Evaluation of germination response and the resistance of main plant species seedling to drought stress in the hill-gullied Loess Plateau region of northern Shaanxi

In the hill-gullied Loess Plateau region of northern Shaanxi, lack of soil water is a dominant factor affecting vegetation restoration, and the effect of drought stress on seed germination is a key limiting factor for plant regeneration. This experiment was conducted to estimate the seed germination characteristics and drought resistance of 16 main plant species in the hill-gullied Loess Plateau region. Different concentrations of polyethylene glycol (PEG-6000) solution were used to simulate the drought stress in this study. The results showed that germination of all seeds was subjected to different degrees of inhibition with the increase of PEG concentration. Generally, with drought stress increase, the seed germination time lag was prolonged, or even the seeds did not germinate, and the germination potential, germination rate, germination index, and drought resistance index of all seeds tended to decline. However, slight drought stress (50 g·L-1) promoted the germination of some seeds and increased seed germination potential and germination rate. The comprehensive evaluation of the relative germination potential, relative germination rate, relative germination index, and drought resistance index of 16 species by the membership function method indicated that the drought resistance of Bidens pilosa, Artemisia scoparia, and Setaria viridis was the strongest, and that of Stipa grandis was the weakest.