Abstract:

【Objective】The objective of this experiment is to determine the main Na+ exclusion localization of buckwheat (Fagopyrum esculentum Moench) and the correlation between proton pump and Na+/H+ antiport activity with Na+ exclusion property. 【Method】Buckwheat varieties Chuanqiao 1 (salt-tolerant variety) and TQ-0808 (salt-sensitive variety) were used as experimental materials. Na+ exclusion capability of different parts was determined through “pressure chamber” method extruding xylem juice. Proton pump and Na+/H+ antiport activity were also determined by sucrose density gradient centrifugation method separating plasmolemma and tonoplast. 【Result】The main Na+ exclusion localization of salt-sensitive variety was in roots, while that of salt-tolerant one was in roots and stem base, and the whole Na+ exclusion capability of salt-tolerant variety was obviously higher than that of salt-sensitive one. Proton pump and Na+/H+ antiport activity of salt-tolerant variety were obviously higher than that of salt-sensitive one in the same salinity treatment. It indicated that Na+ extrusion capability and Na+ circumscription capability of the main Na+ exclusion localization cell in salt-tolerant variety were obviously higher than that in salt-sensitive one. 【Conclusion】Na+ circumscription of the main Na+ exclusion localization in salt-tolerant variety played an important role in restricting transportation Na+ to shoot, which was the main way to Na+ exclusion of main Na+ exclusion localization in salt-tolerant buckwheat variety.

Key words: buckwheat, NaCl, Na+ exclusion capability, Na+ exclusion localization, Na+/H+ antiport activity