Abstract: By the method of solution culture, this paper studied the effects of different concentrations exogenous nitric oxide (NO) donor (sodium nitroprusside, SNP) on the seed germination and seedling growth of ryegrass (Lolioum multiflorum). The results showed that 50 and 100 μmol SNP·L^-1 increased the seed germination rate, seedling’s dry matter accumulation, germinated seed α-amylase activity, and leaf soluble protein and chlorophyll contents. The reduced glutathione (GSH) and ascorbic acid (ASC) contents and the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities in seedling’s roots and leaves also increased, but the generation of O₂^-_·and the accumulation of malondialdehyde (MDA) and H₂O₂ decreased. High concentration SNP (500-2000 μmol SNP·L^-1) inhibited the seed germination and seedling growth of L. multiflorum. The contents of soluble protein, chlorophyll, GSH and ASC as well as the activities of SOD, POD and APX decreased, but the MDA content, production rates of H₂O₂ and O₂^-_·, and CAT activity increased. It was suggested that NO could promote the seed germination and seedling growth of L. multiflorum through increasing its seed amylase activity and seedling’s scavenging ability of reactive oxygen species.

Key words: Ginger, Meloidogyne incognita, Inoculation density, Yield