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    郎涛, 李妮亚, 鲁彦君, 孙会敏, 申泽丹, 荆晓姝, 赵瑞, 沈昕, 陈少良. 胞外ATP、H2O2 、Ca2+ 与NO 调控木榄根系离子平衡机理研究[J]. 北京林业大学学报, 2014, 36(4): 16-22. DOI: DOI:10.13332/j.cnki.jbfu.2014.04.007
    引用本文: 郎涛, 李妮亚, 鲁彦君, 孙会敏, 申泽丹, 荆晓姝, 赵瑞, 沈昕, 陈少良. 胞外ATP、H2O2 、Ca2+ 与NO 调控木榄根系离子平衡机理研究[J]. 北京林业大学学报, 2014, 36(4): 16-22. DOI: DOI:10.13332/j.cnki.jbfu.2014.04.007
    LANG Tao, LI Ni-ya, LU Yan-jun, SUN Hui-min, SHEN Ze-dan, JING Xiao-shu, ZHAO Rui, SHEN Xin, CHEN Shao-liang. Extracellular ATP, hydrogen peroxide, calcium and nitric oxide mediate root ion fluxes in Bruguiera gymnorrhiza subjected to salt stress[J]. Journal of Beijing Forestry University, 2014, 36(4): 16-22. DOI: DOI:10.13332/j.cnki.jbfu.2014.04.007
    Citation: LANG Tao, LI Ni-ya, LU Yan-jun, SUN Hui-min, SHEN Ze-dan, JING Xiao-shu, ZHAO Rui, SHEN Xin, CHEN Shao-liang. Extracellular ATP, hydrogen peroxide, calcium and nitric oxide mediate root ion fluxes in Bruguiera gymnorrhiza subjected to salt stress[J]. Journal of Beijing Forestry University, 2014, 36(4): 16-22. DOI: DOI:10.13332/j.cnki.jbfu.2014.04.007

    胞外ATP、H2O2 、Ca2+ 与NO 调控木榄根系离子平衡机理研究

    Extracellular ATP, hydrogen peroxide, calcium and nitric oxide mediate root ion fluxes in Bruguiera gymnorrhiza subjected to salt stress

    • 摘要: 运用非损伤微测技术(NMT),研究了短期盐胁迫下胞外ATP(eATP)、H2 O2 、Ca2 + 与NO 对非泌盐红树木榄根 系K+/Na+ 平衡的调控作用。NaCl(100 mmol/L,24 h)与等渗甘露醇处理的实验表明,木榄根尖对盐胁迫的响应具 有高度的离子特异性。盐胁迫增强了木榄根尖的Na+ 外流,但Na+ 外流被Na+ /H+ 逆向转运蛋白抑制剂Amiloride 和质膜H+ -ATPase 抑制剂Vanadate 抑制,表明Na+ 外流源于根尖表皮细胞质膜Na+ /H+ 逆向转运系统驱动的Na+ 外排。短期盐胁迫处理能诱导木榄根尖K+ 外流,但被氯化四乙胺(TEA,外向K+ 通道抑制剂)明显抑制,证明K+ 外流是由激活的去极化外向型离子通道KORCs 介导。胞外ATP(300 mol/L)、H2 O2 (10 mmol/L)、Ca2 + (10 mmol/ L)与SNP(NO 供体,100 mol/L)均能增加短期盐胁迫下的Na+ 外流,同时抑制K+ 外流。其中,促进Na+ 外流效果 较强的是H2 O2 和Ca2 + ,而Ca2 + 和NO 抑制K+ 外流的效果突出。这些实验结果表明,胞外ATP、H2 O2 、Ca2 + 与NO 这4 种盐胁迫信使是通过上调木榄根系细胞质膜Na+ /H+ 逆向转运体系(Na+ /H+ 逆向转运体和H+ 泵)活性,在促 进Na+ 和H+ 逆向跨膜转运的同时,抑制去极化激活的K+ 离子通道来减少盐诱导的K+ 外流。

       

      Abstract: Using the non-invasive micro-test technique (NMT), the effects of extracellular ATP (eATP), hydrogen peroxide (H2O2), calcium (Ca2 + ) and nitric oxide (NO) on root K+ /Na+ homeostasis were investigated in a non-secretor mangrove species Bruguiera gymnorrhiza under short-term (ST, 24 hours) salt stress (100 mmol/L NaCl). The experiments of NaCl and Mannitol in B. gymnorrhiza roots indicated that there were mainly high ion-specific effects on NaCl-induced ion fluxes in roots. Salt stress resulted in an increased Na+ efflux along the root axis of B. gymnorrhiza. However, the salt-enhanced Na+ efflux was inhibited by amiloride, a Na+ /H+ antiporter inhibitor or sodium orthovanadate, a plasma membrane (PM) H+ -ATPase inhibitor obviously, suggesting that the Na+ efflux was resulted from active Na+ exclusion. NaCl treatment caused an evident K+ efflux in B. gymnorrhiza, but it was significantly restricted by the K+ channel blocker, TEA, suggesting that the K+ efflux was mediated by K+ permeable channels. Exogenously applied eATP (300 mol/L), H2O2 (10 mmol/L), Ca2 + (10 mmol/L), or SNP (NO donor, 100 mol/L) enhanced the salt-elicited Na+ efflux but reduced K+ efflux under ST treatment. Under salt stress, H2O2 and Ca2 + showed a high capacity to exclude Na+ , while the inhibition of K+ efflux was more pronounced by Ca2 + or NO application. In conclusion, our data revealed that eATP, H2O2, Ca2 + , and NO upward regulated Na+ /H+ antiporter and H+ pump, an activity of Na+ / H+ antiport system, which compelled the Na+ /H+ exchange across the plasma membrane and restricted the K+ loss via depolarization-activated K+ channels simultaneously.

       

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