Open Access

ARTICLE

Moderate CO₂ Enrichment Enhances Saponin Accumulation in Panax japonicus by Activating Sugar Metabolism

Xiao Wang^*, E Liang, Xiaohui Song, Deyan Li

College of Agriculture, Anshun University, Anshun, China

* Corresponding Author: Xiao Wang. Email:

(This article belongs to the Special Issue: Plant Responses and Adaptations to Environmental Stresses)

Phyton-International Journal of Experimental Botany 2026, 95(3), 20 https://doi.org/10.32604/phyton.2026.075656

Received 05 November 2025; Accepted 29 December 2025; Issue published 31 March 2026

Abstract

Three-year-old Panax japonicus was exposed to elevated CO₂ concentrations using open-top chambers: ambient CO₂ (aCO₂), moderately elevated (e1CO₂, 550 μmol/mol), and highly elevated (e2CO₂, 750 μmol/mol). Gas exchange parameters, photosynthetic pigments, sugar accumulation, and total saponin content were measured to assess the effects of CO₂ enrichment on photosynthesis, sugar metabolism, and saponin biosynthesis. The e1CO₂ treatment significantly increased net photosynthetic rate (by 17.22% at 36 days and 69.62% at 92 days), chlorophyll a content, and soluble sugar, sucrose, and starch accumulation. Key sugar metabolism enzymes, including sucrose phosphate synthase (SPS), also showed enhanced activity. Consequently, underground rhizome total saponins rose significantly by 15.16%. In contrast, e2CO₂ initially (36 days) stimulated photosynthesis but lost this effect over prolonged exposure (92 days), with no significant impact on photosynthetic parameters, pigments, or sugar levels. Correlation analysis indicated that rhizome saponin content was positively associated with leaf sucrose levels and sucrose synthase (synthetic direction) activity. These findings suggest that moderate CO₂ elevation (e1CO₂) enhances P. japonicus photosynthesis and sugar metabolism, driving greater saponin accumulation. However, high CO₂ (e2CO₂) has transient benefits, with stimulatory effects diminishing over time.

---

Keywords

---