Study on germination characteristics of four forage seeds under different stresses

In order to explore the stress resistance of forage seeds during the germination period, in this study, NaCl and polyethylene glycol (PEG-6000) were used to simulate salt and drought stress, respectively, on the germination of four test species, Astragalus adsurgens, Artemisia desertorum, Melilotus officinalis, and Medicago falcata The stress resistance indexes were relative germination rate, relative germination potential, relative germination index, and relative vigor index. The results showed that: 1) with increased NaCl concentration, all indexes of seeds showed a downward trend. The membership function method was used to comprehensively evaluate the salt tolerance of the tested species at the germination stage; the order of salt tolerance was: M. falcata > A. desertorum > M. officinalis > A. adsurgen. 2) Low-concentration PEG (5%) stress treatment significantly promoted the seed germination index of three forage grasses, A. adsurgen, A. desertorum, and M. falcata, compared with the control group. Each index under 10%～20% PEG was significantly lower than that of the control group (P < 0.05). The membership function method was used to analyze the drought resistance of the four forage species at the germination stage. The comprehensive ranking was as follows: M. falcata > M. officinalis > A. desertorum > A. adsurgen. This indicated that the seeds of M. falcata had the strongest drought resistance and salt tolerance at the germination stage.