Abstract: At different soil saline contents, the effect of inoculation with different vesicular-arbuscular mycorrhizal (VAM) fungal isolates on saline-tolerance of cotton, corn, soybean and melon plants were investigated with pot experiment. The results show that the infection rate of fungi to the four plants and the biomass of them were declined with increasing NaCl level in soil, while the dependency of these plants on VAM fungi were enhanced. At a given NaCl level, cotton, maize and soybean plants inoculated with VAM fungi had a higher biomass than that of non-mycorrhizal plants. With application of 0～3g·kg^-1 NaCl, the dry weight of cotton inoculated with M₁ isolate was increased by 4.6～80.9%; with application of 0～2.5g·kg^-1 NaCl,the dry weight of maize inoculated with M₁ isolate was increased by 20.0～109.6%; and with application of 1g·kg^-1 NaCl, the dry weights of soybean inoculated with M₁ and M₂ isolates were increased by 22.1% and 10.2%, respectively. Different fungal isolates had different effects on saline-tolerance of same plants, and same isolate had different effects on saline-tolerance of different plants. It is suggested that the VAM fungi-plant symbiosis might play an important role on plant survival on saline soil, and that inoculation with VAM fungi could enhance plant production on saline soil and reduce the loss of plant yield causing by salt.

Key words: Vesicular-arbuscular mycorrhizal fungi, Saline-tolerance of plant, NaCl stress, Bio-improvement of saline soil