Rains D W, Epstein E
Science. 1965 Jun 18;148(3677):1611. doi: 10.1126/science.148.3677.1611.
Two mechanisms are implicated in the absorption of alkali cations by barley roots. Mechanism 1 has a high affinity for potassium, but its affinity for sodium is so low that, in the presence of even a low concentration of potassium (1 mM), sodium absorption by this mechanism is all but abolished. Mechanism 2 has a much lower affinity for alkali cations and is not highly selective; it transports sodium as well as potassium.
大麦根系吸收碱金属阳离子涉及两种机制。机制1对钾具有高亲和力，但对钠的亲和力极低，以至于即使在低浓度钾（1 mM）存在的情况下，通过该机制的钠吸收几乎完全被消除。机制2对碱金属阳离子的亲和力要低得多，且选择性不强；它既运输钠也运输钾。
