K+高亲和转运系统吸收动力学特征及其受NH4+影响的研究
Kinetics of high affinity system for K+ and effects of NH4+
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摘要: 为探讨钾的高亲和转运系统是否受到铵离子的影响,采用溶液培养方法研究了水稻、大豆两种作物苗期(16d)的K+高亲和转运系统吸收动力学特征及其受吸收液中NH4+的影响。结果表明,NH4+对K+吸收的Vmax的影响在作物种类间有较大的差异,水稻受影响显著小于大豆。NH4+对供试作物K+吸收的Km值影响均很小,说明NH4+对K+吸收速率的影响主要在于影响了细胞膜上K+载体的数量而非影响了载体吸收位点与K+之间的亲和性。Abstract: The present work focused on the influence of NH4+ on the high affinity transport system(HATS) for K+.Hydroponic experiments were carried out to study the uptake kinetics of high affinity transport system for K+ by rice and soybean seedlings,and of their response to NH4+.The results indicated that the effect of NH4+ on Vmax of K+ uptake in rice was significantly lower than that in soybean.The influence of NH4+ on the values of Km of both two tested crops was neglected;indicating effects of NH4+ on K+ uptake are mainly attributed to its influence on the quantity of potassium carriers located at the cell membrane instead of on the affinity of the uptake sites for K+.
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