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作 者 ：张纪涛 韩坤 王林权 李翠

期 刊 ：植物营养与肥料学报 2012年 18卷 1期 页码：1-9

关键词：Na 胁迫；K 吸收动力学；K 高亲和吸收；K 低亲和吸收；温度型小麦；

Keywords:salt stress, K absorption kinetics, K high affinity transporter, K low affinity transporter, wheat cultivars with different canopy temperature,

摘 要 ：本试验采用吸收动力学方法结合药理学方法，研究了NR9405（暖型）、小偃六号（中间型）、RB6和陕229（冷型）等4种不同温度型小麦幼苗（14 d）K+ 的高亲和和低亲和吸收特征。结果表明： 1）在0～50mmol/L的K+浓度范围内，K+吸收可分为0～1和1～50mmol/L两个阶段，均可用米氏方程描述；2）对于高亲和吸收系统（0～1 mmol/L），冷型小麦具有高的饱和吸收率Imax [42.46～43.12 μmol/（h?g），RDW]和亲合系数Km（0.430～0.432 mmol/L），暖型小麦（NR9405）和小偃六号具有较低的Imax［33.57～35.38 μmol/（h?g），RDW］和Km（0.332～0.353 mmol/L），抑制低亲和系统后增加了4种小麦的高亲和转运载体数量，降低了冷型小麦对K+的亲和力，但对NR9405和小偃六号的Km值影响较小； 3）抑制高亲和吸收后，低亲和系统的Imax和Km均增加； 4）在盐胁迫下，K+高亲和和低亲和吸收系统均受到抑制，小麦幼苗K+吸收能力均显著降低，暖型小麦NR9405和小偃六号的高亲和系统Km几乎不受盐胁迫的影响，而冷型小麦的Km值因盐胁迫而降低。因此，在盐胁迫下高亲和吸收系统的稳定性可能是影响暖型小麦耐盐性高的一个重要因素，这对小麦耐盐性研究及耐盐品种选育均具有一定的指导意义。

Abstract:The absorption kinetics and pharmacology method were employed to study the effect of Na+ on regulation of K+ transporter systems characteristics using wheat genotypes with different canopy temperature. The wheat cultivars in this study included a warm climate cultivar (cv. ‘NR9405’), a moderate climate cultivar (cv. ‘Xiaoyan No. 6’), and two cold climate cultivars (cv. ‘RB6’ and cv. ‘Shaan229’). The results indicated that the dynamics of K+ uptake by wheat seedlings in the 0 to 50 mmol/L K+ treatment could be divided into two phases. The first phase consisted of higher affinity transport (HAT) of K+ whereas the second phase consisted of lower affinity transport (LAT). The K+ absorption velocity curves of both phases were best described by Michaelich-Menten equations. The Imax and Km of higher affinity transport were higher in both cold climate cultivars than in the moderate climate and the warm climate cultivars. This indicated that the K+ affinity capacities of Xiaoyan No. 6 and NR9405 were higher than those of RB6 and Shaan229. When the LATS was inhibited, the number of K+ carriers increased in all four wheat cultivars, but the affinity capacity in the cold climate cultivars declined, but did not in other two cultivars. The Imax values of the LAT system ranged from 183 to 253 μmol/(h?g), RDW and the Km values ranged from 20 to 30 mmol/L. When the HATS were inhibited, the Imax and Km of the LATS increased, indicating that number of carriers had increased but the affinity capacity of the carriers had decreased. Salt stress inhibited the absorption and transport capacity of K+ by the HAT and LAT systems in all four cultivars. The Km values of the HATS in NR9405 and Xiaoyan No. 6 were almost unaffected by Na+ stress. In contrast, Na+ stress reduced the Km values of the HATS system in the cold-climate genotypes. This indicates that the HATS of salt tolerant plants are stable. This finding has important implications for understanding the molecular mechanism of plant salt tolerance and nutrient uptake.

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