Chinese Bulletin of Botany ›› 2026, Vol. 61 ›› Issue (3): 437-448.DOI: 10.11983/CBB25046  cstr: 32102.14.CBB25046

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Effect of Salt Stress on Carbohydrate Secretion by the Root System of Thinopyrum ponticum

Congcong Yi1,2,3, Dan Li1,2,3, Yanjie Li1,2,3, Xiuwen Lin1,2,3, Yingshuai Lu1,2,3, Xiaopeng Chen1,2,3,*()   

  1. 1 College of Grassland Science, Shanxi Agricultural University , Taigu 030801, China
    2 Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation , Taigu 030801, China
    3 Youyu Loess Plateau Grassland Ecosystem National Research Station , Youyu 037200, China
  • Received:2025-03-24 Accepted:2025-09-02 Online:2026-05-10 Published:2025-09-05
  • Contact: Xiaopeng Chen

Abstract: INTRODUCTION: The carbohydrates secreted by plant roots play a crucial role in modulating the carbon source supply and metabolic activity of soil microorganisms. RATIONALE: In order to unveil the response mechanism of root-secreted carbohydrates in salt-tolerant plants to the intensity of salt stress, this study focused on the salt-tolerant forage grass Thinopyrum ponticum. Four levels of salt stress intensity were conducted by adding NaCl, including control, light, moderate, and heavy stress conditions (with soil salt contents of 0%, 0.2%, 0.4%, and 0.6%, respectively). Untargeted metabolomics techniques were employed to analyze the compositional alterations of root-secreted carbohydrates and their correlations with the rhizosphere soil properties were evaluated. RESULTS: The results demonstrated that: (1) Compared to the control, salt stress significantly decreased the contents of five types of carbohydrates, namely glycoside, aminoglycoside, D-glucosamine, 2-O-methyl-L-fucose and galactoside, while markedly increasing glucose content; (2) Glycosides were the predominant carbohydrates secreted by T. ponticum roots, accounting for (79.63±8.19)% of the total relative abundance, whereas the remaining five carbohydrate types ranged from (3.40±0.53)% to (4.57±1.61)%; (3) Root-secreted carbohydrates exhibited significant differences between the control and light, moderate, or heavy salt stress treatments, but no significant distinctions were observed among the latter three treatments; (4) Soil electrical conductivity and nitrate nitrogen content were identified as key factors responsible for the down-regulation of the five carbohydrate types, while soil pH was the primary factor driving the up-regulation of glucose. CONCLUSION: T. ponticum can adapt to salt-stressed environments by regulating the content of carbohydrates secreted by its roots. Meanwhile, the abundance of carbohydrates secreted by the roots is also influenced by the soil properties.

Key words: salinization, root exudates, Thinopyrum ponticum, carbohydrates