The Role of Plasma Membrane and Na + / H + Transporters in Wheat Roots in Salt Resistance

Cytoplasmic Na + / K + ratio is very important in the process of plant salt resistance. Sweet soil plants (such as wheat) can prevent excessive cytoplasmic Na + / K + ratio by increasing Na + efflux at the root. Na + efflux is an energy-consuming process. The Na + / H + transporter on the plasma membrane is considered to be an active efflux system that can transport Na + out of plant cells. Although this active efflux system is of great significance in salt tolerance, at present, little is known about the quantitative evaluation of its activity and the relationship between activity and salt tolerance, and there is a lack of Na + / H + transporter activity for any plant variety. A quick and convenient method for quantitative evaluation.

In March 2011, Australian researchers studied the sodium ion flow and internal sodium ion concentration in the roots of different varieties of wheat through non-damage micro-measurement technology (MIFE), laser confocal, and scanning electron microscopy. The study found that the active sodium efflux of wheat root cells is regulated by the SOS1 gene family and is powered by the plasma membrane proton pump. The salt-tolerant wheat variety Kharchia 65 had the highest efflux activity, and the laser confocal results showed that Kharchia 65 could separate more Na + into the vacuole. These results are consistent with the higher expression levels of SOS1 (Na + / H + transporter on plasma membrane) and NHX1 (Na + / H + transporter on vacuole membrane) in this variety. In salt-sensitive varieties of wheat, a large amount of Na + is localized in the root cell cytoplasm, which destroys the cell's Na + / K + balance.

The above results indicate the relationship between Na + distribution and salt tolerance in wheat, illustrate the important role of cytoplasmic Na + efflux in wheat salt tolerance, and propose a quantitative measure of the transporter ’s ability to contribute to salt tolerance Convenient method.