Department of Biology, Building 44, The University, SO9 5NH, Southampton, UK.
Planta. 1980 Jan;149(4):327-31. doi: 10.1007/BF00571165.
The putative auxin-transporting cells of the intact herbaceous dicotyledon are the young, differentiating vascular elements. The length of these cells was found to be considerably greater in dwarf (Meteor) than in tall (Alderman) varieties ofPisum sativum L., and to be greater in etiolated than in light-grown plants ofP. sativum cv Meteor andPhaseolus vulgaris L. cv Mexican Black. Under given light conditions during transport these large differences in cell length did not influence the shapes of the transport profiles or the velocity of transport of(14)C-labelled indol-3yl-acetic acid (IAA) applied to the apical bud. However, in both etiolated and light-grown bean and dwarf pea plants the velocity of transport in darkness was ca. 25% lower than that in light. Under the same conditions of transport velocities in bean were about twice those observed in the dwarf pea. Exposure to light during transport increased the rate of export of(14)C from the labelled shoot apex in green dwarf pea plants but not in etiolated plants. The light conditions to which the plants were exposed during growth and transport had little effect on the rates of uptake of IAA from the applied solutions. The results indicate that the velocity of auxin transport is independent of the frequency of cell-to-cell interfaces along the transport pathway and it is suggested that in intact plants auxin transport is entirely symplastic.
完整的草本双子叶植物的假定生长素运输细胞是年轻的、分化的维管束元素。这些细胞的长度在矮化（流星）品种的豌豆中比在高大（奥尔德曼）品种中长得多，在光下生长的豌豆流星和菜豆品种墨西哥黑的植株中比在黄化植株中长得多。在运输过程中，在给定的光照条件下，这些细胞长度的巨大差异不会影响运输轮廓的形状或(14)C 标记的吲哚-3-乙酸（IAA）施加到顶端芽时的运输速度。然而，在黄化和光下生长的豆和矮化豌豆植物中，黑暗中的运输速度比光下低约 25%。在相同的运输条件下，豆的运输速度约为矮化豌豆的两倍。在运输过程中暴露在光下会增加绿色矮化豌豆植物中从标记的顶端芽中(14)C 的出口率，但不会增加黄化植物的出口率。植物在生长和运输过程中暴露的光照条件对从应用溶液中吸收 IAA 的速度几乎没有影响。结果表明，生长素运输的速度与运输途径中细胞-细胞界面的频率无关，并且表明在完整的植物中，生长素运输是完全共质体的。
