植物生态学报 ›› 2017, Vol. 41 ›› Issue (4): 489-496.doi: 10.17521/cjpe.2016.0091

• • 上一篇    

沙枣幼苗根尖离子流对NaCl胁迫的响应

杨升1,2,*, 张华新2, 陈秋夏1, 杨秀艳2   

  1. 1 浙江省亚热带作物研究所, 浙江温州 325005
    2 国家林业局盐碱地研究中心, 北京 100091
  • 收稿日期:2016-03-09 接受日期:2016-09-21 出版日期:2017-04-10 发布日期:2017-05-19
  • 通讯作者: 杨升
  • 基金资助:
    国家“十二五”科技支撑计划(2011BAD38B0102)和中央公益科研院所基本科研业务费专项资金(CAFYBB2012009)

Responses of apical ion fluxes to NaCl stress in Elaeagnus angustifolia seedlings

Sheng YANG1,2,*, Hua-Xin ZHANG2, Qiu-Xia CHEN1, Xiu-Yan YANG2   

  1. 1 Zhejiang Institute of Subtropical Crops, Wenzhou, Zhejiang 325005, China
    and
    2Research Center of Saline and Alkali Land of State Forestry Administration, Beijing 100091, China
  • Received:2016-03-09 Accepted:2016-09-21 Online:2017-04-10 Published:2017-05-19
  • Contact: Sheng YANG

摘要:

为了进一步从离子动态运输方面了解沙枣(Elaeagnus angustifolia)耐盐机制和揭示沙枣种源间的K+/Na+平衡调控差异, 该研究利用非损伤微测技术(non-invasive micro-test technology, NMT)测定银川种源(盐敏感型)和阿拉尔种源(耐盐型)沙枣幼苗根系在3种不同NaCl处理方式下的离子流: 1)在150 mmol·L-1 NaCl胁迫24 h后的Na+和K+离子流; 2) NaCl瞬时处理后的K+和H+的动态离子流; 3)先NaCl胁迫24 h, 再用Na+/H+逆向转运体抑制剂阿米洛利(Amiloride)和K+通道抑制剂氯化四乙胺(TEA)处理后的Na+和K+离子流。结果表明: NaCl胁迫24 h后, 沙枣根系Na+和K+外排净流量显著增加, 并且银川种源沙枣幼苗根系Na+净流量显著低于阿拉尔种源, 净流量分别为720和912 pmol·cm-2·s-1, 而K+外流净流量显著高于阿拉尔种源。瞬时NaCl处理后, 沙枣根系K+的外流迅速增加, 并且银川种源的K+外排净流量始终高于阿拉尔种源, 而H+由内流转为外排, 阿拉尔种源的H+净外流量大于银川种源。NaCl和NaCl + Amiloride处理下, 阿拉尔种源沙枣幼苗Na+外流的净流量均大于银川种源, 但K+外流的净流量均小于银川种源, 而在对照和NaCl + TEA处理下, Na+和K+的净流量在两个种源间无明显差异。研究证明NaCl胁迫造成根系Na+积累和K+外流, 沙枣幼苗为减少Na+积累, 通过根系Na+/H+逆向转运体将Na+从体内排出, 并且耐盐型种源沙枣幼苗根系在NaCl胁迫时能更好地维持体内的K+/Na+平衡, 其原因主要在于具有较强的Na+外排能力和较弱的K+流失。该研究可以为进一步发掘优良耐盐沙枣种质资源提供理论参考依据。

关键词: 沙枣, NaCl胁迫, 离子流, 种源, Na+/H+逆向转运体, K+/Na+平衡

Abstract:
Aims Elaeagnus angustifolia is one of the most salt-tolerant species. The objective of this study was to understand the mechanisms of ion transporation in E. angustifolia exposed to different salt concentrations through manipulations of K+/Na+ homeostasis.
Methods Seedlings of two variants of the species, Yinchuan provenance (YC, salt-sensitive type) and the Alaer provenance (ALE, salt-tolerant type), were treated with three different NaCl application modes, and the ion fluxes in the apical regions were measured using non-invasive micro-test technology (NMT). In mode 1, Na+ and K+ fluxes were measured after 150 mmol·L-1 NaCl stress lasted for 24 h. In mode 2, K+ and H+ fluxes were quantified with a transient stimulation of NaCl solution. In mode 3, Amiloride (Na+/H+ antiporters inhibitor) and tetraethylammonium (TEA, K+ channel inhibitor) was used to treat apical regions of E. angustifolia seedlings after NaCl stress for 24 h, respectively.
Important findings Under NaCl stress for 24 h, net effluxes of Na+ and K+ were increased significantly. The net Na+ effluxes of YC provenance seedlings (720 pmol·cm-2•s-1) were lower than that of ALE provenance (912 pmol·cm-2·s-1), but the net K+ efflux was higher in YC provenance. Under the instantaneous NaCl stimulation, net K+ efflux was remarkably increased, with the net K+ efflux of YC provenance always higher than that of ALE provenance. Interestingly, H+ at the apical regions was found from influx to efflux, with the net H+ efflux of ALE provenance greater than that of the YC provenance. Under the NaCl and NaCl + Amiloride treatment, the net Na+ efflux of ALE provenance seedlings was higher than that of YC provenance, while the net K+ efflux was less in ALE provenance seedlings. On the other hand, the differences in net Na+ and K+ effluxes were insignificant between the two provenances under the control group and NaCl + TEA treatment. In conclusion, NaCl stress caused Na+ accumulation and K+ outflows of E. angustifolia seedlings; The E. angustifolia seedlings utilize Na+/H+ antiporters to reduce Na+ accumulation by excretion; and the maintenance of K+/Na+ homeostasis in salt-tolerant E. angustifolia provenance seedlings roots accounted for a greater Na+ extrusion and a lower K+ efflux under NaCl stress. Results from this study provide a theoretical basis for further exploring salt-tolerant E. angustifolia germplasm resource.

Key words: Elaeagnus angustifolia, NaCl stress, ion fluxes, provenance, Na+/H+ antiporters, K+/Na+ homeostasis