ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Plant Physiology
Exogenous GABA Regulates the Growth Traits, Photosynthesis, Antioxidant Properties, and Nitrogen Metabolism in Isatis indigotica Fortune Seedlings
Provisionally accepted
- 1Yili Normal University, Yili, China
- 2Key Laboratory of Plant Resources Protection and Utilization in Xinjiang Yili Valley, Yili Normal University, Yining, China
- 3Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan, China
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To investigate the effects of exogenous γ-aminobutyric acid (GABA) application on the growth, development, and related parameters associated with different physiological and biochemical processes of Isatis indigotica Fortune (I. indigotica) seedlings, a pot experiment was conducted. Seedlings were collected from two provenance areas (Gansu and Hebei) and treated at the six-leaf stage with four GABA concentrations: 0 (CK), 2.5 (T1), 5 (T2), and 7.5 (T3) mM·L-1. Compared with CK, T1 and T2 treatments improved plant height, total fresh mass, and total dry mass at all sampling stages, with increments of 0.99%-7.86%, 2.99%-12.79%, and 1.27%-6.90%, respectively. These promotional effects were attributed to increased photosynthetic capacity, pigment contents, and activities of nitrogen metabolism enzymes. Meanwhile, root morphology was also promoted by T1 and T2 treatments. In contrast, inhibitory effects of T3 treatment on plant height, total biomass accumulation, and root morphology were also observed. Furthermore, exogenous treatments T1 and T2 markedly elevated the antioxidant capacity of I. indigotica seedlings, as evidenced by the increased activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), along with the enhanced soluble protein content in both leaves and roots. Meanwhile, these two treatments significantly reduced the accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the aboveground and underground tissues of the seedlings. Structural equation modeling (SEM) further revealed that the total antioxidant capacity exerted positive regulatory effects on plant height, total biomass accumulation, and root morphological traits through both direct and indirect pathways. Principal component analysis (PCA) demonstrated that T2 treatment induced the most prominent variation in seedling growth and physiological traits. Specifically, glutamate synthase (GOGAT) activity showed the strongest correlation with the first principal component (PC1), while POD activity was most closely associated with the second principal component (PC2). Collectively, these findings suggest that 5 mM·L-1 is the optimal concentration of exogenous GABA for the cultivation of I. indigotica seedlings.
Keywords: Growth and Development, Isatis indigotica Fortune, Physiological and biochemical parameters, seedlings, γ-Aminobutyric acid
Received: 19 Nov 2025; Accepted: 27 Jan 2026.
Copyright: © 2026 Ren, Cheng, Fan, He, Mei, Liu and Sun. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yong Ren
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