Evaluation of drought resistance of ten wild ornamental grass germplasm during seed germination stage

Ten wild ornamental grasses were subjected to osmotic stress of approximately 0 to -1.3 MPa created with polyethyleneglycol (PEG-6000). As the osmotic stress decreased, the germination rare, germination potential, germination index, plumule length, and radicle length first increased and then decreased, however, fresh weight of seedling gradually decreased; in addition to Pennisetum alopecuroide (Ningxian), Pennisetum alopecuroide(Lingtai), and Eragrostis ferruginea(Lingtai), the vigor index of other germplasm gradually decreased. Osmotic stress at -0.1 MPa promoted germination of seeds of all the ten wild ornamental grasses, their germination rate, germination potential, germination index, plumule and radicle length reached the maximum values at this osmotic stress level, and the initial germination days of Achnatherum splendens(Lanzhou), Achnatherum splendens(Wuwei), Eragrostis ferruginea(Lingtai), Deschampsia cespitosa(Tianzhu) were one day shorter than the control. Beyond -0.5 MPa,the germination of these ten wild ornamental grass seeds was severely suppressed. Furthermore, beyond -1.3 MPa, seeds of all these varieties did not germinate at all. Using the subordinate function analysis to evaluate drought resistance, the varieties were ranked as follows: Achnatherum splendens (Lanzhou)>Pennisetum alopecuroide (Ningxian)>Achnatherum splendens (Wuwei)>Pennisetum alopecuroide (Lingtai)>Achnatherum splendens (Sunan)>Carex rochebrunii (Weiyuan)>Deschampsia cespitosa(Weiyuan)>Deschampsia cespitosa (Tianzhu)>Carex nubigena (Weiyuan)>Eragrostis ferruginea (Lingtai).