【摘要】 【目的】本研究旨在揭示棉花钾离子（K⁺）吸收机制。【方法】以国欣棉3号和中棉所41为材料,应用病毒诱导基因沉默技术研究棉花K⁺通道基因GhAKT1和K⁺转运体基因GhKT2的功能。【结果】在低水平供K⁺(0.1 mmol·L^-1)和充分供K⁺(2.5 mmol·L^-1)条件下,沉默GhAKT1和GhKT2基因使棉花幼苗的K⁺积累量分别降低15%左右和25%以上。此外,沉默GhAKT1和GhKT2基因导致棉花幼苗对K⁺的最大吸收速率和亲和能力出现不同程度的下降。药理学试验结果表明,在外界K⁺浓度低于250μmol·L^-1的条件下,高亲和系统对棉花K⁺吸收的贡献大于K⁺通道;而且GhAKT1蛋白可能是1个对NH4+比较敏感的组分。【结论】棉花K⁺通道蛋白GhAKT1和K⁺转运体蛋白GhKT2具有吸收K⁺的功能,而且表现出双亲和吸收K⁺的特性,可作为改善棉花钾营养的候选基因。更多还原

【Abstract】 [Objective] The objective of this study was to reveal the mechanism underlying potassium（K⁺） uptake in cotton.[Method] We used virus-induced gene silencing to examine the functions of the K⁺channel（GhAKT1） and K⁺transporter（GhKT2） genes in two cotton cultivars, namely Guoxin 3 and CCRI 41. [Results] The silencing of these two genes decreased K⁺levels by about 15% and more than 25% at low(0.1 mmol·L^-1) and sufficient(2.5 mmol·L^-1) K⁺concentrations, respectively. Regarding the parameters affecting K⁺uptake kinetics, the silencing of GhAKT1 and GhKT2 decreased Imax（per root dry weight）,but increased Kmto varying levels. Additionally, the results of pharmacological tests indicated that the contribution of a high-affinity K⁺uptake system to the absorption of K⁺is greater than that of K⁺channels in cotton at external K⁺concentrations below 250 μmol·L^-1. Furthermore, GhAKT1 activity may be sensitive to NH4+. [Conclusion] These results suggest that GhAKT1 and GhKT2 are associated with low- and high-affinity K⁺uptake in cotton. These genes may be useful for increasing cotton K⁺contents.更多还原