Na+ localization and re-transportation of buckwheat seedlings

Salt-tolerant buckwheat (Fagopyrum esculentum Moench) variety Chuanqiao No. 1 and salt-sensitive buckwheat variety TQ-0808 were used as experimental materials. Na+ content of roots, stem base and leaves were determined to find out the localization and re-transportation traits of buckwheat under NaCl stress and removing NaCl stress. It showed that Na+ accumulation of roots and stem base of salt-tolerant buckwheat variety was obviously more than that of the salt-sensitive one, which could efficiently restrict Na+ from transporting to shoot, and made salt-tolerant buckwheat variety has less Na+ content of leaves and more salt tolerance. Na+ accumulation capability of stem base was obviously higher than that of roots of the two buckwheat varieties; it showed that stem base was a very important Na+ exclusion localization of buckwheat. Na+ re-transportation capability of leaves of salt-tolerant buckwheat variety was obviously higher than that of the salt-sensitive one after removing NaCl stress, which had more correlation with higher Na+ re-transportation capability of salt-tolerant buckwheat variety. In addition, the net photosynthetic rate of salt-tolerant buckwheat variety had not obviously changed in contrast with control under NaCl stress; however, that of salt-sensitive buckwheat variety significantly decreased, and it was still significantly lower than the control after removing NaCl stress. These findings showed that the part of roots and stem base of buckwheat might be the main Na+ exclusion localization.