《植物生理学报》 2013, 49(1): 34-40

不同耐盐性小麦根Na⁺和K⁺的吸收特性

丁同楼, 贾玉辉, 鲍敬, 王宝山*

山东师范大学生命科学学院, 逆境植物重点实验室, 济南250014

通信作者：王宝山；E-mail: bswang@sdnu.edu.cn；Tel: 0531-86180197

摘　要：

以耐盐小麦品种‘德抗961’和盐敏感小麦品种‘鲁麦15’为材料, 研究小麦根Na+、K+吸收特性及其与耐盐性关系。结果表明, 2个小麦品种根K+吸收动力学曲线均符合Michaelis-Menten方程, 即V=Vmax×[S]/([S]+Km)+k×[S]。低浓度(低于25mmol·L-1) NaCl处理对根高亲和K+吸收系统转运K+具有促进作用, 对耐盐品种‘德抗961’的促进作用更大。小麦根高亲和K+吸收系统是通过K+/H+同向转运, 而不是K+/Na+同向转运。NaCl处理对根低亲和K+吸收系统有抑制作用, 对盐敏感品种‘鲁麦15’的抑制作用更大。NaCl处理导致2个小麦品种根和叶片中的K+含量显著下降, Na+含量显著升高, 但‘德抗961’根和叶片中的K+含量均显著高于‘鲁麦15’, ‘德抗961’根中Na+含量显著高于‘鲁麦15’, 而其叶片中Na+含量显著低于‘鲁麦15’, 从而保证NaCl胁迫下其叶片较高的K+/Na+比。非选择性阳离子通道是小麦根Na+吸收的主要途径, K+通道是Na+吸收的一条重要途径。这些结果表明小麦部分通过调节根系K+吸收系统而维持叶片较高的K+/Na+比, 从而提高其耐盐性。

关键词：小麦; NaCl胁迫; 根Na+、K+吸收; 耐盐性

收稿：2012-10-15   修定：2012-11-16

资助：国家自然科学基金(30270793)和国家支撑计划项目(2009BADA7B05)。

Characteristics of Na⁺ and K⁺ Uptake in Roots of Different Salt-Tolerant Wheat Cultivars

DING Tong-Lou, JIA Yu-Hui, BAO Jing, WANG Bao-Shan*

Key Lab of Plant Stress Research, College of Life Sciences, Shandong Normal University, Jinan 250014, China

Corresponding author: WANG Bao-Shan; E-mail: bswang@sdnu.edu.cn; Tel: 0531-86180197

Abstract:

Salt-tolerant wheat cultivar ‘DK961’ and salt-sensitive wheat cultivar ‘LM15’ were used to investigate the characteristics of Na⁺ and K⁺ uptake and correlation with salt tolerance. Results showed that K+ uptake kinetics of roots was fitted to the Michaelis-Menten equation, namely V=V_max×[S]/([S]+K_m)+k×[S], for both cultivars. Low concentration NaCl (<25 mmol·L^-1) treatment significantly enhanced high-affinity K⁺ uptake system, and the effects on ‘DK961’ was stronger than that on ‘LM15’. High-affinity K⁺ uptake of wheat roots possibly is driven by K⁺/H⁺ symporter instead of K⁺/Na⁺ symporter. NaCl treatment inhibited low-affinity K⁺ uptake system, and the effects on ‘LM15’ was stronger than that on ‘DK961’. The K⁺ content in roots and leaves significantly decreased in response to NaCl stress, while the Na⁺ content significantly increased under NaCl stress. Under NaCl stress, K⁺ content in roots and leaves of ‘DK961’ was significantly higher than that of ‘LM15’, and the Na⁺ content of roots in ‘DK961’ was significantly higher than that in ‘LM15’. However, leaf Na⁺ content of ‘DK961’ was significantly lower than that of ‘LM15’ under NaCl stress. Therefore, K⁺/Na⁺ ratio in leaves of ‘DK961’ was higher than that in ‘LM15’ in response to NaCl stress. NSCCs (non-selective cation channels) are the main pathways for Na⁺ uptake, and K⁺ channels mediate Na⁺ uptake. These results suggested that wheat enhanced salt tolerance partly via regulating root K⁺ uptake system contributed to high K⁺/Na⁺ ratio of leaves.

Key words: wheat; NaCl stress; Na⁺, K⁺ uptake of root; salt tolerance