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Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (3): 200-211.DOI: 10.11686/cyxb2022083

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Comprehensive screening of Agropyron cultivars for tolerance to salt stress at the seedling stage

Han MIAO1,2(), Lai WEI1,2, Yan-ping YANG1,2, Yong-he CHE1,2()   

  1. 1.Hebei Key Laboratory of Crop Stress Biology,Qinhuangdao 066000,China
    2.College of Agronomy and Biotechnology,Hebei Normal University of Science and Technology,Qinhuangdao 066000,China
  • Received:2022-02-19 Revised:2022-04-25 Online:2023-03-20 Published:2022-12-30
  • Contact: Yong-he CHE

Abstract:

Agropyron is a perennial grass in the Triticeae (Poaceae). It has the advantages of resistance to drought, cold, and salinity, so it is an excellent crop for saline-alkali land improvement. To provide a basis for the evaluation of salt tolerance of Agropyron, seedlings of two main Agropyron cultivars, Agropyron mongolicum cv. Mengnong No.1 and Agropyron cristatum×Agropyron desertorum cv. Hycrest-Mengnong, were exposed to salinity stress using five concentrations of seawater in a pot experiment in a greenhouse. Thirty days later, twelve indexes were investigated including root length (RL), shoot height, superoxide dismutase (SOD) activity, malondialdehyde content,and K+ content. The effects of salt stress on the seedling growth characteristics, K+/Na+, antioxidant enzyme activity, and contents of osmotic regulatory substances in the Agropyron materials were analyzed. The saline tolerance coefficient of each index under different seawater treatments was calculated, and then the salt tolerance of Agropyron at the seedling stage was comprehensively analyzed by a principal components analysis, subordinate function analysis, and regression analysis. All of the indexes except for the relative water content of the shoot showed significant differences (P<0.05) among the different salt stress treatments. A principal components analysis was conducted using ten indexes to evaluate the salt tolerance of the Agropyron at the seedling stage. A regression analysis identified three important factors in salt stress tolerance: An osmotic adjustment factor, a plant type factor, and a root system factor. The following mathematical evaluation model for Agropyron salt tolerance was established by regression analysis: D=0.833-0.018SOD-0.147SP-0.042SS-0.142Pro-0.004Na+-0.520 K+-0.076RL, where SP=soluble protein, SS=soluble sugars and Pro=proline. Using this equation, the salt tolerance of Agropyron germplasm resources could be quickly and accurately predicted on the basis of seven indexes: SOD, K+, Na+, SP, SS, Pro, and RL. These analyses revealed that the salt tolerance of Hycrest-Mengnong was higher than that of Mengnong No.1. The results of this study will be useful for promoting and managing the cultivation of grasses in salinized areas.

Key words: Agropyron, seedling stage, salt tolerance, index screening