Effects of ethephon on physiological characteristics and gene expression of Tartary buckwheat under salt stress

Salt-tolerant ‘Chuanqiao No.1’ and salt-sensitive ‘Chuanqiao No.2’ Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) were used as materials. Effects of ethephon on physiological characteristics of Tartary buckwheat under salt stress were studied by different concentrations of ethephon (ETH) under 150 mM NaCl stress. Ethephon treatment could improve seed germination rate of both varieties under salt stress, and the effect of ethephon treatment on salt-sensitive variety was better. Ethephon treatment could improve physiological characteristics of Tartary buckwheat seedlings under salt stress, and appropriate concentrations of ETH root treatment in salt-tolerant and salt-sensitive variety were 1.0 and 1.5 mM, and for ETH spraying were 0.4 and 0.6 mM. The effect of ETH spraying on improving physiological characteristics of Tartary buckwheat under salt stress was better than that of ETH root treatment. Salt tolerance gene FtNHX1 reached its maximum expression level at 24 h, which was increased by 277.77% and 251.17% in salt-tolerant and salt-sensitive variety compared with salt stress under ETH root treatment, while under ETH spraying treatment, which was increased by 232.39% and 190.91% in salt-tolerant and salt-sensitive variety compared with salt stress. Salt tolerance gene FtSOS1 reached its maximum expression levels at 12 h, which was increased by 60.94% and 98.75% in salt-tolerant and saltsensitive variety compared with salt stress under ETH root treatment, while under ETH spraying treatment, which was increased by 35.98% and 67.63% in salt-tolerant and salt-sensitive variety compared with salt stress. Key word: Ethephon, physiological characteristics, salt stress, Tartary buckwheat.