PHYSICOCHEMICAL FACTORS AFFECTING UPTAKE BY ROOTS AND TRANSLOCATION TO SHOOTS OF WEAK ACIDS IN BARLEY
PHYSICOCHEMICAL FACTORS AFFECTING UPTAKE BY ROOTS AND TRANSLOCATION TO SHOOTS OF WEAK ACIDS IN BARLEY
复制标题
DOI：
10.1002/ps.2780190203
复制
发表时间：
1987-01-01
期刊：
影响因子：
--
通讯作者：
BROMILOW, RH
中科院分区：
文献类型：
--
作者：
BRIGGS, GG;RIGITANO, RLO;BROMILOW, RH
从马来酰肼，flamprop和一系列的苯氧乙酸根的溶液中的吸收，以及随后的易位到芽，在大麦中进行了测量。随着溶液pH值的降低，吸收和转运都增加，变化的幅度在测试的化学品中各不相同。根的吸收可以通过离子阱机制来解释，该机制假设化学物质的进入主要是通过酸的未解离形式的被动扩散发生的，阴离子穿过细胞膜的速度非常缓慢。细胞膜的渗透性与未解离和解离形式的酸的比率由根中的积累来估计，在苯氧乙酸系列中，该比率最大（4 × 10 - 4）。105)用于中等亲脂性的化合物。马来酰肼和flamprop的比例低得多，为1.8 × 104。分别为102和103; flamprop的值远小于类似亲脂性的苯氧基乙酸，如2，4-二氯苯氧基乙酸，表明亲脂性可能不是决定植物中弱酸行为的唯一因素。向地上部的转运与根部的化学浓度大致成正比。
The uptake from solution of maleic hydrazide, flamprop and a series of phenoxyacetic acids by roots, and their subsequent translocation to shoots, was measured in barley. Both uptake and translocation increased as the pH of the solution decreased, the magnitude of the change varying amongst the chemicals tested. Uptake by roots could be accounted for by the ion-trap mechanism, which assumes that entry of the chemicals occurs largely by passive diffusion of the undissociated form of the acids, with passage of the anions across the cell membranes being very slow. The ratio of the permeability of the cell membranes to the undissociated and dissociated forms of the acids was estimated from the accumulation in roots, and in the phenoxyacetic acid series this ratio was maximal (4 .times. 105) for compounds of intermediate lipophilicity. Maleic hydrazide and flamprop had much lower ratios, 1.8 .times. 102 and 103 respectively; the value for flamprop was much less than for phenoxyacetic acids of similar lipophilicity, such as 2,4-dichlorophenoxyacetic acid, indicating that lipophilicity may not be the sole factor determining the behaviour of weak acids in plants. Translocation to shoots was approximately proportional to the chemical concentrations in the roots.