沙枣幼苗根尖离子流对NaCl胁迫的响应  

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

作　　者：杨升[1,2] 张华新[2] 陈秋夏[1] 杨秀艳[2] 

机构地区：[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

出　　处：《植物生态学报》2017年第4期489-496,共8页Chinese Journal of Plant Ecology

基　　金：国家"十二五"科技支撑计划(2011BAD38B0102);中央公益科研院所基本科研业务费专项资金(CAFYBB2012009)

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。Aims Elaeagnus angustifolia is one of the most salt-tolerant species. The objective of this study was to under- stand 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 quanti- fied with a transient stimulation of NaCl solution. In mode 3, Amiloride （Na^＋/H^＋ antiporters inhibitor） and tetra- ethylammonium （TEA, K^＋ channel inhibitor） was used to treat apical regions of E. angustifolia seedlings after NaCI stress for 24 h, respectively. Important findings Under NaCl stress for 24 h, net effiuxes of Na^＋ and K^＋ were increased significantly. The net Na^＋ effiuxes of YC provenance seedlings （720 pmol＇cm-2.s-1） were lower than that of ALE provenance （912 pmol＇cm-2. s-l）, but the net K^＋ effiux was higher in YC provenance. Under the instantaneous NaCl stimulation, net K^＋ effiux was remarkably increased, with the net K^＋ effiux of YC provenance always higher than that of ALE provenance. Interestingly, H^＋ at the apical regions was found from influx to effiux, with the net H^＋ effiux of ALE provenance greater than that of the YC provenance. Under the NaCl and NaCl^＋ Amiloride treatment, the net Na^＋ effiux of ALE provenance seedlings was higher than that of YC provenance, while the net K^＋ effiux 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 ca

关 键 词：沙枣 NACL胁迫 离子流 种源 Na+/H+逆向转运体 K^+/Na^+平衡 

分 类 号：S793.9[农业科学—林木遗传育种]