Abstract:

[Objective] This study aimed to explore the effects of exogenous nitrogen priming on seed germination characteristics of Bothriochloa ischaemum. [Method] The Bothriochloa ischaemum seeds were used as experimental materials. After priming with different concentrations （0, 70, 140, 280, 560, 1 120 mmol/L） of NH₄NO₃ solution for 0 （CK）, 3, 6, 9, and 12 h, respectively, the changes in seed germination rate, germination index, mean germination time, and seedling vigor index were analyzed to reveal the responses of Bothriochloa ischaemum seed germination to exogenous nitrogen priming. [Result] Nitrogen concentration, priming time and their interaction had extremely significant （P<0.01） effects on the seed germination rate, germination index, mean germination time, and seedling vigor index of Bothriochloa ischaemum. The seed germination rate, germination index, and seedling vigor index of Bothriochloa ischaemum showed an upward trend when the concentrations of NH₄NO₃ solution ranged from 0 to 140 mmol/L, and exhibited a downward trend when the concentrations of NH₄NO₃ solution ranged from 280 to 1 120 mmol/L, while the change trend of mean germination time was the opposite. [Conclusion] The seed germination ability of Bothriochloa ischaemum was improved with the lower concentrations （≤140 mmol/L） of NH₄NO₃ solution priming, and was inhibited with the higher concentrations （≥280 mmol/L） of NH₄NO₃ solution priming. The optimal treatment for Bothriochloa ischaemum seeds was priming with NH₄NO₃ solution at concentration of 140 mmol/L for 6 h in production practice.

Key words: Bothriochloa ischaemum, seed germination, nitrogen deposition, nitrogen priming, seed vigor