Potassium transporters play crucial roles in K^＋ uptake and translocation in plants. However, so far little is known about the regulatory mechanism of potassium transporters. Here, we show that a Shaker-like potassiu...Potassium transporters play crucial roles in K^＋ uptake and translocation in plants. However, so far little is known about the regulatory mechanism of potassium transporters. Here, we show that a Shaker-like potassium channel AtKC1, encoded by the AtLKT1 gene cloned from the Arabidopsis thaliana low-K^＋ （LK）-tolerant mutant Atlktl, significantly regulates AKTl-mediated K^＋ uptake under LK conditions. Under LK conditions, the Atkcl mutants maintained their root growth, whereas wild-type plants stopped their root growth. Lesion of AtKC1 significantly enhanced the tolerance of the Atkcl mutants to LK stress and markedly increased K^＋ uptake and K^＋ accumulation in the Atkclmutant roots under LK conditions. Electrophysiological results showed that AtKC1 inhibited the AKT1-mediated inward K^＋ currents and negatively shifted the voltage dependence of AKT1 channels. These results demonstrate that the ‘silent＇ K^＋ channel α-subunit AtKC1 negatively regulates the AKTl-mediated K^＋ uptake in Arabidopsis roots and consequently alters the ratio of root-to-shoot under LK stress conditions.展开更多
土壤系统经常表现出复杂的性质并导致溶质迁移的异常扩散。基于Skaggs等人的模型,本文研究开发蒸腾和根系吸水条件下的时间分数阶对流扩散方程(FADE)模型,以模拟根区的异常扩散并进行解析求解。模拟表明,时间分数阶对流扩散模型与整数...土壤系统经常表现出复杂的性质并导致溶质迁移的异常扩散。基于Skaggs等人的模型,本文研究开发蒸腾和根系吸水条件下的时间分数阶对流扩散方程(FADE)模型,以模拟根区的异常扩散并进行解析求解。模拟表明,时间分数阶对流扩散模型与整数阶对流扩散模型的数值结果在表面土壤附近出现偏差,随后随着时间的推移逐渐向下移动,偏差随深度逐渐扩大,较小的α对应较高的浓度曲线,说明土壤中溶质储层较强,导致溶质运移速度较慢,即存在亚扩散。Soil systems often exhibit complex properties and lead to abnormal diffusion of solute transport. Based on the model of Skaggs et al., this paper develops a time fractional advection-diffusion equation (FADE) model under transpiration and root water absorption conditions to simulate abnormal diffusion in the root zone and solves it analytically. The simulation shows that the numerical results of the time fractional advection-diffusion model and the integer advection-diffusion model deviate near the surface soil, and then gradually move downward with time. The deviation gradually expands with depth, and the smaller one corresponds to a higher concentration curve, indicating that the solute reservoir in the soil is strong, resulting in a slower solute migration rate, that is, there is sub-diffusion.展开更多
基金Acknowledgments We thank Dr Emily Liman （University of Southern California, USA） for providing the pGEMHE vector for the Xenopus oocyte experiments. We also thank Dr Richer Gaber （Northwestern Uni- versity, USA） for providing the yeast mutant strain with K＋ transport deficiency. We are grateful to Dr Rainer Hedrich （University of Wurzburg, Germany） for critical discussion. This work was supported by the National Natural Science Foundation of China （grant no. 30830013 to WHW）, the Beijing Municipal Education Commission （grant no. YB20081001901 to WHW） and the Program of Introducing Talents of Discipline to Universities （grant no. B06003 to WHW）.
文摘Potassium transporters play crucial roles in K^＋ uptake and translocation in plants. However, so far little is known about the regulatory mechanism of potassium transporters. Here, we show that a Shaker-like potassium channel AtKC1, encoded by the AtLKT1 gene cloned from the Arabidopsis thaliana low-K^＋ （LK）-tolerant mutant Atlktl, significantly regulates AKTl-mediated K^＋ uptake under LK conditions. Under LK conditions, the Atkcl mutants maintained their root growth, whereas wild-type plants stopped their root growth. Lesion of AtKC1 significantly enhanced the tolerance of the Atkcl mutants to LK stress and markedly increased K^＋ uptake and K^＋ accumulation in the Atkclmutant roots under LK conditions. Electrophysiological results showed that AtKC1 inhibited the AKT1-mediated inward K^＋ currents and negatively shifted the voltage dependence of AKT1 channels. These results demonstrate that the ‘silent＇ K^＋ channel α-subunit AtKC1 negatively regulates the AKTl-mediated K^＋ uptake in Arabidopsis roots and consequently alters the ratio of root-to-shoot under LK stress conditions.
文摘土壤系统经常表现出复杂的性质并导致溶质迁移的异常扩散。基于Skaggs等人的模型,本文研究开发蒸腾和根系吸水条件下的时间分数阶对流扩散方程(FADE)模型,以模拟根区的异常扩散并进行解析求解。模拟表明,时间分数阶对流扩散模型与整数阶对流扩散模型的数值结果在表面土壤附近出现偏差,随后随着时间的推移逐渐向下移动,偏差随深度逐渐扩大,较小的α对应较高的浓度曲线,说明土壤中溶质储层较强,导致溶质运移速度较慢,即存在亚扩散。Soil systems often exhibit complex properties and lead to abnormal diffusion of solute transport. Based on the model of Skaggs et al., this paper develops a time fractional advection-diffusion equation (FADE) model under transpiration and root water absorption conditions to simulate abnormal diffusion in the root zone and solves it analytically. The simulation shows that the numerical results of the time fractional advection-diffusion model and the integer advection-diffusion model deviate near the surface soil, and then gradually move downward with time. The deviation gradually expands with depth, and the smaller one corresponds to a higher concentration curve, indicating that the solute reservoir in the soil is strong, resulting in a slower solute migration rate, that is, there is sub-diffusion.
