees C), on the morpho-physiology, antioxidant activity, and the accumulation of minerals and ginsenosides in GS. To promote growth parameters, both positive and zero DIF conditions (22/22 degrees C) were beneficial, however the positive DIF condition played a significant role in enhancing chlorophyll a levels, photosynthetic efficiency, and enzymatic antioxidant activities. Although negative DIF was conducive for mineral accumulation, it had adverse effects on growth, antioxidant activities, and ginsenoside production. The zero DIF, particularly (22/22 degrees C) has boosted the non-enzymatic antioxidant activities and mineral uptake, while (20/20 degrees C) has facilitated the ginsenoside synthesis. The significant upregulation of ginsenoside biosynthesis genes further validated the accumulation of ginsenosides under zero DIF conditions. Hence, the present study elucidates the advantageous implications of diverse DIF conditions, offering a potential avenue for enhancing ginseng cultivation in the vertical farming system.