Membrane-Potential Alteration During K+ Uptake of Different Salt-Tolerant Wheat Varieties

K+ is the most abundant cation in plant cells and plays an important role in many ways. K+ uptake of plant has respect to its salt resistant capacity. There are two categories of channel transportation for plants to uptake K+, one is through K+ channels and the other is through nonselective cation channels (NSCCs). The transmembrane localization of K+ may change membrane potential (MP). In this paper, three wheat varieties with different salt tolerance were selected and the MP was measured by microelectrode during K+ uptake. The results showed that the effects of K+ uptake on MP through K+ channels or NSCCs were distinct. K+ influx through K+ channels led to MP hyperpolarization, while K+ influx through NSCCs resulted in depolarization. Diverse MP alteration of wheat varieties with different salt tolerance was mainly due to NSCCs-mediated K+ uptake. Compared with the salt-tolerant wheat, the MP hyperpolarization during K+ uptake of salt-sensitive wheat was much more evident, probably because of the cation outflux through NSCCs during this process.