Effects of Drought Stress on Drought Resistance of Three Species of Stipa Seeds During Germination

Three species of Stipa seeds(S.bungeana,S.grandis and S.sareptana var.krylovii) in Ningxia Hui Autonomous Region were taken as a test materials,the effects of drought stress on their germination were studied under different gradients of polyethylene glycol(PEG-6000).Results showed that as the drought intensified,seed germination rate,vitality index,seedling fresh weight and drought resistance index of the three species declined.Especially,the declinations for S.grandis were most significant(p0.05).The low concentration of PEG(5% PEG) had a certain improvement to seed germination and seedling growth of S.bungeana.Compared with the control treatment,the low concentration of PEG did not significantly reduce the seed germination rate and seedling fresh weight of S.sareptana var.krylovii,which indicates that S.sareptana var.krylovii has a certain drought resistant potential.PEG had a greater inhibiting effect on the seedling growth than that on the root.The drought resistances of the three species declined in the order of S.bungeanaS.sareptana var.kryloviiS.grandis.