Under salt stress, recretohalophyte Plumbago auriculata tetraploids enhance salt tolerance by increasing selective secretion of Na+ compared with that in diploids, although the mechanism is unclear. Using non-invasive micro-test technology, the effect of salt gland Ca2+ content on Na+ and K+ secretion were investigated in diploid and tetraploid P. auriculata under salt stress. Salt gland Ca2+ content and secretion rates of Na+ and K+ were higher in tetraploids than in diploids under salt stress. Addition of exogenous Ca2+ increased the Ca2+ content of the salt gland in diploids and is accompanied by an increase in the rate of Na+ and K+ secretion. With addition of a Ca2+ channel inhibitor, diploid salt glands retained large amounts of Ca2+, leading to higher Ca2+ content and Na+ secretion rate than those of tetraploids. Inhibiting H2O2 generation and H+-ATPase activity altered Na+ and K+ secretion rates in diploids and tetraploids under salt stress, indicating involvement in regulating Na+ and K+ secretion. Our results indicate that the increased Na+ secretion rate of salt gland in tetraploids under salt stress was associated with elevated Ca2+ content in salt gland.

中文翻译：

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盐胁迫下盐腺中Ca2+积累的增加增加了白花白花四倍体选择性分泌Na+的能力

盐胁迫下，泌盐植物Plumbago auriculata四倍体通过增加Na的选择性分泌来增强耐盐性+与二倍体相比，尽管机制尚不清楚。采用非侵入式微测试技术，盐腺Ca的效果2+Na含量+和K+研究了盐胁迫下二倍体和四倍体 P. auriculata 的分泌情况。盐腺钙2+Na含量及分泌率+和K+盐胁迫下四倍体的含量高于二倍体。添加外源Ca2+增加了钙2+二倍体盐腺含量增加，并伴随着 Na 比率的增加+和K+分泌。添加 Ca2+通道抑制剂，二倍体盐腺保留大量Ca2+，导致较高的 Ca2+含量和Na+分泌率高于四倍体。抑制H2氧2一代和H+-ATP酶活性改变Na+和K+盐胁迫下二倍体和四倍体的分泌率，表明参与调节Na+和K+分泌。我们的结果表明，增加的Na+盐胁迫下四倍体盐腺分泌率与Ca升高相关2+盐腺中的含量。