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Acta Prataculturae Sinica ›› 2025, Vol. 34 ›› Issue (3): 164-174.DOI: 10.11686/cyxb2024177

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Physiological and biochemical responses of Bothriochloa ischaemum seedlings to salt stress at seedling stage and definition of salt tolerance threshold

Shou-yu GAO(), Wen-jing LIU, Yu-ying LI(), Qing-yuan XIANG, Jia-jun XU, Lei-qi SHU, Zhao-zhong LI   

  1. College of Grassland Science,Shanxi Agricultural University,Jinzhong 030801,China
  • Received:2024-05-14 Revised:2024-06-20 Online:2025-03-20 Published:2025-01-02
  • Contact: Yu-ying LI

Abstract:

Soil salinization is one of the important limiting factors restricting the development of the pastoral industry in northern China. Developing local grass germplasm resources with strong saline-alkali resistance is an effective means to overcome difficulties utilizing saline-alkali land. This study investigated the salt-tolerance mechanisms and salt-tolerance threshold of Bothriochloa ischaemum cv. ‘Taihang’ seedlings. Nine NaCl salt stress treatments were set up, and plant height, root length, aboveground biomass and other 13 other plant traits were measured. Salt-tolerance threshold was calculated by principal component analysis. The results showed that NaCl stress had a greater influence on the growth of the shoots of B. ischaemum seedlings, but the root system was more sensitive to Na+ and K+. With increase in both stress exposure time and NaCl concentration, the activities of peroxidase and superoxide dismutase in leaves initially increased and then decreased, and reached their maxima on the 8th and 10th day, respectively, in a treatment of 210 mmol·L-1 NaCl. The contents of malondialdehyde and soluble sugar showed an upward trend over time, while chlorophyll content showed a downward trend. After principal component analysis (PCA), the first two sets of PC scores (root length and dry weight) were selected to establish regression relationship. From this evaluation it was found that the dry weight of aboveground parts was the most suitable criterion for evaluating salt tolerance, and the salt tolerance threshold of B. ischaemum seedlings was approximately 207.53 mmol·L-1. This study provides preliminary insight about the salt tolerance mechanism of grasses and for planning of subsequent research on the impact of exposure duration and salt concentration on salt tolerance in B. ischaemum.

Key words: Bothriochloa ischaemum, salt tolerance threshold, physiological and biochemical changes, principal component analysis