Salt Tolerance on Seed Germination of Five Leymus Species

To determine the effect of salt stress on seed germination of Leymus species, seeds of Leymus racemosus (Lam.) Tzvel., Leymus angustus (Trin.) Pilger, Leymus multicaulis (Kar. et Kir.) Tzvel., Leymus duthiei (Stapf) Y. H. Zhou et H. Q. Zhang and Leymus secalinus (Georgi) Tzvel. were treated with NaCl solutions of different concentration: 0 mmol/L, 100 mmol/L, 200 mmol/L, 300 mmol/L, 400 mmol/L and 500 mmol/L and the germination rate, germination index, time of seeds beginning to germinate, the growth of radicle and plumule were observed. The results showed that (1) the germination percentage and germination index of the five species of Leymus were declined with increasing salinity; (2) the times for seeds to germinate and complete germination were prolonged under high salinity stress; (3) the growth of radicle and plumule has been descended with the intensifying of the salt concentration; (4) plumule was more sensitive to salt stress than radical; (5) salt-tolerant ability of L. duthiei was the highest among the five Leymus species, while that of L. angustus was the lowest; (6) the tolerance of L. multicaulis surpassed that of L. secalinus and L. racemosus.