低盐胁迫对坛紫菜（Pyropia haitanensis）离子转运的影响

从离子实时动态转运的角度出发，分析坛紫菜应答低盐胁迫的策略。研究结果表明:1）坛紫菜在正常状态下吸收K+、Na+以维持自身稳态；在低盐胁迫下，坛紫菜藻体的Na+显著外排，以积极应对外界低渗环境，同时，藻体的K+虽然有一定流失，但显著低于高盐胁迫条件下的K+外排幅度，使坛紫菜能够维持较高的K+/Na+，从而保证坛紫菜可以适应盐度5的环境条件。2）加入Na+/H+逆向转运蛋白抑制剂阿米洛利后，并不能显著抑制坛紫菜藻体Na+的外排，表明低盐胁迫下藻体并不是通过质膜质子泵驱动Na+/H+逆向转运蛋白将Na+排出藻体，可能通过非选择性阳离子通道外排Na+至细胞外。3）加入质膜质子泵抑制剂钒酸钠后，藻体K+的流速并没有受钒酸钠影响，初步说明低盐胁迫下坛紫菜K+的流失并不是通过去极化激活的外向通道来完成。这从离子动态的角度证明了低盐胁迫下坛紫菜排钠保钾的方式和应答高盐胁迫时存在明显区别。

Effects of Low Salt Stress on Ion Transport in Pyropia haitanensis

From the perspective of real time dynamic transport of ions,this paper analyzed the strategy of P.haitanensis in response to low salt stress.The results showed that thallus absorbed K + and Na+ to maintain its own homeostasis under normal condition.However,under the low salt stress,the Na + of the thallus was significantly effluxed to actively respond to the external hypotonic environment.At the same time,although there was some loss of K + in the thallus,it was significantly lower than the K + efflux range under high salt stress,so that P.haitanensis could maintain a higher K +/Na+,thus ensuring that P.haitanensis could adapt to salinity 5.However,the addition of the Na +/H+ antiporter inhibitor amiloride did not significantly inhibit the Na + efflux of thallus,indicating that under low salt stress,thallus does not drive Na+/H+ antiporter through the plasma membrane proton pump to expel Na + out of the thallus,but may expel Na + to the outside of the cell through nonselective cation channels.At the same time,the flow rate of K + in the thallus was not affected by the plasma membrane proton pump inhibitor sodium vanadate,which indicated that the loss of K+ in thallus under low salt stress was not accomplished by depolarizing activated outward channels.Therefore,from the perspective of ion dynamics,this study proved that there was a significant difference between the way of removing sodium and retaining potassium from P.haitanensis under low salt stress and responding to high salt stress.