E. I. du Pont de Nemours & Company, Agricultural Products Department, Experimental Station, Wilmington, Delaware 19898.
Plant Physiol. 1988 Mar;86(3):811-6. doi: 10.1104/pp.86.3.811.
(a) excised bean leaf assay; (b) rooted bean leaf assay. Compounds assayed were N-alkylpyridiniums with systematic variation in octanol-water partition coefficients (log K(ow)), substituted benzoic acids with about the same log K(ow) value but variable acidities. Results of the assays strongly conform, quantitatively, to the predictions of the unified mathematical model. Results also indicate that the membrane permeability value of a compound, which depends directly on log K(ow) value, is the overriding factor in determining phloem mobility. When the weak acid functionality of a compound confers increased phloem mobility, it does so principally by making the log K(ow) value, and consequently the membrane permeability of the compound more optimal.
（a）离体豆叶测定法；（b）生根豆叶测定法。所测定的化合物为 N-烷基吡啶鎓，其具有系统的辛醇-水分配系数（log K（ow））变化，取代苯甲酸具有相近的 log K（ow）值但具有不同的酸度。测定结果在定量上非常符合统一数学模型的预测。结果还表明，化合物的膜透过性值直接取决于 log K（ow）值，是决定韧皮部移动性的主要因素。当化合物的弱酸官能团赋予增加的韧皮部移动性时，主要是通过使化合物的 log K（ow）值，以及因此更优化化合物的膜透过性来实现。
